In case you think of Viagra as a condom in pill form, the warning that Pfizer slips into each package is sure to set you straight: “Viagra does not prevent the transmission of STDs.” But for Jeffrey Klausner, MD, a feisty public-health official who is worried about San Francisco’s rising rate of HIV and other STDs, the little blue pill’s red flag is “a useless, senseless statement.” Useless, that is, to users of Viagra, though not, the doctor claims, to Pfizer, which “was clever enough to put one over on the FDA.”

Why is Klausner kvetching? Data from New York, Florida and the CDC point to Viagra as a significant risk factor for STD transmission. In San Francisco, where the prescription for erectile dysfunction is known as Vitamin V, studies show that users are two to three times more likely to have a diagnosed STD. Among gay men, extended extensions, especially when mixed with crystal meth, make for what epidemiologists call the multiplier effect, or marathon unsafe group sex—the same conditions that facilitated the early-’80s wildfire spread of HIV.

But according to Pfizer’s Mariann Caprino, no credible evidence exists to back Klausner’s claim that the blockbuster Viagra puts the V in HIV. Repeating to POZ comments she made to the Wall Street Journal, she also contended that recreational users who engage in high-risk behavior “aren’t going to read labels or heed warnings.”

Whether a company is responsible for the abuse of its product is not a question for the contentious Klausner. In an earlier bout with Merck over its ads for HIV meds, Klausner prevailed, but only with FDA help. This time the FDA is a no-show, though the National Association of STD Directors supports a Viagra health warning. “Under the Bush administration, the role of the FDA seems to be to facilitate commerce, not to be a public health agency.” Klausner says. “Pfizer and this country don’t really care about the health of gay men.” Klausner may appeal next to the (famously gay-unfriendly)U.S. attorney general to make Viagra a controlled substance, a move that would prevent Pfizer from marketing directly to consumers.

While this prospect may not scare the pants off Pfizer, it might prove unsettling to Congress—and not because Bob Dole, a former senator, has made millions as Vitamin V’s pitchman. “Personnel at Pfizer, ”Klausner says, “have told me that more than half of the U.S. Congress likely takes Viagra.” Caprino denies that anyone at Pfizer had authority to make such a statement.