Pharmacology | definition of pharmacology by Medical dictionary Pharmacology | definition of pharmacology by Medical dictionary Related to pharmacology: pharmacokinetics , Clinical pharmacology pharmacology [fahr″mah-kol´o-je] the science that deals with the origin, nature, chemistry, effects, and uses of drugs; it includes pharmacognosy, pharmacokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. adj., adj pharmacolog´ic. phar·ma·col·o·gy (far'mă-kol'ŏ-jē), The science concerned with drugs, their sources, appearance, chemistry, actions, and uses. [pharmaco- + G. logos, study] pharmacology /phar·ma·col·o·gy/ (-kol´ah-je) the science that deals with the origin, nature, chemistry, effects, and uses of drugs; it includes pharmacognosy, pharmocokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. pharmacology 1. The science of drugs, including their composition, uses, and effects. 2. The characteristics or properties of a drug, especially those that make it medically effective.

phar′ma·co·log′ic (-kə-lŏj′ĭk), phar′ma·co·log′i·cal (-ĭ-kəl) adj. phar′ma·co·log′i·cal·ly adv. phar′ma·col′o·gist n. pharmacology (phar) Etymology: Gk, pharmakon + logos, science the study of the preparation, properties, uses, and actions of drugs. pharmacology The field that studies the characteristics, effects and uses of drugs and their interactions with living organisms. pharmacology The study of the science and clinical application of medications; the study of drugs, their sources, their nature and properties. See Clinical pharmacology, Cosmetic pharmacology, Recombinant pharmacology . phar·ma·col·o·gy (fahr'mă-kol'ŏ-jē) The science concerned with drugs and their sources, appearance, chemistry, actions, and uses. [pharmaco- + G. logos, study] pharmacology The science of DRUGS .

Pharmacology is concerned with the origins, isolation, purification, chemical structure and synthesis, assay, effects, uses, side effects, relative effectiveness of drugs and the influence of genetic factors on drug action. It thus includes, among other disciplines, GENETICS , ORGANIC CHEMISTRY , PHARMACOKINETICS , THERAPEUTICS and TOXICOLOGY . pharmacology the study of pharmaceutical agents, their preparation, uses and effects. phar·ma·col·o·gy (fahr'mă-kol'ŏ-jē) Pharmaceutical medications | definition of Pharmaceutical medications by Medical dictionary Pharmaceutical medications | definition of Pharmaceutical medications by Medical dictionary Related to Pharmaceutical medications: Prescription medication pharmacology [fahr″mah-kol´o-je] the science that deals with the origin, nature, chemistry, effects, and uses of drugs; it includes pharmacognosy, pharmacokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. adj., adj pharmacolog´ic. phar·ma·col·o·gy (far'mă-kol'ŏ-jē), The science concerned with drugs, their sources, appearance, chemistry, actions, and uses. [pharmaco- + G.

logos, study] pharmacology /phar·ma·col·o·gy/ (-kol´ah-je) the science that deals with the origin, nature, chemistry, effects, and uses of drugs; it includes pharmacognosy, pharmocokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. pharmacology 1. The science of drugs, including their composition, uses, and effects. 2. The characteristics or properties of a drug, especially those that make it medically effective. phar′ma·co·log′ic (-kə-lŏj′ĭk), phar′ma·co·log′i·cal (-ĭ-kəl) adj. phar′ma·co·log′i·cal·ly adv. phar′ma·col′o·gist n. pharmacology (phar) Etymology: Gk, pharmakon + logos, science the study of the preparation, properties, uses, and actions of drugs. pharmacology The field that studies the characteristics, effects and uses of drugs and their interactions with living organisms.

pharmacology The study of the science and clinical application of medications; the study of drugs, their sources, their nature and properties. See Clinical pharmacology, Cosmetic pharmacology, Recombinant pharmacology . phar·ma·col·o·gy (fahr'mă-kol'ŏ-jē) The science concerned with drugs and their sources, appearance, chemistry, actions, and uses. [pharmaco- + G. logos, study] pharmacology The science of DRUGS . Pharmacology is concerned with the origins, isolation, purification, chemical structure and synthesis, assay, effects, uses, side effects, relative effectiveness of drugs and the influence of genetic factors on drug action. It thus includes, among other disciplines, GENETICS , ORGANIC CHEMISTRY , PHARMACOKINETICS , THERAPEUTICS and TOXICOLOGY . pharmacology the study of pharmaceutical agents, their preparation, uses and effects. phar·ma·col·o·gy (fahr'mă-kol'ŏ-jē) Science concerned with drugs, their sources, appearance, chemistry, actions, and uses. [pharmaco- + G.

logos, study] n the total science of drugs, including their use in therapeutics. pharmacology the science that deals with the origin, nature, chemistry, effects and uses of drugs; it includes pharmacognosy, pharmacokinetics, pharmacodynamics, pharmacotherapeutics and toxicology. Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: Biologics Evaluation Section References in periodicals archive ? As part of this 2006 study of fatal pharmaceutical intoxications, 295 deaths were identified as the result of clearly accidental fatal drug abuse, rather than suicidal drug over-use or drug use circumstances unclear for intentionality, where one or more pharmaceutical medications were significantly contributory to death. Epidemic: fatal pharmaceutical abuse in West Virginia 1991-2008 While the arthritis drug Vioxx, pulled from the market by its manufacturer after it was shown to double the risk of heart attack and stroke, remains the most high-profile example, a significant number of pharmaceutical medications have been linked with health risks in recent years.

New generation of biomarkers may help reduce the health risks of pharmaceutical drugs It is in the best interests of Georgians to exempt from sales and use taxes pharmaceutical medications that are distributed without cost for several reasons, including: (1) the ability to distribute needed medicines to persons that might not otherwise be able to afford them; (2) the attraction of clinical trials to Georgia for the betterment of the health of Georgians and to continue the State's place as a leader in cutting-edge health research; and (3) the elimination of an inconsistency in the law whereby pharmaceutical medicines that are sold at retail are not taxed, however those that are distributed for free are subject to taxation. Pharmacology Anesthesia Pharmacology The science that deals with origin, nature, chemistry, effects, and uses of drugs includes pharmacokinetics, pharmacodynamics, - ppt download Download Presentation is loading. Please wait.

