What is PREP?

Pre Exposure Prophylaxis (PrEP) is a medication taken daily to prevent HIV.  It is a useful and effective tool to prevent HIV in HIV-negative individuals who are at high risk of acquiring the virus.  Some examples of high-risk individuals include men who have sex with men, injection drug users and heterosexual men or women that have a substantial number of sexual partners or a sexual partner with a known history of HIV.

PrEP most commonly consists of an antiretroviral medication called Truvada.  Truvada is two antiretroviral medications in one that work to prevent HIV infection by blocking an enzyme that’s used by the virus to make copies of itself.  PrEP is gaining in popularity as an effective method to prevent HIV however it does not protect against any other sexually transmitted diseases such as syphilis, gonorrhea and/or chlamydia and for this reason it is important to always use protection.

How effective is PrEP?

Studies have shown that when taken daily as prescribed, PrEP with Truvada is 92% - 99% effective at preventing transmission of HIV.  According to the iPrEx Study PrEP is 99% effective for people who take the medication 7 days per week and 96% effective for people who take the medication 4 days per week.  Until there is more data on non-daily use, the FDA recommends taking PrEP daily to achieve the highest level of protection.  It generally takes about 1-2 weeks for the medication to reach adequate levels of protection in the body and it is advised to use condoms during this particular time.

How do I get PrEP?

PrEP is a medication that is available by prescription from your doctor.  At your initial appointment the doctor will gather some information and take your blood to ensure you do not have any pre-existing conditions.  At your follow up, you will review the blood test results and receive your prescription.

Are there side effects to PrEP?

Most people have very few if any side effects from PrEP.  Some people may initially experience some side effects of nausea, vomiting, fatigue and dizziness that usually resolve by the end of the first month of taking the medication. 

Some clinical trials have documented a small proportion of people with mild to moderate changes in blood tests relating to kidney function.  These changes were primarily seen in people with pre-existing kidney conditions and support the CDC’s Truvada PrEP guidelines which recommend laboratory monitoring at least every six months.   

Overall, PrEP with Truvada is safe for most people but may affect kidney function in some people with pre-existing conditions.  Regular follow up with your doctor every 2-3 months allows for ongoing monitoring of kidney function and is important to promptly catch any problems that may occur.

How do I stop PrEP?

You may continue PrEP for as long as needed.  It is considered a prevention strategy similar to birth control in that you take the pills for the time period you need the protection.  You can stop PrEP at any time at least 28 days after a possible exposure.   


Post Exposure Prophylaxis

Post Exposure Prophylaxis or PEP is the term used for antiretroviral medication(s) taken shortly after being exposed to HIV to prevent viral transmission of the disease.  The medication(s) are usually taken for 28 days after exposure and require frequent monitoring to check for any development of infection.  It is generally used on an emergency basis and is most effective when started within 36 hours of exposure but may be used up to 72 hours after initial exposure.