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10: Drugs
Your Health Today, 9th Edition
© McGraw Hill LLC
What Is a Drug?
Drug: substance other than food that affects the
structure or function of the body through its chemical
action.
• Psychoactive drugs change brain chemistry and alter
consciousness, perception, mood, and thought (intoxication).
Drug of abuse: medical drug used for nonmedical
(recreational) purposes, or a drug that has no medical
uses.
Substance: drug of abuse, a medication, or a toxin; the
term is used interchangeably with drug.
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Types of Drugs
Drugs are classified in several different ways.
Legal drugs include:
• Medication prescribed by physicians.
• Over-the-counter (OTC) medications.
• Herbal remedies.
Pharmaceutical drugs are developed for medical
purposes, whether over-the-counter or prescription.
Illicit drugs are generally viewed as harmful and are
unlawful to possess, manufacture, sell, or use.
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Who Uses?
Patterns of Illicit Drug Use
Rates of illicit drug use vary by age, gender, race and
ethnicity, education, employment status, and region.
In 2017 an estimated 1 in 9 individuals in the U.S. aged 12
and older had used illicit drugs in the past month.
• Almost 8% of adolescents, 24.2% of young adults, and 9.5% of
those older than 26.
The most commonly used drug is marijuana.
There is also a substantial misuse of psychotherapeutics
(prescription-type drugs).
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Drug Misuse and Abuse 1
Drug misuse: use of prescription drugs for purposes
other than those for which they were prescribed or in
greater amounts than prescribed, or the use of
nonprescription drugs or chemicals for purposes other
than those intended by the manufacturer.
Drug abuse: use of a substance in amounts, situations,
or a manner such that it causes problems, or greatly
increases the risk of problems, for the user or for
others.
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Drug Misuse and Abuse 2
The National Institute of Drug Abuse (NIDA) defines
any use of an illicit drug as drug abuse and defines
addiction as a chronic, relapsing brain disease
characterized by compulsive drug seeking and use,
despite harmful consequences.
Tolerance is reduced sensitivity to the effects of
the drug.
Withdrawal symptoms are uncomfortable feelings
when drug use stops.
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Routes of Administration
Most drugs are taken orally.
Injection: involves a hypodermic syringe to deliver drug
into the bloodstream.
• Intravenous injection.
• Intramuscular injection.
• Subcutaneous injection.
Inhalation: smoking or huffing.
Application to mucous membranes. (snorting)
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Table 10.1 Routes of Administration
Route Time to Reach
Brain Drug Example Potential
Adverse Effects
Inhalation:
smoking and
huffing
7 to 10 seconds Marijuana, crack
cocaine, tobacco,
inhalants
Irritation of lungs; liver and
kidney damage; hearing loss;
vomiting
Injection Intravenous,
15 to 30 seconds;
intramuscular,
3 to 5 minutes;
subcutaneous,
5 to 7 minutes
Heroin, cocaine,
methamphetamine
Danger of overdose;
collapsed veins; infection at
injection site; blood infection;
transmission of HIV, hepatitis
C, and other pathogens
Mucus
membranes:
snorting
3 to 15 minutes Cocaine, heroin,
methamphetamine
Irritation or destruction of
tissue; difficulty controlling
dose
Oral ingestion:
eating, drinking
20 to 30 minutes Alcohol, pills Vomiting
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Factors Influencing the
Effects of Drugs
Characteristics of the drug:
• Chemical properties of the drug and its actions.
• Interactions with other drugs.
Characteristics of the person:
• Age, gender, body weight and mass, physical condition.
• Mood.
• Experience with the drug, expectations.
Characteristics of the situation or environment:
• At home or surrounded by strangers.
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Effects of Drugs on the Brain 1
Many addictive drugs act on neurons in three brain
structures:
• Ventral tegmental area (VTA) in the midbrain.
• Nucleus accumbens.
• Prefrontal cortex.
Neurons in these structures form a pathway referred to
as the pleasure and reward circuit.
Addictive psychoactive drugs activate and cause a
surge in levels of dopamine and associated feelings
of pleasure.
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Effects of Drugs on the Brain 2
All or nearly all addictive drugs operate via the pleasure
and reward circuit.
Some also operate via additional mechanisms.
• For example the opioids have a structure similar to that of
endorphins, which block pain when the body undergoes stress.
Individuals trying to recover from addiction must
overcome:
• Altered brain chemistry;
• Drug-related memories; and
• Impaired impulse control.
