Amphetamine Interactions

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Antidepressants, tricyclic:

Amphetamines may enhance the activity of tricyclic or sympathomimetic agents; using d-amphetamine with desipramine or protriptyline and possibly other tricyclics can cause striking and sustained increases in the concentration of d-amphetamine in the brain; cardiovascular effects can be potentiated.

Acidifying agents:

Gastrointestinal acidifying agents (guanethidine, reserpine, glutamic acid HCl, ascorbic acid (Vitamin C), fruit juices, etc.) lower absorption of amphetamines.

Urinary acidifying agents: (ammonium chloride, sodium acid phosphate, Vitamin C, and others) increase urinary excretion thereby lowering blood levels of amphetamines.

Alkalinizing agents:

        Gastrointestinal alkalinizing agents (sodium bicarbonate, etc.) increase absorption of amphetamines.

        Urinary alkalinizing agents (acetazolamide, some thiazides) decrease urinary excretion and, in this way, increase blood levels.

Adrenergic blockers: Adrenergic blockers are inhibited by amphetamines.

MAO inhibitors: A variety of neurological toxic effects and malignant hyperpyrexia can occur, sometimes with fatal results.

Antihistamines: Amphetamines may counteract the sedative effect of antihistamines.

Antihypertensives: Amphetamines may antagonize the hypotensive effects of Antihypertensives.

Chlorpromazine and Haldol: Chlorpromazine blocks dopamine and norepinephrine reuptake, thus inhibiting the central stimulant effects of amphetamines and can be used to treat amphetamine poisoning.

Lithium carbonate: The anti-obesity and stimulating effects of amphetamines may be inhibited by lithium carbonate.

Meperidine: Amphetamines potentiate the analgesic effect of meperidine.

Norepinephrine: Amphetamines enhance the adrenergic effect of norepinephrine.

Phenytoin: Amphetamines may delay intestinal absorption of phenytoin; co-administration of phenytoin may produce a synergistic anticonvulsant action.

Propoxyphene: In most cases of propoxyphene overdosage, amphetamine CNS stimulation is possible, and fatal convulsions can occur.