Let’s face it, guys: HIV can be a real, er, downer. Many men with HIV, for reasons ranging from emotional stress to testosterone depletion to med side effects, have trouble getting it up downstairs. Now (in case there’s no TV in your cave and you’re dumb to the buzz), there’s help for what’s politely called “erectile dysfunction.”

But if you’re thinking of adding Viagra blue to your already-colorful palette of meds, proceed with caution. First, some causes of impotence are treatable by other methods, so taking this drug may simply mask those causes and postpone their resolution. That’s why experts advise getting a full medical exam before jumping on the Viagra bandwagon. And for those who choose to take the plunge, be aware of two warnings from the Gay and Lesbian Medical Association (GLMA) and AIDS Treatment News: 1) Certain AIDS drugs may not mix well with the boner pill, or may intensify its widely celebrated effects—if you can imagine that; and 2) if you take Viagra and do poppers—those little bottles of nitrate or nitrite inhalants popular among gay men and others to enhance sexual arousal—you could experience a sudden, severe and potentially dangerous drop in blood pressure.

Viagra and AIDS drugs. The interaction between Viagra and many medications widely used by PWAs hasn’t been studied. But we do know that the drug is metabolized by the liver’s p450 enzyme system. Several drugs inhibit p450, including protease inhibitors (especially ritonavir [Norvir]), delavirdine (Rescriptor) and such antibiotics as clarithromycin, azithromycin, ketoconazole and itraconazole. Whether Viagra hinders the effects of anti-HIV drugs is unknown, though company officials say it probably doesn’t, based on test-tube studies.

When Viagra and these drugs are combined, they may cause an elevation in Viagra’s concentration in the blood. “Medical providers should therefore consider starting these patients at the lowest possible dose of Viagra: 25 mg,” according to GLMA. The drug’s package insert notes that higher blood levels “may increase both the efficacy and incidence of adverse events.” Those “events” can include facial flushing, headaches and visual abnormalities. There’s even a possibility that some anti-HIV drugs might decrease Viagra blood levels, according to Richard Jefferys of the AIDS Treatment Data Network.

Kiyoshi Kuromiya, director of the Critical Path AIDS Project in Philadelphia, is among those advising caution. “There just hasn’t been enough research on drug interactions to say these combinations are safe,” he says, “particularly if you have pre-existing liver problems or use higher than the recommended Viagra dosage.”

Viagra and poppers. Like Viagra, poppers dilate blood vessels and together the two could result in a sudden blood-pressure plummet, which could be serious or even fatal. “Medical providers and patients should discuss all recreational drug use, especially the use of poppers or other forms of inhaled nitrates, prior to prescribing Viagra,” warned GLMA.

Concern over this volatile mix prompted Pfizer officials to call treatment advocates around the coun-try in April. Pfizer spokesperson Mariann Caprino says that a warning about “nitrates” appears in Viagra’s FDA-approved package insert, but added, “You can’t use words like poppers in your insert” because of the inhalants’ quasi-legal status: Nitrates are federally controlled angina drugs, and nitrites are legal solvents that are illegal to inhale in many states. Caprino says Pfizer won FDA approval in May of sales materials that “spell out poppers loud and clear.” But Kuromiya reported, “Sales reps from the company are marketing the drug to the gay male community without warning about this danger.”

And the impotence drug seems quite popular in HIV positive gay circles. Howard Grossman, a Manhattan AIDS doc, writes eight to ten prescriptions a day, but warns about poppers and monitors patients for adverse effects.

So far, groups like Gay Men’s Health Crisis haven’t received any bad reports. “You can have sex without poppers,” observes GMHC spokesperson Stephen Soba. “Besides, with Viagra, isn’t that gilding the lily just a little bit?”