To lead a healthy life, it’s always important to practice safe sex. Barrier methods of contraception are probably something everyone knows or has learned through some form of media in their lives. Though alone they are essential to prevent the spread of most sexually transmitted infections (STIs), barrier methods need to be combined with a medical method—called PrEP—to protect yourself from human immunodeficiency virus (HIV).

What is PrEP?

PrEP, or pre-exposure prophylaxis, is nothing short of a magic bullet to keep you safe from HIV. The most widely preferred form of PrEP is a pill that you can take orally once a day. The other method is a long-acting shot given to you monthly by a healthcare provider. Only the pill is approved for PrEP in Canada, and it is also preferable as you can take it on your own and there may be fewer chances of allergic reactions compared to the shot.

The PrEP pill and how it works

Truvada is the World Health Organization-approved medicine for PrEP. It contains emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF), which are combination antiretroviral drugs (as HIV is a retrovirus) that reduce the risk of acquiring HIV infection. Scientifically, FTC and TDF belong to a class of drugs called nucleoside analogs.

HIV enters the body through contact with other HIV-positive people through sexual activity. Once inside, HIV quickly infects other cells in the body. It takes over the cells and directs them to use an enzyme to start replicating. The process can continue for a long time until the virus establishes a permanent infection. Truvada works by slowing down or halting the replication process, ultimately preventing the virus from causing infection.

The dose strength for Truvada is 200 mg/300 mg Tablets: 200 mg of FTC and 300 mg of TDF.

Generic formulations of Truvada are easily available now and cost much less than the brand medication.

When taken consistently as prescribed, oral PrEP has an efficacy of around 90% to 99% in preventing HIV infection.


Who needs PrEP therapy?


PrEP is recommended for sexually active adults who weigh over 35 kg and do NOT have HIV infection. It is important to remember that PrEP, especially Truvada, is prescribed to people who have clinically tested negative for HIV before starting the pill.

PrEp is recommended for people at high risk for acquiring HIV, including:

  • those partaking in condomless sex
  • those with an HIV-positive partner who is not on treatment
  • those with a partner whose HIV status is unknown
  • men who have sex with men
  • anyone with multiple sexual partners
  • transgender women
  • sex workers
  • drug-injecting users

Before starting PrEP

A healthcare provider will test for the following:

  • HIV
  • hepatitis B
  • serum creatinine
  • creatinine clearance
  • urine glucose
  • urine protein

Along with being HIV-negative, anyone considering PrEP needs to visit their healthcare provider to rule out hepatitis, especially hepatitis B, and impaired kidney functions. If you suspect you have been exposed to HIV recently, you need to inform your physician and monitor symptoms such as fever, chills, rash, night sweats, muscle aches, sore throat, fatigue, swollen lymph nodes, and mouth ulcers as they are often present during the acute infection stage.

Ongoing PrEP for HIV

The PrEP pill Truvada needs to be taken once a day orally with or without food. It is important to adhere to the daily prescribing schedule for full protection against HIV.

Once you start using PrEP, public health experts recommend certain tests to be done once every 3 months:

  • Testing for hepatitis B virus surface antigen (HBsAg) once, at or within one to three months of PrEP initiation
  • Hepatitis C virus antibody testing at or within one to three months of PrEP initiation and every 12 months after PrEP services are provided
  • Regular HIV testing, one month after PrEP initiation and every three months afterward
  • Regular testing for other STIs

PrEP side effects

Several studies have shown that Truvada is safe and effective for HIV PrEP. That being said, as with any medicine there may be a chance of developing some side effects such as:

  • Headache
  • Abdominal pain
  • Weight loss
  • Nausea

Safety information for oral PrEP

  • In those infected with HBV, severe acute exacerbation of hepatitis B has been observed in some people after discontinuing Truvada.
  • Kidney damage, including cases of acute renal failure and Fanconi syndrome, have also been reported with the use of TDF, a component of Truvada. Avoid high-dose or multiple NSAIDs while on the medication.
  • Anyone on Truvada who develops either hepatitis or is exposed to HIV needs to get in touch with their healthcare provider for dose adjustment. Do not stop taking the medicine on your own.
  • In case you miss a PrEP dose and it has been less than 12 hours, you can take that dose. If it has been more than 12 hours, wait until your next scheduled daily dose. Do not take more than one dose a day. Do not take two doses at the same time. Call your doctor if you are not sure what to do.

Finally, remember that Truvada is meant to be used for HIV PrEP to lower the risk of HIV infection as a part of an all-encompassing prevention plan that also includes other preventive measures, such as adherence to daily dosage and safer sex behaviors (condoms, knowledge of partner’s HIV status) to lower the risk of STIs. Oral PrEP such as Truvada will not protect you from other STIs such as chlamydia, gonorrhea, syphilis, herpes, etc.

If you’re unsure about how to access PrEP in Toronto, we’ve got you covered. Start by taking our free HIV risk-assessment PrEP quiz.

For those looking for convenient and discreet delivery of PrEP in Toronto, sign up with us to start your journey to safe sex and good health.



The opinions shared in this article belong to the author and, like all content on Gambit’s Health Hub, should not be considered a replacement for professional medical advice, diagnosis, or treatment. If you have any health-related inquiries, consult with your preferred healthcare professional or visit a licensed, Canadian physician through Get Gambit for a supported condition.

This article has been medically reviewed by:

Dr. Taneer Ahmed, MBBS, MS


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