A synthetic morphine derived from levorphanol . Dextromethorphan HBr salt is also in use.
They have the same anti-tussive activity as other morphine derivatives. And it is almost similar in depressing the cough as codeine.
It is used for cough in minor throat and bronchial irritation such as that in common cold. It is most effective in reducing chronic non-productive cough.
Administration and dosage:
It is administered orally and its lozenges are also used for adults. The usual dosage of Dextromethorphan HBr is 10-20 mg every 4 hours for adults and children above 6 years.
1. It is absorbed rapidly from GI tract.
2. Its onset of action is 12-30 minutes.
3. Its duration of action is 2-6 hours.
Very rare but nausea and GI tract disturbances may occur sometimes.