A BRITISH company is developing a drug to help overcome the sexual side
effects of Prozac. At least a third of people taking such antidepressants have
difficulty attaining orgasm or suffer a loss of libido.
Although a drug like Viagra can increase blood flow, it doesn鈥檛 change desire
and arousal, says John Hutchison of Vernalis, a company in Reading, Berkshire,
that is co-developing the new drug, codenamed VML 670, with Prozac鈥檚
manufacturer, Eli Lilly. VML 670, by contrast, activates a receptor in the brain
called 5-HT1A, which is known to be linked with sexual arousal.
In tests on rodents, Vernalis showed that VML 670 increases the animals鈥� sex
drive. Males mounted receptive females sooner and ejaculated more quickly. 鈥淚t
took less time for them to get together,鈥� says Hutchison.
Advertisement
Next year, Vernalis plans to see if the drug helps patients taking a class of
antidepressants known as selective serotonin re-uptake inhibitors, which
includes Prozac. SSRIs flood the brain with the neurotransmitter serotonin,
which brings calmness and contentment.
Unfortunately, this also seems to swamp the 5-HT1A receptor,
affecting arousal and orgasm in both sexes. The drug ecstasy, which also
increases serotonin levels, can have similar effects.
Vernalis hopes VML 670 will compensate for the effects of SSRIs, and has
already tested its safety on healthy people. But Hutchison doesn鈥檛 expect the
drug to amplify the sex drive of people not taking antidepressants and warns
them against trying it. 鈥淥ur healthy volunteers reported no difference in
arousal,鈥� he says. 鈥淭hat鈥檚 good news, because we don鈥檛 want to alter normal sex
诲谤颈惫别.鈥�
Nonetheless, he expects that regulatory agencies will want VML 670 and Viagra
to be tested together in volunteers to be sure there are no ill effects.