Pharmacology Anesthesia Pharmacology The science that deals with origin, nature, chemistry, effects, and uses of drugs includes pharmacokinetics, pharmacodynamics, Published by Suzan Hudson Modified about 1 year ago Embed Similar presentations More Presentation on theme: "Pharmacology Anesthesia Pharmacology The science that deals with origin, nature, chemistry, effects, and uses of drugs includes pharmacokinetics, pharmacodynamics,"— Presentation transcript: 1 2 Pharmacology Anesthesia 3 Pharmacology The science that deals with origin, nature, chemistry, effects, and uses of drugs includes pharmacokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology drugs are good, but may be only one factor 4 Modes of Drug Action Stimulation: increases the activity of cells (doxapram) Depression: decrease cellular activity (atropine) Irritation: leads to stimulation of activity (fleet enemas) Replacement: synthetic substitutes (insulin or synthroid) Chemotherapy: kill malignant tumor cells (Taxol or Doxorubicin) 5 Drug Classification Classification systems: primary effect & site of action Primary effect: unknown cause, but drug may relieve clinical signs Site of action: organ specific drugs 6 Routes of Administration Enteral: drugs are delivered directly

 into GI tract; slower absorption; wider safety margin –Oral & Rectal –Oral: tablets, capsules, powders, solutions, caplets, suspensions –powders, solutions, or suspensions: mix with food or require administration via stomach tube –Rectal: suppositories or enemas 7 Routes of Administration Parenteral: without or around (par) the intestines (enteral) –IV, SC, ID, IM, IP, IC –quickest route to get drug into animal & to site of action –other routes: Intra-articular; Subarachnoid or Intrathecal, subconjunctival –drugs given should be sterile, nonirritating, and pyrogen-free 8 Routes of Administration Inhalation: directly into respiratory tract –gas, vapor, fine mist or powder –particles or droplets must be less than 5um –most commonly used for anesthetic gases (i.e.

isoflurane) –advantages: rapid absorption and elimination –disadvantages: intubation, mask, or inhalation chamber 9 Routes of Administration Topical: application to skin or external membranes –lotions, ointments, pastes, and suspensions –slowest rate of absorption –advantages: high doses to local area without systemic toxicity –disadvantages: fur, dirt, bedding, licking 10 Dosage Forms Enteral forms: solutions, suspensions, capsules, or tablets Solutions: water based, tinctures, spirits, fluid extractions Suspensions: insoluble drugs Capsules: soluble in stomach or intestine (time-release) Tablets: solid preparations (enteric coating) 11 Dosage Forms Parenteral forms: mixed or dissolved in a sterile, pyrogen-free medium IV, IA, IC drugs: dissolved in water, isotonic saline, or saline-dextrose Depot effect: drug dissolve slowly gives a constant drug level 12 Therapeutic Use of Drugs Tolerance: decrease in response to normal dose (e.g., NHP to ketamine) Sensitization: increase in response (e.g., allergic reactions) Synergistic: two or more drug which give an enhanced response (e.g

., antibiotics) Potentiation: increased action by one drug produced by another drug with nonrelated action 13 Therapeutic Use of Drugs All drugs have a toxic effect if given in excess Therapeutic Index or Margin of Safety TI = Toxic dose/Effective dose 14 Distribution and Elimination Distribution of drugs within the body varies considerably Most drugs are inactivated by normal metabolic processes Kidneys: primary route of excretion Other routes: bile, respiratory Metabolism: mostly occurs in the liver 15 Controlled Drugs Schedule III-V: less potential for abuse (ketamine, butorphanol) Requires federal and state licenses Detailed records showing usage Facilities which use controlled drugs may be inspected by DEA Must be stored behind at least two locked doors 16 Controlled Drugs Potential for being abused or addictive Comprehensive Drug Abuse and Control Act: lists control drugs and 5 schedules Schedule I: high potential for abuse; no medical treatment, no safety (LSD, heroin) Schedule II: high potential for abuse, but have medical uses (codeine, opium derivatives, pentobarbital) 17 Dogs Parvovirus: –acute disease of young dogs –bloody diarrhea and severe panleukopenia Otitis Externa: –bacteria,

 yeast, ear mites (Otodectes cynotis) –factors: dirt, trauma, hair, foreign bodies –excess head shaking and odor Heartworms: –Dirofilaria immitis; spread by mosquitos –adults live in pulmonary artery, right artium, and right ventricle 18 ANESTHESIA Review dosage calculations using ratios and cross multiplication Review the stages and planes of anesthesia Stage 1 - narcosis, sedation, analgesia Stage 2 - uninhibited response, delirium, excitement Stage 3 - surgical stage Plane 1 - loss of pain response Plane 2 - surgical plane Plane 3 - beginning of respiratory paralysis/pupil dilation Plane 4 - cyanosis, non-responsive pupils Stage 4 - paralysis of brain respiratory centers 19 ANESTHESIA Monitoring General Anesthesia Respiratory Pattern - rate, depth and character of the respirations Shallow, thoracic pattern = lightly anesthetized Deep, abdominal pattern = deeply anesthetized Pattern should be regular Monitored by observing flow valves, rebreathing bag, observing chest movement, in-line flow meter 20 ANESTHESIA Monitoring General Anesthesia Mucous membrane color

 - The gums, lips, rectum/vulva remain pink if the animal is receiving enough oxygen.

