Some central effects of repeated treatment with fluvoxamine.

We investigated the effect of repeated treatment with fluvoxamine, a selective serotonin uptake inhibitor, on behavioral effects of dopaminomimetics and methoxamine and on the animal behavior in the "behavioral despair" test. A repeated treatment with fluvoxamine (twice daily for 14 days) potentiated in mice and in rats (weaker) the amphetamine-induced hyperactivity. The hyperactivity induced by nomifensine in mice remained unaffected by fluvoxamine. The stimulation of locomotor activity by intracerebroventricularly administered methoxamine was not affected by repeated treatment with fluvoxamine. Given three times fluvoxamine had no effect on the immobilization time in the "behavioral despair" test in rats. The results indicate that fluvoxamine given repeatedly acts differently than citalopram, another selective serotonin uptake inhibitor, and differs also from other antidepressant drugs.