DRUG INTERACTIONS Drug interactions
Codeine: In patients receiving MAO inhibitors, an initial small test dose is advisable to allow observation of any excessive narcotic effects or MAOI interaction.
Promethazine:
CNS depressants – Promethazine 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, 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.
Epinephrine – Because of the potential for promethazine to reverse epinephrine’s vasopressor effect, epinephrine should NOT be used to treat hypotension associated with promethazine overdose.
Anticholinergics – Concomitant use of other agents with anticholinergic properties should be undertaken with caution.
Monoamine oxidase inhibitors (MAOI) – Drug interactions, including an increased incidence of extrapyramidal effects, have been reported when some MAOI and phenothiazines are used concomitantly.
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CONTRAINDICATIONS
Codeine is contraindicated in patients with a known hypersensitivity to the drug.
Promethazine is contraindicated in comatose states, and in individuals known to be hypersensitive or to have had an idiosyncratic reaction to promethazine or to other phenothiazines.
The combination of promethazine hydrochloride and codeine phosphate is contraindicated in pediatric patients less than 16 years of age, because the combination may cause fatal respiratory depression in this age population.
Antihistamines and codeine are both contraindicated for use in the treatment of lower respiratory tract symptoms, including asthma.
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