They turn blue if there is a lack of oxygen. Capillary refill time - Measured by pressing on the gum line until the color blanches and timing its return to normal color when pressure is released. Normal is 2 seconds or less. Longer times indicate a perfusion problem from lowered cardiac output, increased vascular resistance, or hypovolemia. 21 ANESTHESIA Monitoring General Anesthesia Pulse evaluation - Done on the femoral or mandibular artery or the heart itself. The strength and character of the pulse vary with anesthetic depth and blood pressure. Blood pressure - Blood pressure can be measured indirectly using a pressure cuff on the tail or leg and an ultrasonic doppler flow detector. An arterial catheter can be used for direct BP. 22 ANESTHESIA Monitoring General Anesthesia Body temperature - Anesthesia affects the brain’s heat regulatory center, lowering the patient’s temperature. Loss is minimized by using a heating pad, warm fluids, and a heat lamp during recovery. Cooler temperatures slow the metabolism of the anesthetic.

Eyes - Presence or absence of reflexes or nystagmus, and size of the pupil indicate the level of anesthesia 23 ANESTHESIA Monitoring General Anesthesia Muscle tone - varies with type of anesthesia used. Ketamine results in stiff, rigid muscles. Most other anesthetics result in some degree of relaxation which is easily observed in the larger species using jaw tone. Reflexes - most common is the pedal or withdrawal reflex, anal reflex also used. Both disappear as surgical plane reached. Laryngeal reflex used to determine time to remove endotracheal tube 24 Preanesthetics ANESTHESIA Preanesthetics Preanesthetics include tranquilizers, analgesics, and anticholinergicsPreanesthetics include tranquilizers, analgesics, and anticholinergics Tranquilizers - lower the animals apprehension and aid in restraint for anesthetic inductionTranquilizers - lower the animals apprehension and aid in restraint for anesthetic induction Analgesics - work with the tranquilizer to lower the amount of general anesthetic needed, increasing the safety margin.

CAN MASK THE ANESTHETIC STAGES.Analgesics - work with the tranquilizer to lower the amount of general anesthetic needed, increasing the safety margin. CAN MASK THE ANESTHETIC STAGES. Anticholinergics - reduce secretions and raise heart rateAnticholinergics - reduce secretions and raise heart rate 25 Preanesthetics ANESTHESIA Preanesthetics Anticholinergics - Atropine blocks acetylcholine resulting in decreased secretions from salivary and respiratory glands; blocks the vagal tone on the heart, increasing the heart rate Tranquilizers - Phenothiazines reduce anxiety and cause muscular relaxation. Note: These agents cause peripheral vasodilation and hypotension. -Analgesics - Medetomidine, Xylazine provides some anesthesia as well as analgesia and sedation. Often used with ketamine. 26 ANESTHESIA Injectable Anesthetics Pentobarbital - Not to be confused with Phenobarbital. Long acting anesthetic that can be given IV or IP. For IV administration, half the dose is given quickly then titrated to the desired effect. No reversal agent.

Must be very deep for analgesia. Thiamylal, thiopental, methohexital - Ultrashort acting (about 15 minutes) agents commonly used for general gas anesthetic induction. 27 ANESTHESIA Injectable Anesthetics Chloral hydrate - Used primarily as a sedative/hypnotic due to poor analgesic properties. Can cause profound depression of cardiovascular and respiratory systems. Alpha-Chloralose - Poor analgesia and slow onset. Used in physiological studies since there is little effect on the cardiovascular and respiratory systems. Primarily used as a sedative. 28 ANESTHESIA Injectable Anesthetics Urethane (Ethyl Carbamate) - Long lasting anesthetic. Has been associated with increased tumor formation. Can cause intestinal irritation if given IP. Usually used for long, terminal experiments. Tricaine Methanesulfonate (MS-222) - A water soluble anesthetic frequently used for fishes and amphibians. Fentanyl/Droperidol (Innovar-Vet) - An opioid and tranquilizer. Used for minor painful procedures. 29 ANESTHESIA Injectable Anesthetics Ketamine HCl - A dissociative anesthetic.

Administration results in excessive muscular tone, very mild respiratory depression, mild cardiac stimulation, salivation, adequate somatic but poor visceral analgesia. May produce seizures in some animals. Often used with xylazine for muscle relaxation and additional analgesia. 30 ANESTHESIA Inhalant Anesthetics Delivery and elimination occurs via the lungs = easy to adjust level of anesthesia being administered. Supplied as a liquid that slowly evaporates at room temperature. Carrier gases (oxygen +/- nitrous oxide) enter vaporizer where anesthetic gas vapor is added. Unused anesthetic gas and exhaled CO 2 must be removed. 31 ANESTHESIA Inhalant Anesthetics - Delivery Systems Chamber system - Clear plastic or glass container with cotton soaked in anesthetic placed in bottom and covered by mesh or perforated floor. Animal placed on floor and lid put on container. Anesthetic induction can be observed through the container wall. Once animal is removed, recovery begins. Open Drop system - Nose cone with anesthetic soaked cotton used to maintain animals induced above. Both systems must be used in a fume hood.

32 ANESTHESIA Inhalant Anesthetics - Delivery Systems Rebreathing systems allows recirculation of carrier and anesthetic gas and consist of a number of components 33 ANESTHESIA Inhalant Anesthetics - Delivery Systems Vaporizer –- Precision vaporizers are the most accurate and most commonly used type today. It automatically compensates for changes in vapor pressure due to temperature. –Copper kettle - older style that requires user to adjust for temperature variations –Wick-type - Used only with methoxyflurane since delivery concentration determined by liquid’s vapor pressure 34 ANESTHESIA Inhalant Anesthetics - Delivery Systems Lime Canister - Soda lime (calcium hydroxide or barium hydroxide) used to absorb the carbon dioxide in the expired air. A chemical indicator changes color when the soda lime should be replaced. Compressed Oxygen - Supplied in tanks available in a variety of sizes, green color code, full tanks ~2200 psi indicated on regulator pressure gauge, delivery controlled by flowmeter (measured in l/m). 35 ANESTHESIA Inhalant Anesthetics - Delivery Systems Tubing and rebreathing bag - Allow for the one-way system to function.

