Metabolism of fenfluramine to norfenfluramine in guinea-pigs.

After injection of fenfluramine into guinea-pigs, the N-dealkylated metabolite norfenfluramine was present in brain at higher concentrations and persisted longer than the parent drug, fenfluramine. Contrary to a claim in previous literature, the guinea-pig does metabolize fenfluramine to norfenfluramine, hence the ability of fenfluramine to cause acute and long-term depletion of brain 5-hydroxytryptamine in this species does not prove that fenfluramine, instead of nonfenfluramine, can produce these effects.