Unlike the prescribing of HIV medication for the treatment of people living with HIV, there are no special restrictions on the prescribing of TDF/FTC for use as PrEP.
Instead, PrEP can be prescribed by various healthcare providers such as an HIV or Infectious Disease Specialist, a Family Doctor or General Practitioner, a Nurse Practitioner, or Pharmacists with additional prescribing authorization. Although not all healthcare providers are knowledgeable about PrEP, the guidance laid out on this website and in the linked resources should provide all the information you need to know to feel comfortable prescribing PrEP for someone who is eligible based on current guidelines.
PrEP Eligibility Criteria
Given that different Canadian populations and subgroups experience varying levels of HIV vulnerability, the eligibility criteria may differ depending on which communities or populations an individual identifies with. To provide an example of this, here are the eligibility criteria for gay, bisexual, and other men who have sex with men (MSM) and transgender women (TGW):
PrEP is recommended for MSM and TGW who report condomless anal sex within the last 6 months and who have any of the following:
- Infectious syphilis or rectal bacterial STI, particularly if diagnosed in the preceding 12 months
- Recurrent use of nPEP (more than once)
- Ongoing sexual relationship with HIV positive partner with substantial risk* of transmissible HIV
- High-incidence risk index (HIRI-MSM) risk score ≥11
PrEP is not recommended in the context of a stable closed relationship with a single partner with no or negligible risk of having transmissible HIV.
The decision as to whether or not someone is eligible for, would benefit from, or should start PrEP should be made within the context of a comprehensive sexual health discussion between an individual and a healthcare provider they trust. Additionally, the various factors determining someone’s eligibility for PrEP might change over time, meaning that someone who would benefit from PrEP today might not benefit from it a year from now. Because of this, it is important that in addition to ongoing screening and monitoring (as laid out in the next section), patients and providers continue to have regular discussions about a person’s sexual health and whether or not PrEP remains the best HIV prevention option for them
Establishing HIV Status
If it is determined that an individual is eligible for PrEP, the next step is to determine their current HIV status. To establish an individual’s current HIV status, the Canadian PrEP/nPEP Guidelines recommend the following process.
Evaluate the individual for signs or symptoms related to acute HIV infection within the last twelve weeks.
If acute HIV infection is not expected, an individual’s baseline HIV status should be determined using a laboratory-based 4th generation assay when available. If acute HIV infection is suspected, additional laboratory evaluation with an HIV RNA test should be ordered. Healthcare providers can contact the virologist on call or an HIV/ID specialist to have HIV RNA testing approved. During this time, PrEP initiation should be delayed.
The importance of establishing an accurate HIV-negative status before initiating PrEP cannot be overstated. If someone starts PrEP who is already HIV-positive, it can result in issues of medication resistance. The reasons for this are:
- PrEP (TDF/FTC) only contains two different HIV medications (tenofovir disoproxil fumarate and emtricitabine). These two medications taken together as PrEP are sufficient to prevent new HIV infection. However, the successful treatment of HIV in someone who is already HIV-positive requires three or more different types of HIV medication (often combined in one single pill). Therefore, PrEP (TDF/FTC) on its own is not sufficient to treat HIV infection.
- Because of this, if someone who is HIV-positive begins PrEP, the HIV will not respond effectively to the treatment and can build resistance against the medications in PrEP. If the HIV in someone’s system becomes resistance to these two medications, then these medications – which are quite common in many combination HIV treatment regimens – will no longer be effective treatment options for them. Although there are treatment options which do not contain TDF or FTC, it is not desirable to lose two common HIV medication options for treatment before someone is even diagnosed.
Finally, if it is determined that your patient’s HIV status is negative and you choose to provide them with a PrEP prescription, it is important to counsel them to use other HIV prevention options, such as condoms, until they have taken PrEP for at least seven days for anal sex or twenty days for vaginal or frontal sex. This is to ensure that there is enough PrEP in their system to provide adequate protection against HIV infection. If your patient is taking PrEP on an intermittent or “on-demand” basis instead of daily, refer to the Canadian PrEP/nPEP guidelines to learn more.