Dextromethorphan Polistirex

Dextromethorphan Hydrobromide is a cough suppressant. It acts centrally, on the cough center in the medulla. Its structure is related to morphine, but it has no pain-relieving action and in general causes little sedation. Addiction has not been seen even after rather large doses were given for a prolonged period. The medicine is absorbed rapidly from the GI tract and begins to work 15 to 30 minutes after it is taken by mouth.

Polistirex forms a matrix around the Dextromethorphan particles. This slows how fast the Dextromethorphan dissolves in the gastrointestinal tract, so it enters the bloodstream gradually and over a longer time. With the extended release suspension, the action lasts 12 hours.

The liver metabolizes Dextromethorphan Hydrobromide extensively. It is excreted in the urine as unchanged Dextromethorphan and as de-methylated metabolites, including Dextrophan, which has some cough suppressant activity. Urinary excretion of the parent drug and metabolites accounts for up to 50% of the ingested dose over 24 hours. About 8% of the dose is excreted unchanged in the urine over the first 6 hours.