Rebreathing bag expands/contracts with each breath, should have a capacity of about 6 times the patient’s tidal volume. Pressure relief (Pop-off) valve - Adjustable, used to fine-tune flow rate so that the rebreathing bag stays about 2/3 full. 36 ANESTHESIA Inhalant Anesthetics - Delivery Systems Scavenger systems - Used to remove the excess exhaled gases = Waste Anesthetic Gas or WAG –Most effective is direct exhaust to the outside via central vacuum –Activated charcoal canisters used on portable setups Leakage of anesthetic around tubing connections, around endotracheal tube, and at machine connections can occur and frequent equipment inspections should be performed. 37 ANESTHESIA Inhalant Anesthetics - Delivery Systems Non-rebreathing systems - used for animals weighing ~ 7kg or less. Their tidal volume is too small to use the rebreathing systems so they use equipment that provides linear flow through the animal and then out to the scavenging device. This set-up produces large amounts of WAG. 38 ANESTHESIA Inhalant Anesthetics Vapor pressure - the higher the vapor pressure of a liquid, the quicker it will evaporate at a given temperature.

The reason halothane and isoflurane can’t be used in the open drop system but methoxyflurane can is due to the differences in vapor pressure. Tissue solubility - the greater the solubility of the gas in tissue, the slower the induction and the longer the recovery. Less soluble anesthetics are more potent. 39 ANESTHESIA Inhalant Anesthetics Diethyl Ether - highly flammable and explosive and must be used in explosion proof hoods. High tissue solubility = slow induction and recovery Chloroform - NOT TO BE USED IN ANIMAL FACILITIES. Can be highly toxic to mice, has low margin of safety, is a known carcinogen. 40 ANESTHESIA Inhalant Anesthetics Methoxyflurane - Low vapor pressure and high tissue solubility = safe. Can use wick- type vaporizers. Provides some analgesia after anesthetic recovery Halothane - Common veterinary inhalant anesthetic. High vapor pressure and low tissue solubility - use only precision vaporizers. Has been associated with cardiac arrhythmias. Isoflurane - Similar to halothane but no cardiac problems.

41 ANESTHESIA Inhalant Anesthetics Nitrous Oxide - Like oxygen, nitrous exists in a gaseous state at room temperature and is supplied in (blue) tanks. Under pressure it becomes a liquid. Tank pressure remains even (~800 psi) until there is no more liquid, then it decreases as the remaining gas is used. Nitrous is combined with oxygen and should make up 50-80% of the carrier gas combination to be effective. Low tissue solubility = rapid onset and recovery. Discontinue nitrous several minutes before oxygen 42 ANESTHESIA Neuromuscular Blockers ALWAYS USED IN CONJUCTION WITH GENERAL ANESTHESIA AND APPROPRIATE MONITORING gallamine, pancuronium, succinylcholine These agents cause paralysis of the voluntary skeletal muscles and, at higher doses, the diaphragm. Usually used with a ventilator. They provide NO analgesia.

Indications: fractures, dislocations, laparotomies Use BP, HR, mucous membrane color and capillary refill time to monitor anesthetic depth 43 Analgesics NSAIDs - act by inhibiting prostaglandin synthesis, good for inflammation but not good for pain. Oral delivery. - Aspirin and Acetaminophen have limited use. - flunixin, ketoprofen, and carprofen Opioids –Morphine provides sedation and analgesia. May also cause vomiting and defecation, cardiac and respiratory depression. Can see tremors/convulsions in mice and cats.

–Meperidine, Oxymorphone, Pentazocine, Buprenorphine 44 Postanesthesia and Emergency Care Drugs to keep on hand for emergencies: –Apomorphine - induces vomiting –Atropine sulfate - increases heart rate –Calcium gluconate - strengthens myocardium contractions –Chlorpromazine - tranquilizer –Dexamethasone - steroid for shock/anaphylaxis –Doxapram - stimulates breathing –Epinephrine HCl - for asystole –Heparin - dissolves blood clots –Lactated Ringer’s - increases blood volume –Morphine HCl - analgesia –Pentobarbital - anesthesia –Pitocin - stimulates uterus –Sodium bicarbonate - acidosis –Normal saline - increases blood volume –Isoproterenol - stimulates heart 45 Postanesthesia and Emergency Care Evaluation of patients should include behavioral observations and a complete physical examination Emergencies can usually be prevented by careful attention to the patient before, during, and after the anesthetic administration Technicians should work with the veterinarians both to avoid problems from occurring and to learn from those that do occur to prevent them from happening again.

What is Human Pharmacology? | Hospitals | Medical Specialists | Reviews What is Human Pharmacology? What does it mean? Pharmacology is a science subject that deals with the origin, nature, chemistry, uses, and effects of drugs and medication. However, in order to understand pharmacology better, it would be useful to know the basics of biochemistry and physiology. Pharmacology is a broad topic covering all areas including 'what the body does to every drug' and 'what every drug does to the body'. Stop! Did you digest that, or were you pondering what that is all about! Well, let's take you further… Why is it important to learn about pharmacology? Drugs are powerful tools for all medical doctors. Without drugs, you will probably be screaming even during a minor surgery, what more if it is a major one! Imagine, if there is a world without drugs, you'd probably be listening to a wailing world! Knowing 'what drug to use', 'when to use' and 'how much to use' is naturally very important to a medical doctor. The reputation of 'drugs' has been tainted due to the abuse of drugs.

