You might have heard about PrEP, or pre-exposure prophylaxis, from a partner or in an advertisement. Approved in 2012 as a protective measure against HIV infections, PrEP is an enticing concept. But is PrEP really the magic bullet it is reported to be in protecting against HIV?Let’s dive into some details so you have a better idea of what to expect if you plan to use pre-exposure prophylaxis.
Pre-Exposure Prophylaxis (PrEP) – An Introduction
Pre-exposure prophylaxis (PrEP) is a type of medication that was created and approved with the purpose of helping to reduce the risk of getting the human immunodeficiency virus, or HIV. The idea behind PrEP medication is that an individual can significantly reduce the risk of contracting HIV when inadvertently exposed to an HIV-positive person.
How PrEP Works
As the name indicates, pre-exposure prophylaxis relies on a medical concept known as prophylaxis. Prophylaxis is a process in which one takes a medication before being exposed to an infectious agent like a virus to prevent illness from that virus in the event that one is exposed inadvertently. Contrary to what some people believe, PrEP for HIV works differently than the routine vaccines that many people receive during childhood or when going on a trip to a foreign country.
PrEP is similar to taking medications to protect against malaria when one is going on a trip to a foreign country. The idea behind PrEP for HIV is that you take the medication regularly and, by doing so, have enough of the protective medication in your body to saturate at-risk parts of your body such as your blood or genital areas. Later, if an exposure to HIV does occur, the hope is that the medication present in the exposed area will stop HIV from infecting the cells of the body and replicating.
So I have to take a medication for PrEP. What types of PrEP prescriptions are available? Pre-exposure prophylaxis for HIV currently consists of two different medications – emtricitabine and tenofovir. Emtricitabine, also known as FTC and marketed under the brand name, Emtriva, is known medically as being part of a class of medications known as nucleoside reverse transcriptase inhibitors. Other than its use in PrEP, emtricitabine has been used to treat and prevent HIV and hepatitis B. The other medication, tenofovir, also known as tenofovir disoproxil, is often known by its brand name Viread. In addition to its use in PrEP for HIV, tenofovir is also used to treat long-term hepatitis B infections. By itself, tenofovir has been found to decrease the risk of HIV in higher-risk patients.1
The combination of the two medications emtricitabine and tenofovir disoproxil form the foundation of PrEP medication. This combination of medications was approved by the Food & Drug Administration in 2004 and their use as a PrEP medication was approved in 2012.2 PrEP medication is available as a single pill and is packaged under the brand name Truvada.
These two medications were specifically selected for PrEP for HIV because they have some desirable characteristics. First, they have a longer half-life, meaning that they stay in the body for a longer period of time. Also, while some drugs have difficulty getting into the tissues of the body, emtricitabine and tenofovir disoproxil can get into at-risk body parts around the genitals. Finally, side effects of Truvada are mild overall although it can cause fatigue, difficulty sleeping, stomach cramps, liver swelling and headaches.
As of today, there is little HIV resistance to PrEP medications. When present, HIV resistance is primarily to the medication emtricitabine. There is a strain of HIV that resistant to tenofovir but, fortunately, no cases of drug resistance leading to failed PrEP have been identified.
How Effective Is PrEP?
PrEP is thought to reduce the risk of getting a permanent HIV infection after an exposure by as much as 90% in specific groups of high-risk people3. The risk reduction effect is believed to be related to the idea that PrEP works as a medication prophylaxis in possible areas of exposure in the body with.
Who Should Take PrEP?
The CDC recommends PrEP for people who are at a high risk for HIV from sex or injection drug use. Situations in which PrEP is recommended include, but are not limited to, the following:
- HIV-negative people with an HIV-positive partner
- Heterosexual people who have sex without condoms with partners who have an unknown HIV status and are high-risk (e.g. injection drug users)
- Gay or bisexual men who have been diagnosed with an STD in the past 6 months
- Gay or bisexual men who have had anal sex without a condom in the past 6 months
- People who have injected drugs in the past 6 months and have shared needles
As our recent review of STD statistics highlighted, other people might also consider taking even if they are not in a high-risk group given the alarming changes in STD statistics nationwide.
Some people wonder how long you have to be on PrEP for it to be effective. To be on the safe side, most recommendations say that PrEP needs to be taken for at least three weeks to be most effective. Four doses is said to be the minimum amount required to have some protection.
PrEP & STDs – Vigilance Required
It is important to understand that while PrEP can reduce the risk of contracting a permanent HIV infection when used regularly, PrEP is not foolproof. Even if one is fully compliant with the PrEP medication regimen for HIV, one can still contract HIV after an exposure. There are a multitude of reasons that this might occur – from the medication not being present in adequate levels to unique characteristics of a person’s specific body. And, once you get an HIV infection, it is not going away.
With this understanding, if you do plan on using PrEP, getting tested for HIV regularly is a must. Knowing your HIV status through a regular HIV blood test will not only keep you updated on your own health but will also protect any partners who might be at risk. And, even with regular testing and dedicated use of PrEP, avoiding exposures to HIV whenever possible and using protective measures like a condom is always a good idea. Fortunately, one study has shown that, for the most part, high-risk individuals are adding PrEP as another way to reduce the risk of HIV instead of as a replacement for other practices like using a condom.4
Also, even with PrEP medication protecting you against HIV, be mindful that pre-exposure prophylaxis will not protect you against other types of sexually transmitted infections such as chlamydia, gonorrhea and herpes. For people participating in higher-risk activities, regular testing with a more detailed STD lab test panel may be an even better idea than just HIV testing.
PrEP Costs – A Barrier To Use
While PrEP is an effective way to reduce the risk of getting a permanent HIV infection in high-risk groups of people, PrEP is not cheap. In fact, PrEP costs over $1,000 per month when paid out-of-pocket in the United States and it is often not covered by insurance. There is no question that the high cost of PrEP is going to stop a lot of at-risk people without insurance from using it. People without insurance will want to look for free or subsidized options to get the medication.
PrEP Rx – How To Get A PrEP Prescription
Now that you understand more about pre-exposure prophylaxis, you might be wondering how you can get a PrEP prescription. PrEP can be prescribed by most doctors and other licensed medical providers and is often available at public health and sexual health clinics (call for availability). Again, realize that the high cost of the PrEP medication itself may warrant looking for places that can provide the medication for free or for a low cost.
PrEP vs PEP – What’s The Difference?
Many people who have heard of PrEP may have also heard of PEP. So what’s the difference? PrEP stands for pre-exposure prophylaxis while PEP stands for post-exposure prophylaxis. In the context of PrEP and PEP, the “exposure” is exposure to HIV that could lead to a permanent infection. PrEP is medication that is taken before a potential exposure occurs. PEP represents medications that are taken after the exposure has already occurred. Post-exposure prophylaxis is a way of reducing the risk of an infection by getting the medication at a high dose in at-risk areas after a possible exposure.
PrEP & You
PrEP is a valuable protective measure for people who have a partner who is HIV-positive or are in other high-risk situations. PrEP is not 100% effective, however, and will not protect against other types of sexually transmitted diseases. People using PrEP should still be thoughtful about using it regularly AND minimizing the risk of HIV exposure whenever possible.
- Okwundu CI, Uthman OA, Okoromah CA. Cochrane Database Syst Rev. 2012 Jul 11.
- Grant RM et al.N Engl J Med 2010; 363:2587-2599.
- McCormack S et al. The Lancet 2016; 387:53-60.