PrEP 101

What is PrEP?

Pre-Exposure Prophylaxis (PrEP) is a preventive treatment that reduces the risk of contracting HIV by up to 99% when taken correctly. It consists of taking an antiretroviral medication before a potential exposure to the virus, thereby preventing HIV from infecting the body's cells.

Is PrEP for me?

PrEP is a recommended treatment for:

Men who have sex with men, trans and non-binary people

  • If you do not always use a condom
  • If you have partners whose HIV status is unknown or who have a detectable viral load
  • If you have recently had an STI (syphilis, gonorrhea, chlamydia)
  • If you participate in chemsex contexts

And other people likely to be at high risk

  • If you have multiple or anonymous sexual partners without consistent condom use
  • If you share drug injection equipment
  • If you have unprotected sex with an HIV-positive person who is not on treatment or with people from groups where HIV prevalence is high
  • If you have used PEP (Post-Exposure Prophylaxis) more than once
  • If you are a sex worker

During a consultation, your pharmacist will explain the options and recommendations to help you choose a treatment adapted to your situation. There are two oral intake schedules and one injectable option.

Oral PrEP

How to take oral PrEP?

Oral PrEP: daily use vs. on-demand use

Method How to use Effectiveness Why choose this option
Daily Use 1 pill per day, at the same time. Over 99% protection when taken correctly. Ideal for frequent or unpredictable sex. Maintains a stable blood concentration, offering a small margin of error if a dose is occasionally missed.
On-Demand (2-1-1) Two pills 2-24h before sex, one pill 24h after the first dose, then a final pill 24h after the second dose (2-1-1 schedule). If sex continues over several days, continue one pill per day. After the last encounter, continue PrEP for 2 days before stopping. Very effective, provided the schedule is strictly followed. Suited for occasional relations. Only recommended with Truvada® and its generics. Indicated for anal sex only. Requires strict planning.

Oral PrEP: approved medications

Medication Indications Advantages Precautions
Truvada® & generics
(Tenofovir disoproxil + emtricitabine)
Daily **and** on-demand use Often the first option covered by insurance plans. Suited for all types of exposure (anal and vaginal). Can slightly affect kidney function and bone density, which is monitored.
Descovy®
(Tenofovir alafenamide + emtricitabine)
Daily use only (for cis men and trans women) Reduced impact on bone and kidney health. Not validated for protection during vaginal sex. Not for on-demand use.

Injectable PrEP

Long-lasting protection at all times, without pills

The only medication currently approved in Canada is Long-Acting Cabotegravir (Apretude®). Other medications are in development.

Injectable PrEP is an alternative to oral PrEP. Clinical studies have shown it can offer superior protection, notably due to better treatment adherence. It is approved for people of all genders.

Administration method

Step Description
Oral phase (optional) Take 1 pill per day for 30 days. This phase is optional and not recommended in most cases.
Initial phase Receive 1 injection once a month for 2 consecutive months. This phase effectively starts the treatment.
Maintenance phase Receive 1 injection every 2 months to maintain protection against HIV. This rhythm allows for simple and discreet management.

Injections can be given up to 7 days before or after the scheduled date, offering a 14-day window. If you must be away beyond this period, let us know: a temporary pill treatment will be prescribed to maintain your protection.

Advantages of injectable PrEP

  • Demonstrated superior effectiveness to oral PrEP in clinical studies
  • Continuous protection without the need for daily intake
  • Eliminates risks related to missed pills
  • Does not require strict planning around sexual activity
  • Ideal alternative for those who struggle with a daily routine or have side effects with oral PrEP

To consider before choosing injectable PrEP

  • Persistence of the drug after stopping: Residual concentrations of cabotegravir can remain in the blood for up to a year. An HIV infection during this period could make the virus resistant to certain treatments. Alternative protection is essential after stopping.
  • Adherence to the schedule: Injections must be received on time. A delay can reduce protection.

What tests are required to start PrEP?

Before starting PrEP, tests are required to ensure your safety:

  • HIV test: To confirm you are HIV-negative.
  • Hepatitis B immunity test: To ensure you are immunized. If the result is negative, the vaccine will be offered free of charge for those with a RAMQ card or private insurance.
  • Kidney function test: For those opting for oral PrEP, kidney health is monitored periodically.
  • Regular medical follow-up: HIV and STI tests are then recommended every 3 months.

