Promethazine drug interactions

List of drug interactions
CNS depressants Epinephrine Anticholinergics Monoamine oxidase inhibitors

CNS depressants
Promethazine HCl Syrup Plain may increase, prolong, or intensify the sedative action of other central-nervous-system depressants such as alcohol, sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers; therefore, such agents should be avoided or administered in reduced dosage to patients receiving Promethazine HCl. When given concomitantly with Promethazine HCl Syrup Plain, the dose of barbiturates should be reduced by at least one-half, and the dose of narcotics should be reduced by one-quarter to one-half. Dosage must be individualized. Excessive amounts of Promethazine HCl relative to a narcotic may lead to restlessness and motor hyperactivity in the patient with pain; these symptoms usually disappear with adequate control of the pain. Return to top

Epinephrine
Because of the potential for Promethazine HCl Syrup Plain to reverse epinephrine’s vasopressor effect, epinephrine should NOT be used to treat hypotension associated with Promethazine HCl Syrup Plain overdose. Return to top

Anticholinergics
Concomitant use of other agents with anticholinergic properties should be undertaken with caution. Return to top

Monoamine oxidase inhibitors
Drug interactions, including an increased incidence of extrapyramidal effects, have been reported when some MAOI and phenothiazines are used concomitantly. This possibility should be considered with Promethazine HCl Syrup Plain. Return to top