Q. I have tried Viagra for erectile difficulty, but it gives me headaches. I’ve heard there are some other sexual enhancers available or in testing. What can you tell me about these?
A. One potential competitor for Viagra is a pill called Vasomax. This is a new application of the established drug phentolamine, which used to be injected directly into the penis. It works by blocking blood-vessel constriction, making it easier for the blood vessels to expand. When taken orally, it affects the whole body. Trials showed that 42 percent of men with mild erectile dysfunction develop better erections with this drug. Its effects in men with severe erectile dysfunction are less satisfying. Side effects include headaches, low blood pressure, fast heartbeat and nasal congestion. As of this writing in mid-2000, this agent is working its way through trials required in the FDA approval process.
Another promising agent is Uprima, or oral apomorphine, which should be released soon. The mechanism of action appears to be located in brain centers that enhance the erection and sexual experience. This fast-acting drug might be used in combination with others like Viagra. Known side effects are limited to nausea, which might go away after the first few uses.
Bayer Pharmeceuticals also has a new agent in drug studies; this is a selective phosphodiesterase inhibitor that should have effects similar to Viagra, but hopefully with fewer side effects. However, it is expected to achieve a response only in about 30 percent of the men who use it.