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Rx only
DESCRIPTION
Each 5 mL (one teaspoonful), for oral administration contains: Dextromethorphan hydrobromide 15 mg; promethazine hydrochloride 6.25 mg. Alcohol 7%.
Inactive Ingredients: Ascorbic acid, citric acid, D&C yellow #10, FD&C yellow #6, menthol, methylparaben, orange pineapple flavor, propylene glycol, propylparaben, purified water, saccharin sodium, sodium benzoate, sodium citrate and sucrose.
Dextromethorphan hydrobromide is a salt of the methyl ether of the dextrorotatory isomer of levorphanol, a narcotic analgesic. It is chemically designated as 3-methoxy-17-methyl-9α, 13α, 14α-morphinan hydrobromide monohydrate. Dextromethorphan hydrobromide occurs as white crystals sparingly soluble in water and freely soluble in alcohol. It has a molecular weight of 370.32, a molecular formula of C18H25NO•HBr•H2O, and the following structural formula:
Promethazine is a racemic compound. Promethazine hydrochloride, a phenothiazine derivative, is chemically designated as 10H-Phenothiazine-10-ethanamine, N,N, α-trimethyl-monohydrochloride.
Promethazine hydrochloride occurs as a white to faint yellow, practically odorless, crystalline powder which slowly oxidizes and turns blue on prolonged exposure to air. It is soluble in water and freely soluble in alcohol. It has a molecular weight of 320.88, a molecular formula of C17H20N2S•HCI, and the following structural formula:
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CLINICAL PHARMACOLOGY
Dextromethorphan:
Dextromethorphan is an antitussive agent and, unlike the isomeric levorphanol, it has no analgesic or addictive properties.
The drug acts centrally and elevates the threshold for coughing. It is about equal to codeine in depressing the cough reflex. In therapeutic dosage dextromethorphan does not inhibit ciliary activity.
Dextromethorphan is rapidly absorbed from the gastrointestinal tract and exerts its effect in 15 to 30 minutes. The duration of action after oral administration is approximately three to six hours. Dextromethorphan is metabolized primarily by liver enzymes undergoing O-demethylation, N-demethylation, and partial conjugation with glucuronic acid and sulfate. In humans, (+)-3-hydroxy-N-methyl-morphinan, (+)-3-hydroxymorphinan, and traces of unmetabolized drug were found in urine after oral administration.
Promethazine:
Promethazine is a phenothiazine derivative which differs structurally from the antipsychotic phenothiazines by the presence of a branched side chain and no ring substitution. It is thought that this configuration is responsible for its relative lack (1/10 that of chlorpromazine) of dopamine antagonist properties.
Promethazine is an H1 receptor blocking agent. In addition to its antihistaminic action, it provides clinically useful sedative and antiemetic effects.
Promethazine is well absorbed from the gastrointestinal tract. Clinical effects are apparent within 20 minutes after oral administration and generally last four to six hours, although they may persist as long as 12 hours. Promethazine is metabolized by the liver to a variety of compounds; the sulfoxides of promethazine and N-demethylpromethazine are the predominant metabolites appearing in the urine.
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