On-demand PrEP is a PrEP dosing schedule that involves taking pills only on days before and after having sex, as opposed to taking PrEP daily. This provides another option for people interested in PrEP; however, this dosing schedule can be confusing compared to daily dosing, and it is not a suitable option for everyone. CATIE talked to two service providers experienced in discussing PrEP with service users to get their perspectives and insights related to on-demand PrEP use, what service users know about on-demand PrEP and how to talk to them about their PrEP options.
- Dr. Caley Shukalek is a clinical associate professor and physician in the Departments of Medicine and Community Health Sciences at the University of Calgary Cumming School of Medicine, with a clinical and academic focus on the treatment and prevention of HIV and other sexually transmitted infections (STIs) using both pharmaceutical and health system interventions. Caley is also the chief medical officer for PurposeMed, a technology-enabled health service company that operates HIV prevention and treatment services across much of Canada under its brand, Freddie.
- Joshua Cecil is the men’s outreach coordinator at the AIDS Committee of Ottawa (ACO).
See more in the article: What’s the 411 on PrEP 2-1-1? On-demand PrEP for preventing HIV
Dr. Caley Shukalek, clinical associate professor and physician at University of Calgary Cumming School of Medicine; chief medical officer at Freddie (PurposeMed)
What proportion of your patients who take pre-exposure prophylaxis (PrEP) choose to take it on-demand? What are the common reasons they choose it over daily PrEP?
In my individual practice, it is a very low proportion (less than 10%). Not every patient brings it up to me and I wait to talk about it as an option until I have a sense of their sexual behaviours to know if PrEP on-demand is clinically appropriate for them. I find there are multiple reasons why a patient might bring it up. The most common reason is simply curiosity because they have heard of it and might not have a clear understanding that it is the same medication used less often because they do not have sex frequently. Side effects and/or wanting to minimize exposure to the drug are the next most common reasons. An important, but less common, reason is a clear understanding that on-demand might be what works best for their individual sexual behaviours — meaning they have infrequent, predictable sexual interactions.
After a conversation with patients, I find most settle on daily PrEP, but I reinforce the importance of communicating with me if they are going to take it another way. Sometimes simply taking a break from daily PrEP is a better option for a patient if they know they won't be sexually active in any form for several weeks in a row — again something I ask patients to tell me about if they will do this or have done it.
Do your patients ever express confusion around how to take on-demand PrEP? How do you explain on-demand PrEP dosing to your patients?
I would say confusion around how to take on-demand PrEP exists among patients and prescribers. For patients, this is understandable because the instructions are nuanced and taking it reliably is key to it being effective. For prescribers, this probably has to do with overall comfort with PrEP and low frequency of prescribing it on-demand.
I have unfortunately seen new patients previously prescribed on-demand PrEP who have acquired HIV because they took it incorrectly. These instances have been from not understanding how to use on-demand PrEP properly (i.e., not taking the two doses early enough or not taking the whole course) or from incorrectly assessing their risk of HIV infection (i.e., not taking it with known or regular partners they assumed were HIV negative). These things can also happen with daily PrEP, but they are less likely because of the decreased complexity of using it properly.
After determining that on-demand PrEP is appropriate for a patient, I emphasize the following:
- It is important to have sufficient drug levels in their system to prevent an HIV infection. This goes for daily and on-demand use of PrEP.
- It needs to be taken for 100% of sexual encounters, including with regular and known partners.
- The actual dosing: Two tablets must be taken at least two hours before the first sexual encounter to ensure there is enough drug in their system when a potential HIV exposure happens. Since HIV stays in the system after the sexual encounter(s), a PrEP dose needs to be taken every 24 hours until TWO days after the last sexual exposure.
- Examples:
- If a person has sex on a Tuesday, they need to take two pills at least two hours before sex and then one pill a day on Wednesday and Thursday (total of four tablets).
- If a person has sex several times over a weekend, on a Friday, Saturday and Sunday, they need to take two pills at least two hours before sex on Friday and one pill a day on Saturday, Sunday, Monday and Tuesday (total of six tablets).
- Testing for HIV and other STIs still needs to be done every three months, or sooner if there are concerns.
- On-demand PrEP is for people with infrequent, predictable sexual exposures. If a person is using on-demand PrEP four or more separate times a month, they might as well take it daily because the total drug exposure is similar, without the complicated dosing.
I then ask the patient to repeat this back to me so I know they understood everything I just told them. As you can tell, this takes a fair amount of time for a provider to go through compared with "take a pill every day."
In your opinion, what could improve access to and understanding of on-demand PrEP for both prescribers and patients?
First and foremost, patients and providers need to understand that on-demand PrEP needs to be clinically and behaviourally appropriate. Not everyone is a candidate. Some people are just having a lot of sex, and good for them! And for some populations we don’t have any evidence to know that it will work.
From there, I think providers need access to clear and concise information to understand WHY they might prescribe it and clear guidance on how to talk to patients about it. Patients need reputable information about on-demand PrEP, who it might work for, and how to take it from providers who will have an honest discussion with them.
The most important thing for me is that patients have trust in me as a provider to inform them of their options, to talk honestly and to be flexible in terms of what would be clinically appropriate for them at a given point in time. Circumstances change, so the plan will probably change too.
Joshua Cecil, men’s outreach coordinator, AIDS Committee of Ottawa (ACO)
In your experience, how common is it for service users who are interested in PrEP to ask about or know about on-demand PrEP as a potential strategy?
I do outreach on Grindr (an app), and lots of folks ask me about PrEP. I connect them with the PrEP clinic we run at ACO twice a week. People do ask me about different ways of taking PrEP, but most people seem to prefer taking it daily. I would say it is a lot less common for people in my community to be interested in on-demand PrEP.
What questions do people in your community have about on-demand PrEP? What benefits or challenges do they identify, related to on-demand PrEP?
A common question people have is about the effectiveness of on-demand PrEP. Some are concerned about how much protection it provides if it’s not taken daily.
I have also heard from a few people that they prefer not to take pills every day, especially if they are not sexually active regularly.
One benefit people see in taking on-demand PrEP is that their pills can last longer – these are people with a daily PrEP prescription, but they take it on-demand to save pills. Unfortunately, affordability is the main challenge when it comes to accessing PrEP. It is quite expensive for those who don’t have health insurance.
Personally, if I did not have health insurance through my work, I don’t think I would be on PrEP. My health insurance covers 90% of my PrEP cost, and the rest is covered by the Trillium program.
How do you talk to service users about their options when it comes to daily vs. on-demand PrEP regimens?
I talk about both PrEP options with service users, and at the end of the day, it’s up to them to decide what way suits them best. Sometimes, even after I explain how to take PrEP on-demand, I hear that people find it confusing or are unsure that they will be able to take it correctly. I’ve had a couple guys tell me they’ve decided to take on-demand PrEP, but then when I see them again, they tell me they are worried they didn’t take it properly and won’t be protected from HIV.
I personally recommend that folks take PrEP daily as it gives 99% protection, but I feel less confident about the effectiveness of on-demand PrEP.
As a PrEP user, have you ever thought about taking in on-demand?
No, I have only ever wanted to take PrEP daily. For me, I don’t think it’s realistic to always plan sex in advance. Sometimes it just happens. I would worry about forgetting or missing a dose if I took it on-demand. So, I feel that daily PrEP gives me more confidence that I am protected from HIV. If I am taking a pill already, it’s easier for me to just take it every day.