Drowsiness
* also plays a role in crashes attributed to other causes.
* can be a symptom of overdosage.
* can be severe in some patients, especially in the elderly
  - reduce reaction time almost as much as drinking
  - result, leading to possible problems with driving or handling dangerous machinery
* cause of accidents and impaired performance in work and study.
* common side effect of many antihistamines.
* is also a common phenomenon
  - common and disappears with time
  - common, and there is often confusion and impairment of consciousness
  - far different from the impaired driving demonstrated in the Iowa study
  - more common in elderly and debilitated patients and in patients receiving high doses
* is one of the greatest killers in interstate highway driving
  - most common side effects of trazodone
  - sign of carbon monoxide poisoning
  - quite common after a painful injury, especially a bump on the head
  - related to bewilderment-erring
  - the major side effect in most patients
* is the signal that sleep onset is seconds away
  - to get off the road
* kills on highways.
* makes driving more difficult by dulling concentration and slowing reaction time.
* occurs occasionally during initial treatment with some phenothiazines
  - when cells undergo moderate hyperpolarizations
* often disappears with increased dose.
* symptom of overdose.
* usually goes away within a few days.
* well-known side affect of the drug, which otherwise suppresses seasickness.

### drug:

Addictive drug
* All addictive drugs have two things in common.
* Most addictive drugs change the effect of neurotransmitters on neurons.
* activate the brain's reward systems.
* are bad, true, but tobacco is addictive, and so is booze.
* can cause serious problems for the fetus and for the baby when it is born
  - so rapidly and dramatically change the brain that the drugs literally take over
* enhance the reinforcing impact of such electrical stimulation.
* have three defining characteristics.
* increase levels of the chemical neurotransmitter dopamine.

### drug:

Anaesthetic
* are medicine
  - medicines or drugs which stop a person from having feelings in their body
* go back a long way in history.
+ Cocaine, Cocaine as a legal medicine: Illegal drugs
  * Dentists in countries like Australia sometimes use cocaine in dental operations, as an anaesthetic. Anaesthetics are medicines or drugs which stop a person from having feelings in their body. Doctors, surgeons, and dentists use anaesthetics when they are doing operations, so that the patient will not feel pain. Dentists put the cocaine on the patient's mouth so that the patient will not feel pain in their mouth during the operation.

Analgesic drug
* act in various ways on the peripheral and central nervous systems.
* reduce pain and are generally categorized as narcotics and non-narcotics.

### drug:

Anesthetic
* Many anesthetics consist of nothing more than intramuscular ketamine and a secure airway
  - exist as racemates, or pairs of optically active enantiomers
* Most anesthetics can cause low blood pressure.
* Some anesthetics have side effects.
* are another concern for pet owners
  - depressant drugs that produce a partial or total loss of the sense of pain
  - more selective for inhibition of A d and C fibers than are analgesics
  - next, and hydrocarbons appear to cause the most liver damage
  - substances that block nerves so that they can no longer transmit pain signals
  - unique drugs in pharmacology
  - useful for sedating such fish, and to reduce the metabolic activity
* block pain by blocking the transmission of nerve signals.
* differ from alcohol in their duration of action and elimination kinetics.
* have effects on breathing, heart action and blood pressure.
* increase cytosolic calcium in mononuclear cells from normal and MH-susceptible patients.
* wear off at different rates.