Fluvoxamine and clomipramine in the treatment of cataplexy.

Fluvoxamine 25-200 mg daily and clomipramine 25-200 mg daily were given for separate three week periods to 18 subjects with narcolepsy and cataplexy. Both drugs improved cataplexy but not narcolepsy. Fluvoxamine was less active than clomipramine, but both drugs abolished cataplexy in individual subjects. Gastrointestinal side effects prevented treatment with fluvoxamine in five subjects. All patients completed the clomipramine phase of the trial, but two men complained of delayed ejaculation. Fluvoxamine is a more potent inhibitor of 5-hydroxytryptamine (5-HT) reuptake in some systems, but not in others. It is therefore uncertain whether the greater anticataplectic effect of clomipramine is due to a greater inhibition of 5-HT reuptake or to other mechanisms.