In order to disassociate from that reputation, the word 'medicine' is sometimes used instead. Many times, victims of drug abuse are ignorant of what they are taking. Drug addicts tend to begin with a single dose and derive pleasure from that. Not knowing the side effects and mid to long term effects of the drug, the poor souls inadvertently continue to use it and eventually the usage becomes excessive. In time, they get addicted to the drug; not knowing that it has what they called a 'withdrawal effect'. That means when you have started taking the drug and you stop taking it, you will feel restless and painful all over. On the other hand, you need not be worried about the drugs given to you by your doctor (provided he/she is a qualified one, of course!). Nevertheless, if case you desire to, you can always query your doctor on what type of drugs that are prescribed to you. Not all drugs have withdrawal effects. There are probably thousands of drugs that available today. New ones are coming out every now and then. It is impossible to remember each one of them. It is also impossible for the doctors to remember every drug that exist in this world.

To make it easier to remember or to keep a record of these drugs, we tend to categorize these drugs. Say, whether they fall under the category of antibiotics or painkillers for example. Then under each category, there are similarities and dissimilarities between each drug. Your doctor will prescribe the ones that are most suitable for you and naturally, the ones that he is most confident with. Due to the genetic differences that exist within each of us, some drugs may work on you but may not work on others. Some drugs may benefit you but may cause harm to another e.g. allergic reaction. Usually before prescribing any form of medication, a doctor, if he is unfamiliar with your medical history, will query you for any history of allergies etc. Do let him know beforehand, because it can affect the type of drugs that are prescribed to you! Therefore, precision and individualization are very much required in order to ensure that the right drugs or perhaps I should say 'medicine', is given to the right person, at the right time, at the right dose and at the right place.

More interesting reads on pharmacology: (Basic to mid-level: suitable for public and medical students): Chapter 3: Drugs From Nature, Then and Now - Medicines By Design - Science Education - National Institute of General Medical Sciences Chapter 3: Drugs From Nature, Then and Now Medicines By Design in PDF Chapter 3: Drugs From Nature, Then and Now Long before the first towns were built, before written language was invented, and even before plants were cultivated for food, the basic human desires to relieve pain and prolong life fueled the search for medicines. No one knows for sure what the earliest humans did to treat their ailments, but they probably sought cures in the plants, animals, and minerals around them. Got It? Nature's Medicine Cabinet Times have changed, but more than half of the world's population still relies entirely on plants for medicines, and plants supply the active ingredients of most traditional medical products. Plants have also served as the starting point for countless drugs on the market today. Researchers generally agree that natural products from plants and other organisms have been the most consistently successful source for ideas for new drugs, since nature is a master chemist.

Drug discovery scientists often refer to these ideas as "leads," and chemicals that have desirable properties in lab tests are called lead compounds. Relatively speaking, very few species of living things on Earth have actually been seen and named by scientists. Many of these unidentified organisms aren't necessarily lurking in uninhabited places. A few years ago, for instance, scientists identified a brand-new species of millipede in a rotting leaf pile in New York City's Central Park, an area visited by thousands of people every day. Scientists estimate that Earth is home to at least 250,000 different species of plants, and that up to 30 million species of insects crawl or fly somewhere around the globe. Equal numbers of species of fungi, algae, and bacteria probably also exist. Despite these vast numbers, chemists have tested only a few of these organisms to see whether they harbor some sort of medically useful substance. Pharmaceutical chemists seek ideas for new drugs not only in plants, but in any part of nature where they may find valuable clues. This includes searching for organisms from what has been called the last unexplored frontier: the seawater that blankets nearly three-quarters of Earth.

Back to Top Natural Cholesterol-Buster Sap from the guggul tree, a species native to India, contains a substance that may help fight heart disease. Having high cholesterol is a significant risk factor for heart disease, a leading cause of death in the industrialized world. Pharmacology research has made major strides in helping people deal with this problem. Scientists Michael Brown and Joseph Goldstein, both of the University of Texas Southwestern Medical Center at Dallas, won the 1985 Nobel Prize in physiology or medicine for their fundamental work determining how the body metabolizes cholesterol. This research, part of which first identified cholesterol receptors, led to the development of the popular cholesterol-lowering "statin" drugs such as Mevacor® and Lipitor®. New research from pharmacologist David Mangelsdorf, also at the University of Texas Southwestern Medical Center at Dallas, is pointing to another potential treatment for high cholesterol. The "new" substance has the tongue-twisting name guggulsterone, and it isn't really new at all. Guggulsterone comes from the sap of the guggul tree, a species native to India, and has been used in India's Ayurvedic medicine since at least 600 B.C.

to treat a wide variety of ailments, including obesity and cholesterol disorders. Mangelsdorf and his coworker David Moore of Baylor College of Medicine in Houston, Texas, found that guggulsterone blocks a protein called the FXR receptor that plays a role in cholesterol metabolism, converting cholesterol in the blood to bile acids. According to Mangelsdorf, since elevated levels of bile acids can actually boost cholesterol, blocking FXR helps to bring cholesterol counts down. Back to Top Cancer Therapy Sees the Light Some forms of cancer can be treated with photodynamic therapy, in which a cancer-killing molecule is activated by certain wavelengths of light. JOSEPH FRIEDBERG A novel drug delivery system called photodynamic therapy combines an ancient plant remedy, modern blood transfusion techniques, and light. Photodynamic therapy has been approved by the Food and Drug Administration to treat several cancers and certain types of age-related macular degeneration, a devastating eye disease that is the leading cause of blindness in North America and Europe. Photodynamic therapy is also being tested as a treatment for some skin and immune disorders. The key ingredient in this therapy is psoralen, a plant-derived chemical that has a peculiar property: It is inactive until exposed to light.

