What to Expect When You're on PrEP

Maybe you've had the conversation with your doctor and gotten started on PrEP, or maybe you're still thinking about it. Studies have shown that the use of Truvada as pre-exposure prophylaxis, or PrEP, to prevent HIV infection, is safe and effective. But there are some things you should know about the experience of being on PrEP.

You will take your medication every day. Daily use of Truvada has been shown to be 99 percent effective in preventing HIV infection, whether or not a condom is used. There's still a high level of protection if you don't take it every day, but daily dosing is optimal.

People taking Truvada for PrEP should take one tablet a day, with or without food, according to Gilead, the company that makes the drug. Truvada is a combination of two HIV-fighting drugs -- it contains 200 milligrams of Emtriva (generic name emtricitabine) and 300 milligrams of Viread (tenofovir disoproxil fumarate).

If you miss a dose -- say, if you usually take your pill at night and you forget -- taking it the next morning is fine. But health experts say there's no need to double-dose to make up for missed doses. You also don't need to take your Truvada at the same time every day, but having a set time may help you remember to take it.

You will be tested for HIV at least every three months. PrEP is designed to help you stay HIV-negative. It's important to establish that you're HIV-negative before starting a PrEP regimen; if you already have HIV and start taking Truvada, you may become resistant to the drug. Truvada is used to treat HIV as well as prevent it, but for treatment it's always used in combination with other drugs. Let your doctor know if you have flu-like symptoms, such as fever, joint or muscle aches, headache, or sore throat, as that can indicate a new HIV infection that some tests can miss.

Also to help you stay negative, health care professionals recommend that you use other safer-sex tools, such as condoms, in addition to PrEP -- although, of course, we know that people don't always use condoms consistently or properly, and they do break.

You may experience some side effects, and you may need to see your doctor more often than usual when you first go on PrEP so he or she can monitor you for side effects. The most common side effects of Truvada when used for PrEP are headache, abdominal pain, and weight loss. If these don't go away quickly or become severe, contact your physician. But don't stop taking your Truvada without asking the doc.

The more serious side effects include an excess of lactic acid in the blood, serious liver problems, new or worsening kidney problems (and possibly kidney failure), and worsening of hepatitis B infection. If you have serious kidney trouble, you should not be taking Truvada, so your doctor may want to check your kidney function before you start your regimen. You can read more about the symptoms of these health problems here and here. Again, contact your doctor if you have any of these symptoms, but don't stop taking your medication without an OK.

And as you should do when starting any medication, tell your doctor what health problems you have. Women who are pregnant or breast-feeding should tell the physician about that, or if they plan to become pregnant.

Another thing you should do when starting any med: Tell your doctor what other prescription or over-the-counter meds, vitamins, or herbal supplements you take, and also any recreational drugs or alcoholic beverages you consume. Truvada should not be taken in combination with certain other HIV drugs. These include the meds that make up Truvada -- Emtriva and Viread -- and other meds that contain them, such as Atripla, Complera, and Stribild. You also shouldn't take Truvada with drugs containing lamivudine, an HIV drug marketed under the brand name Epivir. If you're HIV-negative, you're most likely not taking these, but you should have the information. And if your partner is positive, no, you can't trade drugs with each other -- different ones are right for different people, and Truvada is the only one to date approved by government regulators for HIV prevention. You should also not take Truvada with Hepsera, a drug used to treat hepatitis B.

And good advice for everyone, on PrEP or not: Take care of your health in general. We all know we should get proper nutrition, rest, and exercise, and reduce the emotional stress in our lives, but we don't always do so. But starting a PrEP regimen is as good a reminder as any to keep our bodies and minds healthy.