The benefits of erectile dysfunction drugs are well- documented. They may be double-edged as well.

In a study published Tuesday in Annals of Internal Medicine, researchers analyzed pharmacy data for men over 40 who had received a prescription for an erectile dysfunction drug. We'll let them sum it up:

"Men who use ED drugs have higher rates of STDs, particularly HIV infection, both in the year before and after use of these drugs."

Here's the abstract from the STD study, the journal's information for patients and the pertinent-facts WebMD story: Men on ED Drugs Get More STDs. (Reuters cast it this way: Viagra-popping seniors lead the pack for STDs. ... That's right: "Seniors.")

As for what erectile dysfunction drugs can -- and can't -- do, please refer to this Viagra (sildenafil) information from rxlist.com. It's quite blunt, stating near the top of the page:

"Use of this drug does not protect against sexually transmitted diseases (e.g., HIV, hepatitis B, gonorrhea, syphilis). Practice "safe sex" such as using latex condoms. Consult your doctor or pharmacist for more details."

The information on Levitra (vardenafil) and Cialis (tadalafil) say the same thing.