Questions & Answers

What else might you want to know about PrEP

How well does PrEP work?

When doesn’t PrEP work?

How do I make PrEP work best?

What do trans guys need to think about when taking PrEP?

So do I still need to wear condoms?

What if I forget to take my pill?

I’m on PrEP and my body feels like crap. What should I do?

I’ve got other health stuff going on. Is it safe for me to go on PrEP?

How long do guys take PrEP?

I’ve heard that some guys take PrEP for a couple of days before, during, and after hooking up. Does that work?

What happens if I become HIV-positive while I’m on PrEP?

How well does PrEP work?

It works really well in preventing HIV, as long as you are taking it as prescribed by your doctor and going for regular follow-up visits with your doctor. PrEP is almost completely effective if you take it every day, and can be less effective if you miss a few doses. It doesn’t protect you from other STIs. Take a look at prepfacts.org and prepwatch.org for more details about the different studies that have been done.

When doesn’t PrEP work?

PrEP’s effectiveness is directly related to taking the pill at around the same time everyday. If you take it daily and never miss a dose, it works amazingly well. If you miss a few doses, it works less well. It also takes about a week before you’re fully protected. If you’re going off PrEP, it should be taken for four weeks after the last time you had condomless sex.

It’s rare, but some rare strains of HIV are resistant to PrEP. In 2015, there was one case where a guy on PrEP ended up acquiring one of these drug-resistant strains of HIV even though he took PrEP regularly.

How do I make PrEP work best?

PrEP works great in combination with other strategies. Using condoms when you’re on PrEP may seem unnecessary, but makes the possibility of HIV transmission virtually zero. This is especially important if a guy isn’t taking PrEP consistently. Likewise, when guys on PrEP have sex with guys with undetectable viral loads, the possibility of HIV transmission is essentially zero. Condoms also protect against other STIs.

What do trans guys need to think about when taking PrEP?

There hasn’t been enough research to say for sure how effective PrEP is in trans men when compared with other guys. If you’re thinking about using PrEP and you’re having front hole sex, it needs to be taken consistently for three weeks before it is effective in the vagina.

There is some evidence showing that Truvada takes longer to reach maximum drug levels in vaginal tissues compared to rectal tissues, and that drug levels are lower in vaginal tissues. This suggests that daily dosing of oral PrEP may be more important for people having vaginal sex to maintain sufficient drug levels to help prevent HIV infection.

Research is needed to determine if the hormones used by trans guys have a relationship to PrEP.

So do I still need to wear condoms?

It is recommended that PrEP be used in addition to condoms, so you can ensure that the chance of HIV transmission while taking PrEP remains extremely low , especially if pills are missed. Neither PrEP or condoms are 100% effective, so using both can be a great way of staying HIV-negative. At the same time, PrEP is recommended for people who are not using condoms, so it’s important to know that PrEP still works really well if a condom is not used, as long as it’s used consistently.

If you want to decrease the chance of getting some other STIs like chlamydia or gonorrhea, condoms provide that protection. Check out our page about combining sexual health strategies to figure out which ones will work best for you.

What if I forget to take my pill?

If it happens, take your next pill as soon as you remember. Don’t bother taking two pills at a time to make up for it though.

I’m on PrEP and my body feels like crap. What should I do?

This could mean a few things and it’s best if you follow up with your doctor right away. If you have flu-like symptoms, like a fever, a headache, joint pain or a sore throat, it could mean be a sign of possible HIV infection. If you have stomach aches or nausea, these could be side effects of the drug. If they’re really bad, or haven’t gone away after a while, talk to a doctor.

I’ve got other health stuff going on. Is it safe for me to go on PrEP?

PrEP can cause bone mineral density and kidney problems. If you’ve had any related issues, you should talk to your doctor to figure out if there are ways to minimize the impact of PrEP.

PrEP can be a complicated issue if the person using it also has a hepatitis B infection. It is especially important that you inform your doctor that you have hep B and talk about what that means.

It’s also important to tell them about any meds, including vitamins and supplements, that you take regularly, or any other health stuff they might not know about you.

How long do guys take PrEP?

Taking daily PrEP looks different for everybody. Some people might take it for a couple months when they feel it is appropriate, or others might take it over a longer-term. What’s important is that it takes about a week of taking PrEP daily to be effective, and you’d need to take PrEP for 28 days after having sex without condoms.

I’ve heard that some guys take PrEP for a couple of days before, during, and after hooking up. Does that work?

While it’s always a good idea to plan ahead to prevent HIV, PrEP works best as a long-term routine and not as an occasional thing. Some people think that short-term or casual PrEP treatments work, which some people call “disco dosing” or “condom holidays.” In terms of timing, it takes about a week of taking Truvada daily to be effective, and you’d need to take PrEP for 28 days after having sex without condoms.

There has been a study that showed that guys taking PrEP for a few days before and after sex reduced transmissions. However, most people in the study were having sex often, so this “short-term” PrEP usage might actually have been similar to daily PrEP in practice.

Currently in Canada, PrEP is approved for daily use in combination with other strategies. If you want PrEP to work best, getting a prescription in the long-term is a more stable and dependable option.

What happens if I become HIV-positive while I’m on PrEP?

If you become HIV-positive, you’ll have to stop taking PrEP and start a new treatment for HIV infection. Take a look at the Pozitively Healthy resource for more information about connecting to care and looking out for your health.