Pre-exposure Prophylaxis- How effective is PrEP?

For anyone wanting to lower the chance of getting HIV, PrEP (pre-exposure prophylaxis) is a broadly effective method. This medication is an antiretroviral that lessens the risk of HIV during potential exposure when taken as prescribed. People generally tolerate PrEP medication well, making it a safe and effective prescription in Canada. It is currently only available in pill form as a once-daily medication.

What is Pre-exposure prophylaxis?

PrEP is an HIV preventative that uses antiretroviral drugs to lessen the likelihood of getting HIV when taken by HIV-negative people. This medication is a prescription medication (meaning a qualified professional will have to write the script for users) and functions as two antiretroviral drugs within one pill. These drugs are some of the same treatment for those living with HIV but are not the same prescription dose.

PrEP medications work by building high level of antiretroviral drug concentrations within the body. These concentrations will collect within genital regions, acting as a barrier to HIV transmission (especially in areas of thin membranes or mucous membranes). These areas are susceptible to microtears during intercourse, giving HIV easier access into the body. Should HIV enter the body, PrEP prevents it from reproducing within a new host cell. This medication works regardless of sexual orientation.

How is PrEP taken?

There are prescriptions available as a daily medication and an on-demand cycle for male-to-male exposure. Essentially, gay, bisexual, or other men who have sex with men can opt to take this medication on-demand. Other people wanting protection against HIV can take this medication daily.

Individuals must take medications as needed for on-demand schedules. This schedule includes before and after having sex, instead of on a daily routine. As a daily medication, users will take a pill twice daily by mouth. Taking this medication as directed ensures high concentrations of the drug within the body. The majority prefer the daily scheduling of the medicines for consistent protection against HIV. Individuals can take this medication on short-term intervals, with the ability to stop and start the medication as needed.

How long does it take the medication to become effective?

Large quantities of evidence support that daily PrEP effectively reduces the transmission rate of HIV if used correctly and consistently. For male-to-male interactions, medications need seven days to become an effective barrier. For other uses, PrEP requires 21-days of consistent use to build up barrier concentrations within the body. There is limited evidence to support that PrEP can also reduce the risk of HIV transmission among individuals who inject drugs.

PrEP medication is a piece in a prevention package. Users should always participate in ongoing medical appointments, testing, and treatment for STIs and stick with adherence schedules. Adherence to routine is paramount to reducing the risk of HIV. The higher the level of compliance with participants, the lesser the chance of transmission.

How Well Does PrEP Protect Against HIV?

When taken consistently, PrEP medications have a nearly 100% prevention rate for sexual HIV transmission. The PrEP HIV connection has been vastly studied, proving the efficiency of protection. For all prescription users (thousands globally), only a tiny handful of HIV-positive statuses have come up. Studies have shown that PrEP is highly effective for anal and vaginal sex (if used correctly), but adherence is crucial for ongoing success. Some evidence suggests the drug needs more extended time frames to reach optimal levels within vaginal tissues than rectal tissue. As such, daily dosing of PrEP is likely more important for transgender men and CIS women. When relating to drug use, the risk reduction was 49%.

Who Can Take PrEP Medications?

Anyone who is currently HIV negative and at high risk of infection should consider this medication. According to Canadian guidelines, men who have condomless sex and have tested positive for a rectal STI in the last year tested positive for infectious syphilis, have used post-exposure prophylaxis more than once, or maintain a high score on a valid HIV risk assessment tool are qualified candidates. Likewise, anyone who has condomless sex with a partner that is HIV positive (and not virally suppressed) or shares injection drug equipment should also consider this medication.

Other criteria for PrEP might include individuals who engage in risky sexual activity with unknown status partners or other patient-reported risk behaviors. Always talk to your health care provider about whether this medication is of benefit to your overall health.