PrEP, or pre-exposure prophylaxis, is a single-dose daily regimen that can protect HIV negative individuals from contracting HIV from sexual intercourse and intravenous drug use. This guide can help you better counsel patients who express interest in this promising new HIV prevention tool.The American Center for Disease Control is still finalizing guidelines for PrEP. In the meantime, they have released the following interim guidelines specifically for men who have sex with men, heterosexual adults and injection drug users.
What is PrEP and How Does it Work?PrEP is not the name of a specific drug but rather refers to what the drug is used for, which in this case is preventing the transmission of HIV. The only medication that has been approved for HIV prevention is a fixed-dose combination of tenofovir disoproxil fumarate and emtricitabine, which is marketed as PrEP therapy in the U.S. The American FDA has also allowed pharmaceutical companies in other parts of the world to market generic versions of PrEP. The drugs that make up PrEP are antiretrovirals that have been used as part of HIV treatment for several years. Tenofovir disoproxil fumarate is also used to treat hepatitis B.If an HIV-negative person who is taking PrEP is exposed to the semen or vaginal fluids of an HIV positive person, PrEP can prevent HIV from replicating and therefore prevent lasting infection.
The Effectiveness of PrEPTwo large scale studies found that patients who took PrEP every day reduced their chances of contracting HIV from sexual intercourse by up to 99 percent. PrEP proved equally effective in men and women who engaged in vaginal and anal sex with and without condoms. Other studies have found that PrEP can prevent transmission of HIV through intravenous drug use by 75 percent. Based on these results, the U.S. FDA approved PrEP for HIV negative adults who are at high risk for contracting HIV. You can read more details about PrEP research in this guidebook.
In addition to taking a pill every day, patients on PrEP should also see a doctor at least every three months for routine blood work including an HIV test and an analysis of kidney functions.
The Difference Between PrEP and PEP
PrEP must be taken every day for at least seven days before an HIV exposure to prevent infection. PEP, or post-exposure prophylaxis, is a month-long course of drugs that must be started within 72 hours after an HIV exposure to prevent infection.
Determining Who Should Take PrEP
If a patient answers "yes" to any of the following questions, they can likely benefit from taking PrEP:
- Do you have a primary sexual partner who is HIV-positive?
- Have you recently had vaginal or anal intercourse without a condom with someone whose HIV status you are unsure of?
- Have you recently been treated for another STI?
- Have you previously used PEP more than once?
- Have you or your sexual partners been in prison?
- Do you or your sexual partners frequently use drugs or alcohol?
- Do you or your sexual partners ever exchange sex for money or other needs?
- Has your partner physically harmed you or threatened to physically harm you recently?
- Are you in a serodiscordant relationship and you or your partner are trying to get pregnant?
- Do ever use injection drugs?
Not everyone who affirmatively answers these questions needs to start PrEP. Many patients can effectively use other risk reduction techniques, such as consistent condom use, to protect themselves from HIV. PrEP is simply another option for risk reduction.
A patient should not start PrEP if they:
- Do not know their HIV status and are opposed to getting tested
- Are already HIV-positive
- Have recently had a suspected exposure and are showing signs of acute HIV infection such as a rash or flu-like symptoms
- Cannot locate a provider for ongoing blood monitoring and HIV testing while on PrEP
- Cannot commit to taking a pill every single day
- Do not know if they have hepatitis B and are opposed to getting tested
- Have an existing kidney impairment
Side Effects of PrEP
Minor short-term side effects sometimes occur when a patient starts taking PrEP, but they go away within a few weeks. These include headaches, weight loss and gastrointestinal disturbances.Some patients experience a slight reduction in bone mineral density while taking PrEP, but this symptom does not worsen over time, and bone density returns to normal after PrEP has been discontinued. In rare cases, PrEP can negatively impact kidney functions, which is why it is important for PrEP patients to get regular check-ups. HIV-negative patients with a creatinine clearance of less than 60 mL/minute should not take PrEP.
PrEP and Drug Resistance
One of the early concerns about PrEP is that improper adherence could lead to antiretroviral drug resistance should a patient contract HIV while on PrEP. No cases of drug resistance have been documented in patients who have contracted HIV while taking PrEP, but it remains a theoretical concern. This is another reason why strict, daily adherence to PrEP is so important.
PrEP and Interactions with Other Drugs
At this time, PrEP has no known interactions with alcohol, recreational drugs or other pharmaceuticals. Make sure to ask patients about all of the legal and illegal drugs they use, and double check to make sure there are no documented side effects.
The Importance of Testing for Hepatitis B Before Beginning PrEP
The drugs in PrEP are also used to treat hepatitis B; however, they may not be effective at controlling hep B on their own. Taking PrEP while infected with hep B can cause the patient to become resistant to other hep B medications. Furthermore, if a person infected with hep B suddenly stops taking PrEP, they can experience a sudden and dangerous inflammation of the liver. For these reasons, patients should get tested for hep B before starting PrEP.If the patient tests negative for hep B, they should be encouraged to get vaccinated for it while on PrEP. Patients with hep B can take PrEP, but they should be carefully monitored for complications.
The Importance of AdherenceFor maximum protection against HIV, PrEP must be taken daily. PrEP may still lower a patient's risk if taken inconsistently, but their chances of contracting HIV increases with each missed dose. Providers can help patients brainstorm methods for helping them remember to take their medication such as setting a cell phone alarm, downloading an app for medication reminders or associating taking PrEP with a daily routine like brushing their teeth.
Discontinuing PrEPPrEP may be discontinued at any time without fear of withdrawal symptoms. If a patient tests positive for HIV while taking PrEP, they must begin additional antiretroviral treatment to prevent HIV from progressing to AIDS. If a patient expresses interest in stopping PrEP, make sure to talk to them about other HIV prevention strategies.If a patient with hepatitis B wishes to discontinue PrEP, they must be carefully monitored for liver complications.
PrEP and Condom UseCondoms are highly effective at preventing the transmission of HIV; however, many people struggle with consistent condom use for a variety of reasons, and PrEP provides those people with a viable alternative.It is vital to point out to patients that PrEP does not provide protection from pregnancy or other STIs, so condom use is still highly encouraged in many situations. Some providers may worry that PrEP will give patients an excuse to not use condoms, but studies have actually suggested the opposite: Many patients taking PrEP as part of clinical trials reported more consistent condom use, likely because they were being more conscious of their HIV risks. Nonetheless, many people still choose not to use condoms, and denying them a scientifically proven HIV prevention drug such as PrEP would be unethical.
Insurance and the Cost of PrEPMany private insurance plans cover PrEP, but some do not. Medicaid may cover PrEP in some states but not others. Within the U.S., there is only one PrEP drug approved for sale. The manufacturer offers financial assistance for patients with and without insurance. The current out-of-pocket cost of PrEP therapy is about $13,000 per year. For this reason, the FDA has allowed drug manufactures in other parts of the world to produce generic versions of PrEP, and many patients choose to import these drugs from abroad for financial reasons. Patients should be encouraged to only buy from reputable distributors and to continue getting routine check-ups while on PrEP. For convenience, here is a link to a reputable website that Australian ASO's are referring patients to: Generic PrEP - Tenvir EM
Patient ReferralIf you have a patient who wants more information about PrEP than you can provide, you can refer them to their local health department or an infectious disease specialist. You can also refer them to the AIDS Vaccine Advocacy Coalition website, which keeps a database of ongoing clinical trials for PrEP.
For additional guidance on prescribing PrEP, you can contact the CDC or the National HIV/AIDS Clinicians’ Consultation Center’s Warmline.