Psoralen is the active ingredient in a Nile-dwelling weed called ammi. This remedy was used by ancient Egyptians, who noticed that people became prone to sunburn after eating the weed. Modern researchers explained this phenomenon by discovering that psoralen, after being digested, goes to the skin's surface, where it is activated by the sun's ultraviolet rays. Activated psoralen attaches tenaciously to the DNA of rapidly dividing cancer cells and kills them. Photopheresis, a method that exposes a psoralen-like drug to certain wavelengths of light, is approved for the treatment of some forms of lymphoma, a cancer of white blood cells. Back to Top Ocean Medicines Marine animals fight daily for both food and survival, and this underwater warfare is waged with chemicals. As with plants, researchers have recognized the potential use of this chemical weaponry to kill bacteria or raging cancer cells. Scientists isolated the first marine-derived cancer drug, now known as Cytosar-U®, decades ago. They found this chemical, a staple for treating leukemia and lymphoma, in a Caribbean sea sponge. In recent years, scientists have discovered dozens of similar ocean-derived chemicals that appear to be powerful cancer cell killers. Researchers are testing these natural products for their therapeutic properties.

Yondelis is an experimental cancer drug isolated from the marine organism Ecteinascidia turbinata . PHARMAMAR For example, scientists have unearthed several promising drugs from sea creatures called tunicates. More commonly known as sea squirts, tunicates are a group of marine organisms that spend most of their lives attached to docks, rocks, or the undersides of boats. To an untrained eye they look like nothing more than small, colorful blobs, but tunicates are evolutionarily more closely related to vertebrates like ourselves than to most other invertebrate animals. One tunicate living in the crystal waters of West Indies coral reefs and mangrove swamps turned out to be the source of an experimental cancer drug called ecteinascidin. Ken Rinehart, a chemist who was then at the University of Illinois at Urbana-Champaign discovered this natural substance. PharmaMar, a pharmaceutical company based in Spain, now holds the licenses for ecteinascidin, which it calls Yondelis™, and is conducting clinical trials on this drug. Lab tests indicate that Yondelis can kill cancer cells, and the first set of clinical studies has shown that the drug is safe for use in humans.

Further phases of clinical testing—to evaluate whether Yondelis effectively treats soft-tissue sarcomas (tumors of the muscles, tendons, and supportive tissues)— and other types of cancer—are under way. A poison produced by the cone snail C. geographus has become a powerful new pain medicine. K.S. MATZ Animals that live in coral reefs almost always rely on chemistry to ward off hungry predators. Because getting away quickly isn't an option in this environment, lethal chemical brews are the weaponry of choice for these slow-moving or even sedentary animals. A powerful potion comes from one of these animals, a stunningly gorgeous species of snail found in the reefs surrounding Australia, Indonesia, and the Philippines. The animals, called cone snails, have a unique venom containing dozens of nerve toxins. Some of these venoms instantly shock prey, like the sting of an electric eel or the poisons of scorpions and sea anemones. Others cause paralysis, like the venoms of cobras and puffer fish.

Pharmacologist Baldomero Olivera of the University of Utah in Salt Lake City, a native of the Philippines whose boyhood fascination with cone snails matured into a career studying them, has discovered one cone snail poison that has become a potent new pain medicine. Olivera's experiments have shown that the snail toxin is 1,000 times more powerful than morphine in treating certain kinds of chronic pain. The snail-derived drug, named Prialt™ by the company (Elan Corporation, plc in Dublin, Ireland) that developed and markets it, jams up nerve transmission in the spinal cord and blocks certain pain signals from reaching the brain. Scientists predict that many more cone snail toxins will be drug leads, since 500 different species of this animal populate Earth. Penicillium mold colony inhibits the growth of bacteria (zig-zag smear growing on culture dish). Led by the German scientist Paul Ehrlich, a new era in pharmacology began in the late 19th century. Although Ehrlich's original idea seems perfectly obvious now, it was considered very strange at the time.

He proposed that every disease should be treated with a chemical specific for that disease, and that the pharmacologist's task was to find these treatments by systematically testing potential drugs. The approach worked: Ehrlich's greatest triumph was his discovery of salvarsan, the first effective treatment for the sexually transmitted disease syphilis. Ehrlich discovered salvarsan after screening 605 different arsenic-containing compounds. Later, researchers around the world had great success in developing new drugs by following Ehrlich's methods. For example, testing of sulfur-containing dyes led to the 20th century's first "miracle drugs"—the sulfa drugs, used to treat bacterial infections. During the 1940s, sulfa drugs were rapidly replaced by a new, more powerful, and safer antibacterial drug, penicillin—originally extracted from the soil-dwelling fungus Penicillium Prospecting Biology? The cancer drug Taxol originally came from the bark and needles of yew trees. Are researchers taking advantage of nature when it comes to hunting for new medicines? Public concern has been raised about scientists scouring the world's tropical rainforests and coral reefs to look for potential natural chemicals that may end up being useful drugs.

While it is true that rainforests in particular are home to an extraordinarily rich array of species of animals and plants, many life-saving medicines derived from natural products have been discovered in temperate climates not much different from our kitchens and backyards. Many wonder drugs have arisen from non-endangered species, such as the bark of the willow tree, which was the original source of aspirin. The antibiotic penicillin, from an ordinary mold, is another example. Although scientists first found the chemical that became the widely prescribed cancer drug Taxol® in the bark of an endangered species of tree called the Pacific yew, researchers have since found a way to manufacture Taxol in the lab, starting with an extract from pine needles of the much more abundant European yew. In many cases, chemists have also figured out ways to make large quantities of rainforest- and reef-derived chemicals in the lab (see Back to Top Tweaking Nature Searching nature's treasure trove for potential medicines is often only the first step. Having tapped natural resources to hunt for new medicines, pharmaceutical scientists then work to figure out ways to cultivate natural products or to make them from scratch in the lab.

Chemists play an essential role in turning marine and other natural products, which are often found in minute quantities, into useful medicines. In the case of Yondelis, chemist Elias J. Corey of Harvard University in Boston, Massachusetts, deciphered nature's instructions on how to make this powerful medicinal molecule. That's important, because researchers must harvest more than a ton of Caribbean sea squirts to produce just 1 gram of the drug. By synthesizing drugs in a lab, scientists can produce thousands more units of a drug, plenty to use in patients if it proves effective against disease. Scientists are also beginning to use a relatively new procedure called combinatorial genetics to custom-make products that don't even exist in nature. Researchers have discovered ways to remove the genetic instructions for entire metabolic pathways from certain microorganisms, alter the instructions, and then put them back. This method can generate new and different "natural" products. Back to Top Toxicogenetics: Poisons and Your Genes Just as your genes help determine how you respond to certain medicines, your genetic code can also affect your susceptibility to illness. Why is it that two people with a similar lifestyle and a nearly identical environment can have such different propensities to getting sick?