Other tests may be suggested depending on your situation to ensure your safety. Our pharmacists will support you throughout your journey, with personalized reminders and advice adapted to your reality.

What are the side effects?

Oral PrEP

Only 1% to 10% of people on PrEP experience side effects, which generally disappear after one to two weeks. The most common are nausea, headaches, vomiting, and diarrhea.

In the long term, a slight decrease in bone density or kidney function may occur in a small number of people. These rare effects are reversible upon stopping the treatment. Fear of side effects should not prevent you from trying PrEP.

The newest oral PrEP option, tenofovir alafenamide + emtricitabine (Descovy®), avoids the risks of negative effects on kidney function and bone density. Additionally, people who choose this medication report about half as many side effects compared to tenofovir disoproxil + emtricitabine (Truvada®) and its generics.

Injectable PrEP

Temporary reactions at the injection site, such as pain, tenderness, nodules, or induration, occur in the majority of patients. More rarely, temporary fatigue or headaches may also appear. These effects are generally mild to moderate and well-tolerated by the vast majority of users.

Optimizing protection against other STIs and pregnancy

PrEP only protects against HIV, not against other STIs or pregnancy. It is therefore crucial to continue getting screened regularly and to use condoms and/or a contraceptive.

Other prevention strategies

PrEP should be part of a global STI prevention strategy. For optimal protection, it is strongly recommended to use other protection methods in addition to PrEP.

  • Regular screening: Consult your healthcare professional for STI and HIV screening at the recommended frequency.
  • Condoms: Using condoms, in addition to PrEP, maximizes your protection against HIV, STIs, and pregnancy.
  • Vaccination: Ensure your vaccinations against hepatitis A and B are up to date. Also, discuss vaccination against HPV and monkeypox with your healthcare professional.
  • Doxy-PEP: If you are at risk, Doxy-PEP can significantly reduce the risk of bacterial STIs.
  • Knowing your partners' status.

Consult us to discover the protection options adapted to your reality.

More Questions?

Both methods effectively protect you from HIV, but they have distinct profiles regarding protocol, efficacy, and side effects.

The choice between them depends on your lifestyle and what you prioritize.


Rhythm and administration

  • Oral PrEP: Requires daily discipline (or rigorous planning for the "on-demand" schedule). It is self-administered.
  • Injectable PrEP: Consists of an in-clinic appointment every two months for an injection administered by a healthcare professional.
    • Our service to make your life easier: To offer you maximum flexibility, we can administer the injection in our private room at the pharmacy, coordinate the delivery of your medication to another clinic, or discuss remote or at-home service options with you.

Clinical effectiveness

  • Clinical studies have demonstrated that injectable PrEP offers superior protection against HIV compared to oral PrEP. Furthermore, one of the major advantages of the injection is that it eliminates the risk of missed doses, a critical factor for ensuring the effectiveness of oral PrEP.
  • When taken rigorously as prescribed, oral PrEP offers protection that exceeds 99% against HIV transmission.

Tolerance profile and common side effects

  • Oral PrEP: Very well-tolerated. Mild start-up effects (nausea, headaches) are possible. Kidney function is monitored as a precaution.
  • Injectable PrEP: Bypasses the digestive system but frequently causes normal and temporary reactions at the injection site (pain, tenderness).

Time to effectiveness

  • Oral PrEP: Effective after 7 days (for anal sex) or 21 days (for vaginal sex). (2 hours for on-demand oral PrEP)
  • Injectable PrEP: Effective 7 days after the first injection for all types of sex.

Comparative summary: Pros and Cons

Oral PrEP (Pills)

  • Pros: Flexibility (allows for "on-demand" use), autonomy, simple and quick to stop.
  • Cons: The mental load of a daily pill, risk of missed doses compromising protection.

Injectable PrEP

  • Pros: Peace of mind (no daily management), demonstrated superior efficacy, discretion.
  • Cons: Appointment commitment, injection site reactions, complex discontinuation process that must be planned.

