Ask Your Pharmacist

January 16, 2020

I’ve been hearing a lot about pre-exposure prophylaxis (PrEP) being used to prevent getting HIV. What can you tell me about this?


This is fantastic question that I am happy to discuss with you. For the first time in human history, there is a foreseeable end to the HIV pandemic!

What is PrEP?

Pre-exposure prophylaxis (PrEP) is a way for an HIV negative person who is at risk of HIV infection to reduce their risk of getting HIV by taking daily medication. It involves taking a prescription pill that contains two medications. You must take the pill every day for it to work. The formulation of PrEP approved by Health Canada is known as Truvada. Truvada is a single tablet that contains two antiviral medications known as emtricitabine 300mg and tenofovir disproxil fumarate 200mg. The pill is taken once daily, with or without food. It is crucial not to skip doses.

How does PrEP work?

PrEP interferes with the pathways that HIV uses to cause a permanent infection. When oral PrEP is taken consistently and correctly, antiretroviral drugs get into the bloodstream and genital and rectal tissues. The drugs work to help prevent HIV from replicating within the body’s immune cells, which helps to prevent a permanent infection.

How effective is PrEP?

Based on all the available evidence, it is now widely accepted that the risk of getting HIV through sex is reduced by up to 99% when taking PrEP every day.

Who might consider taking PrEP?

PrEP is for people who are at risk for HIV. You might want to use PrEP as a way of staying HIV negative if you sometimes have vaginal or anal sex without using a condom and you don’t know the current HIV status of one or more of your sex partners. PrEP is an option if you have a sex partner who is HIV positive and not on successful treatment or if you sometimes use injection drugs and share needles.

How do I get PrEP?

PrEP must be prescribed by a physician or nurse practitioner. Alternatively, if you are not comfortable speaking with your primary care provider about PrEP or if he/she is not familiar with this drug therapy, you can obtain a prescription by contacting your nearest New Brunswick Sexual Health clinic:

Does PrEP protect against other sexually transmitted infections (STIs)?

PrEP helps to prevent HIV only and does not offer protection against STIs (such as herpes, chlamydia, gonorrhea or syphilis) or blood-borne infections such as hepatitis C. Other prevention strategies (such as using condoms or new injection equipment) are needed to reduce the risk of all other infections that can be passed through sex or sharing of injection drug use equipment.

How much does PrEP cost?

A one-month supply of the generic emtricitabine/tenofovir 300/200mg daily costs approximately $250.00. PrEP is generally covered for those people insured under the New Brunswick Prescription Drug Program and is also covered by many private insurers. Contact your insurance or your pharmacist to see if you have coverage for PrEP.

What are the side effects and monitoring?

PrEP is generally safe and well tolerated. Most adverse effects are mild and may include dizziness, diarrhea, nausea, headache, vomiting, rash, and intestinal gas. Skin discoloration may also occur. Being on PrEP involves more than just taking pills. Taking PrEP also involves seeing a doctor or nurse practitioner every three months for HIV testing, screening for other sexually transmitted infections (STIs), monitoring for possible side effects, and ongoing support.

What does undetectable = untransmittable (U=U) mean?

Undetectable = untransmittable’ is a campaign by the United Nations explaining how the sexual transmission of HIV can be stopped. When a person is living with HIV and is on effective treatment, it lowers the level of HIV (the viral load) in the blood. When the levels are low, it is referred to as an undetectable viral load. At this stage, HIV cannot be passed on sexually. 

PrEP is one highly effective HIV prevention for people who are HIV negative to prevent new infections. For more information about PrEP, visit:

Dr. Kevin Duplisea (PharmD BSc. Pharm, BSc. ACPR) is a pharmacist at Sharp’s Corner Drugstore in Sussex, New Brunswick. His opinions expressed in this newspaper are published for educational and informational purposes only, and are not intended as a diagnosis, treatment or as a substitute for professional medical advice, diagnosis or treatment. Send your questions to