Lots of factors contribute, including diet, but scientists believe that an important component of disease risk is the genetic variability of people's reactions to chemicals in the environment. On hearing the word "chemical," many people think of smokestacks and pollution. Indeed, our world is littered with toxic chemicals, some natural and some synthetic. For example, nearly all of us would succumb quickly to the poisonous bite of a cobra, but it is harder to predict which of us will develop cancer from exposure to carcinogens like cigarette smoke. Toxicologists are researchers who study the effects of poisonous substances on living organisms. One toxicologist, Serrine Lau of the University of Texas at Austin, is trying to unravel the genetic mystery of why people are more or less susceptible to kidney damage after coming into contact with some types of poisons. Lau and her coworkers study the effects of a substance called hydroquinone (HQ), an industrial pollutant and a contaminant in cigarette smoke and diesel engine exhaust. Lau is searching for genes that play a role in triggering cancer in response to HQ exposure.

Her research and the work of other so-called toxicogeneticists should help scientists find genetic "signatures" that can predict risk of developing cancer in people exposed to harmful carcinogens. Back to Top Is It Chemistry or Genetics? Regardless of the way researchers find new medicines, drug discovery often takes many unexpected twists and turns. Scientists must train their eyes to look for new opportunities lurking in the outcomes of their experiments. Sometimes, side trips in the lab can open up entirely new avenues of discovery. Take the case of cyclosporine, a drug discovered three decades ago that suppresses the immune system and thereby prevents the body from rejecting transplanted organs. Still a best-selling medicine, cyclosporine was a research breakthrough. The drug made it possible for surgeons to save the lives of many critically ill patients by transplanting organs. But it's not hard to imagine that the very properties that make cyclosporine so powerful in putting a lid on the immune system can cause serious side effects, by damping immune function too much. Years after the discovery of cyclosporine, researchers looking for less toxic versions of this drug found a natural molecule called FK506 that seemed to produce the same immune-suppressing effects at lower doses.

The researchers found, to their great surprise, that cyclosporine and FK506 were chemically very different. To try to explain this puzzling result, Harvard University organic chemist Stuart Schreiber (then at Yale University in New Haven, Connecticut) decided to take on the challenge of figuring out how to make FK506 in his lab, beginning with simple chemical building blocks. Schreiber succeeded, and he and scientists at Merck & Co., Inc. (Whitehouse Station, New Jersey) used the synthetic FK506 as a tool to unravel the molecular structure of the receptor for FK506 found on immune cells. According to Schreiber, information about the receptor's structure from these experiments opened his eyes to consider an entirely new line of research. Schreiber reasoned that by custom-making small molecules in the lab, scientists could probe the function of the FK506 receptor to systematically study how the immune system works. Since then, he and his group have continued to use synthetic small molecules to explore biology. Although Schreiber's strategy is not truly genetics, he calls the approach chemical genetics, because the method resembles the way researchers go about their studies to understand the functions of genes.

In one traditional genetic approach, scientists alter the "spelling" (nucleotide components) of a gene and put the altered gene into a model organism—for example, a mouse, a plant, or a yeast cell—to see what effect the gene change has on the biology of that organism. Chemical genetics harnesses the power of chemistry to custom-produce any molecule and introduce it into cells, then look for biological changes that result. Starting with chemicals instead of genes gives drug development a step up. If the substance being tested produces a desired effect, such as stalling the growth of cancer cells, then the molecule can be chemically manipulated in short order since the chemist already knows how to make it. Blending Science The herb feverfew (bachelor's button) contains a substance called parthenolide that appears to block inflammation. These days, it's hard for scientists to know what to call themselves. As research worlds collide in wondrous and productive ways, the lines get blurry when it comes to describing your expertise. Craig Crews of Yale University, for example, mixes a combination of molecular pharmacology, chemistry, and genetics.

In fact, because of his multiple scientific curiosities, Crews is a faculty member in three different Yale departments: molecular, cellular, and developmental biology; chemistry; and pharmacology. You might wonder how he has time to get anything done. He's getting plenty done—Crews is among a new breed of researchers delving into a growing scientific area called chemical genetics (see main text). Taking this approach, scientists use chemistry to attack biological problems that traditionally have been solved through genetic experiments such as the genetic engineering of bacteria, yeast, and mice. Crews' goal is to explore how natural products work in living systems and to identify new targets for designing drugs. He has discovered how an inflammation-fighting ingredient in the medicinal herb feverfew may work inside cells. He found that the ingredient, called parthenolide, appears to disable a key process that gets inflammation going. In the case of feverfew, a handful of controlled scientific studies in people have hinted that the herb, also known by its plant name "bachelor's button," is effective in combating migraine headaches, but further studies are needed to confirm these preliminary findings.

Back to Top Testing...I, II, III To translate pharmacology research into patient care, potential drugs ultimately have to be tested in people. This multistage process is known as clinical trials, and it has led researchers to validate life-saving treatments for many diseases, such as childhood leukemia and Hodgkin's disease. Clinical trials, though costly and very time-consuming, are the only way researchers can know for sure whether experimental treatments work in humans. Scientists conduct clinical trials in three phases (I, II, and III), each providing the answer to a different fundamental question about a potential new drug: Is it safe? Does it work? Is it better than the standard treatment? Typically, researchers do years of basic work in the lab and in animal models before they can even consider testing an experimental treatment in people. Importantly, scientists who wish to test drugs in people must follow strict rules that are designed to protect those who volunteer to participate in clinical trials. Special groups called Institutional Review Boards, or IRBs, evaluate all proposed research involving humans to determine the potential risks and anticipated benefits. The goal of an IRB is to make sure that the risks are minimized and that they are reasonable compared to the knowledge expected to be gained by performing the study.