The choice is yours: the flexibility of the pill or the peace of mind of the injection.

The right response depends on your dosing schedule. Here is a guide for each situation.


If you take daily PrEP (1 pill per day)

  • A single, occasional missed dose:

    • Take the missed pill as soon as you remember, then resume your normal schedule. Never double the dose.
    • While a single missed dose only slightly reduces protection if you've been taking PrEP for more than 7 days, consistency is key to its effectiveness. If condomless penetrative sex occurred during this period, please contact us. We will take the time to analyze the situation with you to provide safe, personalized advice.
  • Several consecutive missed doses:

    • Consider your protection to be reduced. Use additional protection (a condom) for the next 7 days of daily intake to re-establish full protection. If condomless penetrative sex occurred during this period, please contact us. We will take the time to analyze the situation with you to provide safe, personalized advice.

If you take on-demand PrEP (2-1-1 schedule)

This schedule requires strict adherence. Any deviation can compromise your protection.

  • Forgetting the 2 pills BEFORE sex: You were not protected by PrEP.
  • Forgetting a pill AFTER sex: The effectiveness of PrEP could be reduced.

What to do in case of a significant mistake?

If you think your protection was compromised and you had a risky sexual encounter, contact us immediately. We can assess the situation with you and discuss the relevance of PEP (post-exposure prophylaxis), an emergency treatment.

Tips to avoid missed doses

  • Set a phone alarm or use a pill organizer.
  • If you frequently miss doses, talk to us. Injectable PrEP might be a better option for you.

No, absolutely not. This is one of the most persistent misconceptions about PrEP.

Historically, the first studies and promotional campaigns heavily targeted gay men, bisexual men, and other men who have sex with men (MSM), as they represented (and still represent) one of the populations most affected by the HIV epidemic. This is why the association is so strong in people's minds. But the reality is much broader.


The only real criterion: risk, not gender or orientation

PrEP is for ANYONE who is HIV-negative and at substantial risk of acquiring HIV, regardless of their gender, sexual orientation, origin, or lifestyle. The virus does not discriminate, and neither does prevention.

Risk can apply to many people, including:

  • Women (cisgender and transgender) and non-binary people, especially if they have partners whose HIV status is unknown.
  • People who inject drugs (PWID) and who might share equipment.
  • Sex workers.
  • People with multiple partners or partners who themselves have multiple partners.

Equitable access: our commitment

We recognize that for many people, accessing preventive healthcare like PrEP can be fraught with obstacles. Stigma, language or cultural barriers, a legitimate mistrust of the healthcare system, or simply a lack of targeted information are realities.

This is particularly true for certain communities, including Indigenous communities, Black communities, racialized people, and migrants, who face systemic health inequalities and therefore sometimes increased risks.

Our role, as front-line healthcare professionals, is to work to break down these barriers. We are committed to offering a safe, confidential, and non-judgmental space where every person, whatever their reality, can discuss their sexual health and access PrEP if it is the right option for them.

To see Doxy-PEP as a simple "add-on" to PrEP is to only see part of the picture.

In reality, their combination represents a much more complete and proactive approach to sexual health, with a dual impact: for you, and for the community.


A dual mission: protecting yourself and protecting others

  • For you: Using Doxy-PEP in addition to PrEP means regaining control and significantly reducing the burden of bacterial STIs, which can be a source of stress, repeated treatments, and discomfort.
  • For the community: It is also a public health gesture. By treating potential infections at the source, you help reduce the total number of active infections in the population and curb the rise in STI rates.

PrEP: the foundation of HIV prevention

It is essential to understand that Doxy-PEP never replaces PrEP. If your sexual practices warrant the use of Doxy-PEP, it means a risk of HIV exposure exists. For an HIV-negative person, PrEP must therefore absolutely be part of the overall prevention strategy.

Who is this combined approach for?

A health strategy must be based on solid scientific evidence. Currently, the clinical studies that have demonstrated the greatest benefits of Doxy-PEP have done so within a specific group.

This approach is therefore discussed on a case-by-case basis and is primarily intended for gay men, bisexual men, and other men who have sex with men (MSM). It is in this group that studies have proven that Doxy-PEP can very significantly reduce recurring bacterial infections.

