What is HIV Pre-Exposure Prophylaxis (PrEP)?
HIV Pre-Exposure Prophylaxis (PrEP) is the use of medications to effectively prevent the transmission of HIV. Individuals who are taking PrEP can reduce their risk of contracting HIV infection by up to 99% if taken regularly. This type of medication must be taken before exposure to be effective. It is different from Post-Exposure Prophylaxis (PEP), which is taken immediately after possible exposure and uses additional medications.
PrEP is usually taken as a once-daily combination tablet of tenofovir disoproxil fumarate (TDF) + emtricitabine (brand name: Truvada), although other types of dosing regimens are available as well depending on the unique lifestyle of the individual. Studies have shown that PrEP is generally safe for long term use, but some may experience side effects such as a reduction in kidney function and bone density.
The FDA recently approved a new drug combination of tenofovir alafenamide (TAF) + emtricitabine (brand name: Descovy) for use as PrEP, which has shown to be equally effective in preventing HIV infection whilst touting an improved safety profile for renal and bone toxicity.
The main difference between Descovy and Truvada is the form of tenofovir drug present – the newer Descovy uses TAF, which enters cells more efficiently than Truvada’s TDF, and means that a much lower dose of tenofovir is needed. This means that other tissues such as the kidney and bone are exposed to a much lower dose of the drug and there is less risk of drug toxicity.
The DISCOVER trial for Descovy as PrEP showed that the new drug is as effective as Truvada in preventing HIV transmission in men or transgender women who have sex with men, when taken as a once-daily tablet. They have not yet performed specific studies to evaluate protection in vaginal sex, or with other PrEP dosing schedules (such as Event-Based Dosing, T’s and S’s, etc.).
However, given that Descovy is essentially just a new and improved Truvada (which has been extensively studied in these situations), it is likely just a matter of time before further studies are done and show similar efficacy.
Descovy also includes a warning in usage as PrEP for patients with known hepatitis B infection, stating a potential risk of hepatitis B exacerbation after stopping the drug. While it can still be used as PrEP in patients with a history of hepatitis B infection, close monitoring of liver function and hepatitis B viral load for up to 6 months following discontinuation of Descovy is recommended (same as Truvada).
Speak To Our Doctors Today!
Descovy is currently available in all Dr Tan & Partners (DTAP clinics) in Singapore. It is a prescription-only medication and must be prescribed by a doctor. Speak to our doctors for more information about Descovy and find out if a HIV-1 treatment that contains Descovy is right for you. Dr Jonathan Ti, MB, BCh, BAO (Ireland), MRCP (UK), Cert. Men’s Health, is a member of the Singapore HIV PrEP Taskforce and is a co-author of the Singapore HIV PrEP Guidelines and is currently practising at our Robertson Walk Clinic.
HIV PrEP does not protect the user against other STDs. Therefore, even if you are on HIV PrEP, it is important to still to use a condom regularly, as well as get your regular STD screening & HIV Testing.