An approach to drug abuse, intoxication and withdrawal.

The symptomatic effects of drug abuse are a result of alterations in the functioning of the following neurotransmitters or their receptors: acetylcholine, dopamine, gamma-aminobutyric acid, norepinephrine, opioids and serotonin. Anticholinergic drugs antagonize acetylcholine receptors. Dissociative drugs affect all transmitter sites. Opiates act on both opioid and adrenergic receptor sites. Psychedelic drugs stimulate serotonin release, and sedative-hypnotic drugs potentiate the gamma-aminobutyric acid receptor. Specific signs and symptoms are associated with the neurotransmitters and receptors affected by each drug class. By recognizing symptomatic changes related to particular neurotransmitters and their receptors, family physicians can accurately determine the drug class and intervene appropriately to counteract drug-induced effects.