This includes MSM who are:

  • Either PrEP users to prevent HIV.
  • Or people living with HIV (PLWHIV) on effective treatment (undetectable viral load, U=U).

Modern sexual health relies on combined prevention.

The idea is that there is no single magic bullet, but rather a set of tools that you can combine to create the strategy that perfectly fits your life and your needs. Here are the main tools at your disposal:


The Condom: the "all-in-one" protection

The condom (male or female) remains the only tool that protects against HIV, most other STIs, and unwanted pregnancies all at once.

PrEP: the continuous prevention of HIV

Pre-Exposure Prophylaxis (PrEP) involves taking a medication continuously to prevent HIV from establishing itself in the body. It is an extremely effective method for HIV-negative people.

Doxy-PEP: the post-intercourse prevention of bacterial STIs

Doxycycline Post-Exposure Prophylaxis (Doxy-PEP) involves taking an antibiotic after a risky sexual encounter to reduce the chances of contracting syphilis and chlamydia. It has no effect on HIV.

PEP (or PPE): the emergency prevention of HIV

Post-Exposure Prophylaxis (PEP) is a 28-day course of antiretroviral treatment to be started as soon as possible after a high-risk situation. It is an emergency solution for people who are not on PrEP.

TasP / U=U: treatment as prevention

This is the principle that a person living with HIV who is on effective treatment and has an Undetectable viral load cannot transmit the virus (U=U, or I=I in French). It is a major HIV prevention strategy.

Vaccination: the long-term prevention

Vaccination protects you long-term against several infections. Consider checking if you are up to date for Mpox (monkeypox), hepatitis A and B, and HPV (Gardasil®9).

Regular screening and communication

Getting tested regularly (every 3 months) and communicating openly with your partners are the foundation of a healthy sex life.


In summary, the best strategy is the one you build by choosing the tools that adapt to your life.

When taken correctly, PrEP is extremely effective, reducing the risk of contracting HIV by over 99%. The effectiveness of oral PrEP is directly linked to your adherence. It is a reliable and essential prevention tool.


The key: taking the treatment as prescribed

Studies show that protection is at its maximum (over 99%) for people who take their treatment rigorously (every day or according to the recommended schedule). Poor adherence, such as frequently missed doses, significantly reduces this effectiveness.

A new option: injectable PrEP

Injectable PrEP is a new option that provides constant protection without having to think about taking pills. An injection every two months protects you at all times.

PrEP: one tool in a global health strategy

While highly effective against HIV, PrEP should be part of a comprehensive prevention approach that includes:

  • Regular screening for other STIs.
  • Prioritizing Condom use depending on the context.
  • Vaccination (hepatitis B, HPV).
  • The knowledge of your partner's status, including that U=U (Undetectable = Untransmittable): a person living with HIV on effective treatment does not transmit the virus.

Protection is not always instantaneous; the time it takes to become effective depends on the type of PrEP you are using.

Each method has its own protocol for achieving maximum protection.


Daily Oral PrEP

This is the most studied method. The delay varies depending on the type of sexual intercourse:

  • For anal sex: Protection is optimal after 7 days of continuous daily use.
  • For vaginal sex: Protection is optimal after 21 days of continuous daily use.

On-Demand Oral PrEP (2-1-1)

This method provides very rapid protection for anal sex only.

  • Protection: Effective as soon as 2 hours after the initial double dose (2 pills), as long as the full protocol (2-1-1) is followed correctly.

Injectable PrEP

This method provides continuous protection for all types of sexual intercourse.

  • Protection: Protection is considered optimal 7 days after the first injection.

It is essential to respect these timelines and to use additional protection (like a condom) until maximum protection is achieved.

The decision to stop PrEP should always be discussed with a healthcare professional. This ensures you stop safely and allows you to plan the next steps. You cannot simply stop the treatment the day after a risky sexual encounter.


Stopping Oral PrEP (pills)

To be protected from an exposure that might have occurred during your last sexual encounter, you must continue taking the pills for a certain period afterward (this is often called the "tail").

