Pharmacological profile of dextrorphan

Dextrorphan (CAS 125-73-5) is the active metabolite of the antitussive agent dextromethorphan (CAS 125-71-3). The activity of dextromethorphan, its specific pharmacology, acute toxicity and general pharmacology in respect to the central nervous system were investigated in comparison to dextromethorphan. The studies showed that dextrorphan exerts an antitussive activity comparable to the one of dextromethorphan, but a better tolerability and a lower toxicity. These results suggest to use dextrorphan instead of its precursor dextromethorphan in therapy.

Comparative pharmacokinetics of oral dextromethorphan and dextrorphan in the rabbit

The pharmacokinetics of dextromethorphan (CAS 125-71-3) and its metabolite dextrorphan (CAS 125-73-5) was compared. The drugs were administered orally at the same molar dose of 0.085 mmol/kg. Plasma levels of dextromethorphan, dextrorphan, and metabolites 3-hydroxymorphinan and 3-methoxymorphinan were determined by HPLC with fluorimetric detection. Dextromethorphan was rapidly and extensively metabolized and the plasma profiles of dextrorphan, administered directly or as metabolite of dextromethorphan, were similar. The concentrations of 3-hydroxymorphinan were higher after dextromethorphan than dextrorphan. 3-Methoxymorphinan was detectable only 60 and 120 min after dextromethorphan. This work proposes the therapeutic use of dextrorphan instead of its precursor dextromethorphan.