The information below has been collated from various reputable sources including the World Health Organization, US Centers for Disease Control and Prevention, Planned Parenthood and PrEP Facts.
What is PrEP?
PrEP is a pill you can take to protect yourself from HIV. When used as directed, PrEP has been shown to be highly effective at reducing the risk of contracting HIV - up to 99% in some cases.
PrEP stands for Pre-Exposure Prophylaxis - meaning a treatment or action you take before risk of exposure (in this case to HIV) to prevent disease. It is different from PEP (Post-Exposure Prophylaxis).
What PrEP contains and how it works
PrEP is currently available in two forms - the branded drug Truvada, and unbranded generic forms. Two widely used versions of generic PrEP are Tenof-EM (from Hetero Drugs) and Tenvir-EM (from Cipla), both of which are approved by the US FDA.
Generics contain exactly the same active ingredients as Truvada (Tenofovir TDF and Emtricitabine FTC), and work in the same way - by stopping the virus from replicating in your body. They are manufactured by companies that do not own the original patent.
However, Truvada is significantly more expensive than generics, in some cases costing up to $1,800 a month. This is because pharmaceutical companies that invent original brand-name drugs need to recoup their costly investment in the development process, while generic manufacturers only need to demonstrate to regulators that their version is as good and effective as the original.
Tenof-EM is equivalent to Truvada and other generics including Ricovir-EM and Tenvir-EM.
Why take PrEP?
For those at high risk of HIV, taking PrEP can significantly reduce the risk of infection if taken daily.
The use of PrEP is currently recommended in national guidelines in many countries including the United States, United Kingdom and Australia. The World Health Organization recommended in 2015 that “PrEP should be offered as an additional prevention choice for people at substantial risk of HIV infection as part of combination HIV prevention approaches”.
Several studies on PrEP have been carried out in recent years, conclusively proving the effectiveness of the drug in preventing HIV. These studies include the following:
| Study | Key details |
|---|---|
| iPrEx study | - Conducted among 2499 men and transgender females - Protection against HIV infection was significantly higher among study participants who took the drug regularly enough to have detectable drug concentrations in their systems, as measured through blood analysis |
| IPERGAY study | - Conducted among 414 MSM comparing on-demand PrEP vs placebo - Study found a relative reduction in HIV infections of 86% for those taking PrEP on-demand vs the placebo group |
| PROUD study | - Conducted among 544 MSM in England - Participants either received daily PrEP immediately or after a deferral period of 12 months - Study found that daily PrEP conferred even higher protection against HIV than in placebo-controlled trials, without evidence of an increase in other sexually transmitted infections |
You should consider taking PrEP if you:
- Have sex with a person with HIV who is not on suppressive Antiretroviral Therapy (ART) or has a detectable viral load
- Have anal or vaginal intercourse without consistent use of condoms with more than one partner
- Have difficulties or concerns using condoms
- Use recreational drugs (chemsex)
PrEP is not suitable if you:
- Have a known HIV infection
- Have clinical symptoms that suggest acute HIV infection or HIV seroconversion illness
- Have known impairment of renal (kidney) function
- Have an allergy to any of the drugs in the PrEP regimen
How to take PrEP
How you take PrEP depends on how far in advance you plan on having sex and how regularly you have sex, but does not necessarily depend on how much sex you have.
There are two key ways to take PrEP:
- Recommended if you want the peace of mind and relief from stress of trying to stay HIV negative
- Take one pill every day at the same time each day
- Suitable for both anal and vaginal sex
- You can miss a pill from time to time and still have adequate protection
- Recommended if you know that you might have condomless sex 24 hours in advance
- Take two pills 2 - 24 hours before sex, then take 1 pill 24 hours later, and 1 more pill 24 hours after that
- If having sex for an extended period of time, continue to take a pill every 24 hours until you have 2 sex-free days
- Only suitable for anal sex, not vaginal sex
- Important not to miss any doses
PrEP should be taken as part of a comprehensive HIV / STI prevention plan. It is highly effective only if taken as prescribed above, and it is important to get tested regularly for HIV / STIs, monitor side-effects, and obtain new prescriptions (if necessary).
PrEP does not prevent other STIs, and it is highly encouraged that you maintain the use of condoms to the extent possible. PrEP also does not prevent pregnancy, and contraception should be used to prevent pregnancy if needed.
PrEP risks and side effects
PrEP only protects you against HIV but not other sexually transmitted infections (STIs) such as gonorrhoea, chlamydia, syphilis and hepatitis C.
In some cases, PrEP can cause minor side effects like nausea, vomiting, fatigue and dizziness, but these usually disappear over time. In very rare cases, PrEP can also affect kidney functions.
If you’re taking PrEP and experience any side effects that are severe or don’t go away, inform your healthcare professional.
Before starting PrEP
It is essential that you undergo a few tests before or as you start PrEP.
Most importantly, PrEP can only be used if you are HIV negative. If you are already HIV positive and don’t realise it, you could develop resistance to drugs that you will need for treatment.
We highly encourage you to approach your healthcare provider for the following tests before purchasing and using PrEP:
- 4th generation HIV test - if your last high-risk exposure was within the last 4 weeks, repeat this test after 4 weeks to make sure an acute or recent HIV infection was not missed out
- Renal (kidney) function test - you should not be taking PrEP if you have existing kidney problems or are taking medication that may affect your kidneys
- Hepatitis B and Hepatitis C tests
- Sexually Transmitted Infection (STI) screening
After starting PrEP
4 weeks after starting on PrEP, the following check-in with your healthcare provider is recommended:
- Repeat 4th generation HIV test
- Review adherence to daily or on-demand PrEP regimen
Subsequently, it is recommended that you visit your healthcare provider regularly for the following tests while on PrEP:
| Test | Frequency |
| 4th generation HIV test | Every 3 months |
| Sexually Transmitted Infection (STI) screening | Every 3 - 6 months, depending on your sexual risk behaviour |
| Renal (kidney) function test | Every 6 months |
| Hepatitis C test | Every 12 months |
If you decide to stop PrEP, you should continue taking daily PrEP for 2 days after anal sex and for 7 days after vaginal sex. Subsequently, you should also assess your HIV status with a 4th generation HIV test after stopping PrEP.
Other resources
The information above has been collated from sources including the following, which you can read through if you wish to find out more about PrEP:
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