Cream May Be Alternative to Viagra
Monday September 28 2:15 PM EDT
LAURAN NEERGAARD AP Medical Writer
WASHINGTON (AP) - Researchers are turning anti-impotence pills and injected medicines into rub-on creams and gels - part of a broader effort to make many drugs safer and easier to use by literally dissolving them through the skin.
Early testing shows the impotence cream Topiglan is a leading candidate in this effort to give patients targeted relief for many ailments, with fewer side effects.
''It's a no-brainer,'' said Dr. Irwin Goldstein of Boston University, a urologist leading studies of the impotence cream who expects many of today's medicines eventually to be applied to the skin. ''It has a lot of use in lots of drugs.''
Topiglan needs more studies, Goldstein cautions, and is not for sale. But it might become a good alternative for men who can't take the popular impotence pill Viagra - which sometimes causes dangerous side effects in men with heart disease, Goldstein said. Or, severely impotent men could use both treatments together.
Topiglan is made from a longtime impotence drug called alprostadil that works very well, but has a problem: It must either be injected into the penis or inserted as a suppository, both painful.
A company based in Lexington, Mass., MacroChem Corp., invented a ''skin enhancer,'' a chemical that lets potent drugs seep through the skin by opening a temporary window in skin's normally impenetrable barriers. That means patients can get much-higher drug doses delivered straight to the site of disease - with fewer side effects.
By adding its skin enhancer, MacroChem created a cream that patients can rub onto the end of the penis.
Goldstein gave 114 moderately impotent men either a dummy cream, a low dose of Topiglan or a high dose. Inside a doctor's office, they used the creams and then watched an adult movie or used a stimulator. The excitement alone helped 20 percent of placebo patients get an erection adequate for intercourse, but high-dose Topiglan helped 69 percent.
The only side effect was a warm sensation on the penis.
MacroChem is now talking with 10 major drug manufacturers bidding for rights to sell Topiglan, said chief executive Alvin Karloff.
But MacroChem hopes to treat more than impotence. Furthest along in testing:
-Ibuprofen gel. Ibuprofen is the over-the-counter painkiller popular in such brands as Advil that helps millions battle arthritis and other aches. But regular use and high doses also can cause ulcers because ibuprofen first travels through the stomach before ever reaching a sore joint. Combining ibuprofen with the skin enhancer created a gel that penetrates straight into the ache, proving 80 percent effective in one study, without any ulcer risk because it never hits the stomach.
-Anti-fungus toenail polish. Patients with toenail fungus infections spend months swallowing medicines that can harm their livers before ever reaching their toes. Adding the skin enhancer let MacroChem turn fungicides into a polish that penetrates just the spot that needs treating.
Yet, topical drugs for anything other than skin-deep conditions are difficult to create. The barely visible square lines on skin are dead cells tightly bound together by lipids impervious to water and other substances, forming a sealed barrier.
Earlier attempts at skin-enhanced topical drugs largely failed, said Food and Drug Administration pharmacologist Tom McGinnis. They were greasy, and controlling the dosage was difficult.
Then companies successfully tried patches, which trap enough heat onto one spot that skin's lipids become wet and let drugs slip inside. Today, patients get hormone treatment and fight motion sickness with patches. ''It doesn't run all over the place, it doesn't get on your clothing,'' McGinnis said.
But patches also can irritate the skin, cost more to make than the actual drug and aren't powerful enough for many medicines, Karloff said. MacroChem's skin enhancer is a hydrocarbon that creates a temporary chemical reaction with the lipids, briefly liquifying skin cells so drugs can penetrate. Once it dries, the skin's seal returns intact.
''You only do this where there's an apparent advantage'' over pills and injections, Karloff explained. ''Our goal is to treat ... where the problem exists, rather than dose the whole body.'' |