Clinical studies cannot go forward without IRB approval. In addition, people in clinical studies must agree to the terms of a trial by participating in a process called informed consent and signing a form, required by law, that says they understand the risks and benefits involved in the study. Phase I studies test a drug's safety in a few dozen to a hundred people and are designed to figure out what happens to a drug in the body—how it is absorbed, metabolized, and excreted. Phase I studies usually take several months. Phase II trials test whether or not a drug produces a desired effect. These studies take longer—from several months to a few years—and can involve up to several hundred patients. A phase III study further examines the effectiveness of a drug as well as whether the drug is better than current treatments. Phase III studies involve hundreds to thousands of patients, and these advanced trials typically last several years.Many phase II and phase III studies are randomized, meaning that one group of patients gets the experimental drug being tested while a second, control group gets either a standard treatment or placebo (that is, no treatment, often masked as a "dummy" pill or injection).

Also, usually phase II and phase III studies are "blinded"—the patients and the researchers do not know who is getting the experimental drug. Finally, once a new drug has completed phase III testing, a pharmaceutical company can request approval from the Food and Drug Administration to market the drug. Pharmacology and Its Branches - Get Med Edu logos meaning "study or reasoning" Branches of Pharmacology Pharmacology can be divided into various branches. Its major branches are given below: Pharmacokinetics Pharmacokinetics is what our body does to a drug. It includes the study of absorption, distribution, metabolism and excretion of drugs and their relationship with the onset, duration, and intensity of the drug effect. Pharmacodynamics Pharmacodynamics is what a drug does to our body. It includes the study of mechanism of action of a drug, the relation between drug concentration and its therapeutic effect and the physical and chemical effects of drugs on our body, parasites and micro-organisms. Therapeutics/Pharmacotherapeutics It the branch of pharmacology in which we apply the pharmacological information together with the knowledge of disease, for the prevention and cure of disease.

Chemotherapy In this branch, we study the treatment of diseases by chemicals that kill the cells, especially those of micro-organisms and neoplastic cells. Toxicology In this branch, we study the adverse effects of drugs on the body. It deals with the symptoms, mechanisms, treatment and detection of poisoning caused by different chemical substances. For toxicology, main criterion is the dose. A medicine in high dose can be a poison while a poison in low dose can be a medicine. Clinical Pharmacology It is the use of drugs in the clinical routine. Main objectives are: to maximize the effect of drug to minimize the adverse effects to generate optimum data for use of drugs, and to promote the usage of evidence-based medicine Pharmacy It is the branch of pharmacology that deals with the study of preparation, compounding and dispensing of different drugs. Pharmacognosy It deals with the study of properties of drugs in crude or unprepared forms. Pharmacoeconomics It is the study of economic factors regarding the cost of drug therapies, including their impact on healthcare system and society. Pharmacogenetics/Pharmacogenomics It deals with the study of genetic variations that cause difference in drug response among different individuals.

Pharmacoepidemiology It deals with the study of effects of drugs on a large population. It includes trial studies on healthy and diseased individuals and collecting the opinion of physicians prescribing a drug. Comparative Pharmacology It deals with the comparison of different drugs of same or different uses. Posology It deals with the study of dosage of drugs. Animal Pharmacology It deals with different properties of drugs in animals. SHARE: Department of Pharmacology and Experimental Therapeutics Department of Pharmacology and Experimental Therapeutics /pharmacy/ Frederic and Mary Wolfe Center Room 274 pharmacology.dept@utoledo.edu Department of Pharmacology and Experimental Therapeutics Pharmacology is the science that deals with the origin, nature, chemistry, effects, and uses of drugs; it includes pharmacokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. Pharmacology addresses the study of drugs in all aspects: their properties and reactions with relation to therapeutic value, as well as the discovery, biological/physiological effects other than therapeutic effects (adverse reactions and side effects), and uses. This science also addresses the body’s effects on drugs, including absorption, distribution, metabolism and excretion of drugs.

About the Department of Pharmacology & Experimental Therapeutics The Department of Pharmacology seeks to integrate both basic and applied research in the pharmaceutical sciences into the academic programs in order to provide students with the information they need to be successful in the challenging fields of pharmacy and the pharmaceutical industry. The Department of Pharmacology contributes to the training of students in the Doctor of Pharmacy and B.S. in Pharmaceutical Sciences (BSPS) programs, with extensive training offered to students in the Pharmacology/Toxicology major of the B.S. in Pharmaceutical Sciences program. The department also offers a master's in Pharmaceutical Sciences with a concentration in Pharmacology/Toxicology and a Ph.D. in Experimental Therapeutics. Departmental courses cover a broad range of disciplines, including a series of pharmacology, toxicology, and pharmacokinetics/toxicokinetics courses and many other courses in experimental therapeutics at the graduate level. The department’s faculty members have research interests in neuro- and molecular pharmacology, drug metabolism, polycystic kidney disease, zebrafish as a model for drug testing, and toxicology.

Contact Us Pharmacology | List of High Impact Articles | PPts | Journals | Videos Pharmacology is the science that deals with the origin, nature, chemistry, effects, and uses of drugs; it includes pharmacognosy , pharmacokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. Related journals of Pharmacology International Journal of Pharmacology and Technology, Asian Journal of Biochemical and Pharmaceutical Research, American Society for Biochemistry and Molecular Biology, American Journal of Bio-pharmacology Biochemistry and Life Sciences, Behavioural Pharmacology, Biochemical Pharmacology, Canadian Journal of Physiology and Pharmacology Pharmacology

Question: What is the science that deals with the origin, nature, chemistry, effects and use of drugs?
Answer: Pharmacology