  • After anal sex:

    • If you are on daily PrEP, it is recommended to continue it for 2 to 7 days after the last potential exposure. Your pharmacist will tell you the exact duration for you.
    • If you are on on-demand PrEP (2-1-1), the protocol already includes the post-intercourse doses. Just make sure you complete it correctly.
  • After vaginal sex:

    • It is recommended to continue PrEP for 7 days after the last potential exposure.

Stopping Injectable PrEP

Stopping injectable PrEP is more complex because the medication stays in your body at a slowly decreasing concentration for several months.

  • Risk of resistance: During this period, if you are exposed to HIV, the virus could develop resistance to the medication.
  • Mandatory prevention: For this reason, it is crucial to use another prevention method (like oral PrEP or condoms) for up to a year after your last injection.

Restarting PrEP is always an option

Life changes, and so do your prevention needs. If you want to restart PrEP after a break, it's simple: you just need to complete a new round of screening tests and consult a professional. Never resume taking old pills without new medical advice.

Yes, injectable PrEP is an extremely effective option and is increasingly accessible in Quebec. Here are the details to answer these two excellent questions.


A superior effectiveness

Yes, clinical studies demonstrate that injectable PrEP offers superior protection against HIV compared to oral PrEP.

One of the clear advantages of the bimonthly injection is that it completely eliminates the risk of missing a daily pill. Since consistent adherence is the most important factor for ensuring the effectiveness of oral PrEP, the injectable method provides continuous and stable protection. It can therefore be considered one of the most reliable HIV prevention methods available today.

Who can get it and is it covered in Quebec?

Injectable PrEP, like oral PrEP, is intended for people who are at substantial risk of contracting HIV and who have a negative screening test.

Regarding coverage, injectable PrEP is covered by RAMQ (the public plan) and all private insurance plans in Quebec. As with oral PrEP, the final cost to you depends on your specific coverage, and financial support programs from the manufacturer are available to help reduce or completely eliminate this cost. This is why many people say they receive PrEP "for free."

Is it the right option for you?

Despite its effectiveness, injectable PrEP is not automatically suitable for everyone. It is a very personal choice. Here are a few points to consider:

  • The appointment schedule: Are you comfortable with the idea of a clinic or pharmacy appointment every two months to receive your injection?
  • Fear of needles: Although the injection is quick, it is still an intramuscular injection. This is an important factor for some people.
  • Your lifestyle: If you travel very frequently or for long periods, the logistics of a fixed appointment can be more complex than carrying pills with you.
  • The nature of the treatment: The medication stays in the body for a long time. This means that a side effect (like tenderness at the injection site) can also last longer than if one were to simply stop taking a pill.

In summary, injectable PrEP is a major advancement that simplifies life for many people. A frank discussion with one of our pharmacists is the best way to weigh the pros and cons and to determine if this option fits your reality.

The answer is simple: by following your treatment rigorously.

The effectiveness of PrEP is not a matter of luck, but of science. Maintaining a sufficient concentration of the medication in your body is the only way to achieve the greater than 99% effectiveness demonstrated in studies.


What does that mean in practice?

It means following the protocol that was prescribed for you, without compromise.

  • For daily oral PrEP: Take one pill, every day, ideally at the same time. Integrate it into a routine (waking up, meals, bedtime) to make it automatic. Maximum protection is reached 7 days after starting daily PrEP.
  • For on-demand oral PrEP: Strict adherence to the 2-1-1 schedule is non-negotiable. Each dose plays a specific role in ensuring your protection.
  • For injectable PrEP: Maximum protection is reached 7 days after the first injection. You must then attend all your appointments (every 2 months) to maintain it.

What to do if you have trouble with adherence?

Maintaining a perfect routine can be challenging. If you frequently forget to take your medication, the important thing is to talk about it.

  • Discuss it with us: Your pharmacist is your ally. We can find practical solutions with you, such as reminder apps or pill organizers.
  • Consider an alternative: If missed doses are frequent, injectable PrEP might be a better option for you, as it completely eliminates this risk.

Your regular follow-up appointments are the ideal time to discuss your adherence to the treatment and adjust the strategy as needed. This is an essential dialogue for your safety.

Consultation gratuite

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