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Drugs of Abuse
Drugs of abuse are usually classified as:
• Stimulants;
• Depressants;
• Opioids;
• Hallucinogens;
• Inhalants; and
• Cannabinoids.
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Central Nervous System Stimulants
Stimulants: drugs that speed up activity in the brain
and sympathetic nervous system.
• Effects similar to the “fight-or-flight” reaction.
• May stimulate movement, fidgeting, and talking, and produce
intense feelings of euphoria and create a sense of well-being.
Examples:
• Cocaine.
• Amphetamines.
• MDMA (Ecstasy).
• Bath salts.
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Central Nervous System Depressants
Depressants slow down activity in the brain and
sympathetic nervous system.
• Can be deadly if misused, especially when mixed
with alcohol.
• CNS depressants carry a high risk of dependence.
Examples:
Barbiturates and hypnotics.
Anti-anxiety drugs (benzodiazepines).
• Rebound effect: when a person stops using a drug and
experiences symptoms worse than those before taking
the drug.
Rohypnol and GHB (gamma hydroxybutyrate). 15
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Opioids 1
Opioids: natural and synthetic derivatives of opium.
• Currently prescribed as pain relievers, anesthetics,
antidiarrheal agents, and cough suppressants.
• Produce feelings of pleasure and block pain.
Examples:
• Morphine.
• Heroin.
• Synthetic opioids (OxyContin, Vicodin, Demerol, Dilaudid,
Percocet, Percodan and Fentanyl).
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Opioids 2
With low doses, opioid users experience euphoria
followed by drowsiness.
At high dosages, users can experience depressed
respiration, loss of consciousness, coma, and death.
Opioids have a high potential for dependence.
The nonmedical use and abuse of prescription drugs,
particularly opioids and benzodiazepines (used to treat
anxiety), is a serious public health problem.
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Hallucinogens and Dissociative Drugs
Hallucinogens: alter perceptions and thinking,
intensifying and distorting visual and auditory
perceptions and producing hallucinations; also known
as psychedelics.
• Alter perceptions and thinking in characteristic ways.
• Intensify and distort visual and auditory perceptions and
produce hallucinations.
Examples:
• LSD (lysergic acid diethylamide).
• Phencyclidine (PCP) and ketamine.
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Inhalants
Inhalants: breathable chemical vapors that alter
consciousness, producing a state that resembles
drunkenness.
The active ingredients are all dangerously powerful
toxins and carcinogens.
The most significant negative effect for chronic users is
widespread and long-lasting brain damage.
Examples:
• Paint thinner, gasoline, glue, and spray-can propellant.
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Cannabinoids 1
Marijuana is the most widely used illicit drug in the
United States.
• Derived from the hemp plant, Cannabis sativa.
• Active ingredient is delta-9-tetrahydrocannabinol (THC).
Researchers have found that THC has a variety of
effects on the brain, perhaps accounting for some
impairments in problem solving and decision making.
• Use also increases the likelihood of breathing problems.
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Cannabinoids 2
Many people support medical uses of marijuana.
• Treatment for glaucoma, for the pain and nausea of cancer
and chemotherapy, and for weight loss associated with AIDS.
Opponents argue legalization implies approval and will
encourage abuse of all drugs.
Like alcohol, marijuana affects the skills required to
drive a car safely.
It is legal for medical use in 23 states; and legal for
nonmedical adult use in 11 states plus D.C.
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Emerging Drugs of Abuse
The newest set of drugs being experimented with
include:
• Anabolic steroids—performance enhancing drugs.
• Synthetic cannabinoids such as K2 and Spice.
• “Syrup,” “Purple Drank,” “Sizzurp,” and “Lean”—all
prescription-strength cough syrup containing codeine and
promethazine mixed with soda.
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Drug Treatment Programs
Treatment programs range from hospital-based
inpatient programs to self-help/mutual-help groups
such as Narcotics Anonymous (NA).
Treatment is a long-term process, often marked by
relapses.
Programs are more successful when they last
at least 3 months.
Matching services to individual needs is critical.
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Harm-Reduction Strategies
These are based on the idea that completely
eliminating substance use is futile and efforts should
focus on reducing the associated harm.
• Needle exchange programs.
• Drug substitutes, such as methadone for heroin addicts.
• Safe injection spaces.
• Controlled availability.
• Medicalization.
• Decriminalization.
Opponents argue these are forms of drug legalization.
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