Adherence & PrEP Regimens
PrEP Regimens
In most cases, PrEP is prescribed as a pill to be taken daily, once per day, seven days per week. A less common PrEP regimen (or way of taking PrEP) is known as ‘on-demand’ or ‘intermittent’ PrEP.
When taking PrEP this way, a person takes 2 pills 2-24 hours before sex and then takes one pill daily until 48 hours after their last sexual activity. This way of taking PrEP was tested among men who have sex with men and was demonstrated to reduce HIV risk by 86%.
It’s important to note that on-demand PrEP has not been proven effective for other populations and is not currently recommended for cisgender women, trans men, or anyone having receptive vaginal/frontal sex, due to the longer period of time required to achieve protective vaginal drug levels.
Ultimately, the decision about what PrEP regimen works best for someone should be determined through a conversation between them and their healthcare provider.
Why Does Adherence Matter?
The CDC states that PrEP reduces HIV risk by 99% when taken at least 4 times per week. If taken less often than 4 times per week, PrEP is less effective at preventing HIV, increasing the chance that someone taking PrEP could still be infected despite taking PrEP.
While the two HIV medications found in PrEP (TDF & FTC), when taken are prescribed, are effective enough on their own to prevent HIV infection, they are not effective enough on their own to treat HIV infection in someone who is HIV-positive. For people living with HIV, the medications in PrEP are often paired with a third medication so that they can effectively treat HIV. Therefore, if someone taking PrEP becomes HIV-positive without knowing it and continues to take PrEP, the medication will not be effective at treating the HIV in their body.
When this ineffective medication exists in the body alongside HIV, over a period of time the HIV virus can build up a resistance against it. In this case, HIV would no longer respond to the two types of HIV medication used in PrEP. As these medications are common components of many HIV treatment combinations, this means that the person would lose many of these treatment combinations as options, limiting their HIV treatment options in the future.
Adherence Tips
Some people experience greater challenges to adhering to PrEP. Some useful tips to make adherence easier are:
Taking medication at the same time every day (perhaps after main meals or together with other medications)
Downloading an app or setting a reminder on your phone (i.e. medisafe app, thesexyouwant.ca/reminder)
Storing the medication somewhere visible
If someone is using recreational drugs, making a plan as to when and how they will take their medication
For people without stable housing or who experience other factors which make medication storage challenging, they should speak with a community-based organization or their pharmacy about possible medication storage options.