Many doctors and activists see immense promise for such preventive use of Truvada, and are campaigning hard to raise awareness of it as a crucial step toward reducing new HIV infections, which now total about 50,000 a year in the U.S. Recent efforts range from think-tank forums and informational websites to a festive event at a New York City bar featuring popular drag queens.
Yet others - despite mounting evidence of Truvada's effectiveness - say such efforts are reckless, tempting some condom users to abandon that layer of protection and exposing them to an array of other sexually transmitted infections aside from HIV.
"If something comes along that's better than condoms, I'm all for it, but Truvada is not that," said Michael Weinstein, president of the AIDS Healthcare Foundation. "Let's be honest: It's a party drug."
Even as gay-rights organizations celebrate collective progress in the fight to legalize same-sex marriage, the less-publicized Truvada debate has fueled bitter divisions within the gay community. Some who use the drug say they've felt shamed by some who don't, and there's now a lively backlash by users and their allies, including promotion of a "Truvada Whore" T-shirt.
"The discussion can torch emotions like a flame-thrower on a fuel depot," wrote Steve Ramos of the Dallas Voice as the gay-oriented publication reported on the debate in March.
Truvada, produced by California-based Gilead Sciences, has been around for a decade, serving as one of the key drugs used in combination with others as the basic treatment for people who have the AIDS-causing virus HIV. However, the drug took on a more contentious aspect in 2012 when the Food and Drug Administration approved it for pre-exposure prophylaxis, or PrEP - in other words, for use to prevent people from getting sexually transmitted HIV in the first place.
Since then, critics have warned that many gay men won't heed Truvada's once-a-day regimen and complained of its high cost - roughly $13,000 a year. Truvada's proponents say most insurance plans - including Medicaid programs - now cover prescriptions for it, and they cite studies showing that the blue pill, if taken diligently, can reduce the risk of getting HIV by more than 90 percent.
Dr. Demetre Daskalakis, medical director of the ambulatory HIV program at New York's Mount Sinai Hospital, served on the FDA panel that recommended approving Truvada for preventive purposes and is among many doctors who hope that doubts about it fade.
"For folks who are having a significant amount of unprotected sex, it's a slam dunk - not only giving them protective medicine, but engaging them in testing, a whole package of regular health care," he said.
Yet Daskalakis says that out of his large clientele, only about 25 men are taking Truvada for prevention.
"There's some interesting social pushback," he said. "I've spoken to some of my patients who'd totally be candidates but are hesitant to do it. They don't want to be labeled as people on the drug because there's a social stigma."
Daskalakis is dismayed by groups like the Los Angeles-based AIDS Healthcare Foundation - one of the country's leading HIV/AIDS service providers - which suggest that prescribing Truvada for prevention means condoning condomless sex.
"I find some of that opposition irresponsible," Daskalakis said. "If some men don't want to use condoms, they won't. You have to deal with it by acknowledging that sometimes unprotected sex happens, and you can still prevent HIV infections."
To date, preventive use of Truvada appears to be limited, due partly to misgivings among some gay men and partly to lack of awareness.
According to Gilead, 1,774 people starting using Truvada for prevention between January 2011 and March 2013 - nearly half of them women. The company said more recent figures aren't available, but health officials in several cities said they see no signs of a major surge in usage.
"Out of our thousands of patients, we have about 20 on PrEP," said Dr. Robert Winn, medical director at Philadelphia's Mazzoni Center, which serves many gay clients.
"Many ask about it, few take it," Winn said. "The number one reason for that gap is the commitment of having to take it every day."
Weinstein, the AIDS Healthcare Foundation leader, takes heart from the low usage figures, saying they bear out his reservations about Truvada. He says he's undeterred by criticism of his insistence that condomless sex - even in the Truvada era - should be discouraged among gay men with multiple partners.
"There's an element in the gay community that espouses 'anything goes,' that is for sexual freedom and not giving an inch," he said. "But demonizing me or AHF isn't going to shut us up."
Another Truvada skeptic is Richard Weinmeyer, a research associate with the American Medical Association's Ethics Group. In an article in February in Bioethics Forum, Weinmeyer - expressing his personal views - argued that preventive use of Truvada could encourage sexual irresponsibility.
"Personal responsibility for one's actions has simply been thrown out the window in a community in which we are too often concerned about stigma and moral judgment," he wrote. "We dare not speak against the reckless behavior of others because we wring our hands over the omnipresent worry that we will shame one another."
The article drew some harsh online criticism; readers called it "puritanical" and "fear-mongering." But Weinmeyer raised a topic that's a visceral part of the debate - the concept of gay-on-gay "shaming" in which men using Truvada as PrEP are stigmatized.
New York psychotherapist Damon Jacobs, an enthusiastic Truvada user since 2011, has encountered the shaming syndrome as he encourages more gay men to learn about the drug's preventive capabilities. Since co-founding an informational web site called PrEP-o-licious.org, Jacobs says he's heard from men distressed by reactions they faced after broaching the possibility of taking Truvada.
"They'd email me about the names they were called - the 'Truvada whore' syndrome," Jacobs said. "They'd talk with their friends about responsible condomless sex, and they'd get shamed. They'd get seen as a slut."
The U.S. Centers for Disease Control and Prevention offers extensive information about PrEP on its web site.
"Strong research evidence indicates that PrEP, when used consistently, is safe and effective for reducing the risk of acquiring HIV sexually," it says.
However, Jacobs says other wings of the medical establishment should be more active in disseminating that message, both to gay men and to doctors.
"A lot of doctors are still under the belief that if they give their patients PrEP, they'll go out and have condomless sex," Jacobs said. "What they don't understand is that gay men are already doing that."
At the Fenway Institute in Boston - which specializes in gay, lesbian and transgender health - many doctors initially had misgivings about PrEP, but have overcome them, according to Dr. Kenneth Mayer, the institute's medical research director.
"There definitely were apprehensions at the beginning - would it increase risk-taking behavior, would people take it regularly," Mayer said. "More recently, the questions are not whether it's a good idea, but the optimal way to provide it, and which patients are the best candidates."
"I don't have an issue with people voicing concerns about it, but we have proof it works," said Mayer, who hopes high-level federal officials get more involved in the public discussion.
Another challenge is raising awareness of PrEP in black communities with high HIV infection rates.
"We have young minority men becoming infected at disproportionately alarming rates, and now we have something that could avert this," said Lynnette Ford of GMHC, a New York City AIDS service organization. "But there's not a lot of information out there in communities that need it most."
Demetre Daskalakis, the Mount Sinai doctor, said the Truvada debate recalls the way birth control was viewed in some quarters in the 1960s - as an accessory to promiscuity.
"Anyone who takes Truvada, someone is looking at them and saying they're licentious," Daskalakis said. "When this becomes more normalized, we'll be fine."