Pre-exposure prophylaxis (PrEP)
7-minute read
Key facts
- Pre-exposure prophylaxis (PrEP) is a medicine you take to lower your chance of catching HIV.
- PrEP is advised for people at risk of catching HIV — for example, men who have sex with men.
- PrEP is usually taken as a tablet every day.
- You can get a prescription for PrEP from your doctor.
- After you start taking PrEP, you will need to visit your doctor every 3 months for a check-up.
What is PrEP (pre-exposure prophylaxis)?
Pre-exposure prophylaxis (PrEP) is a medicine you can take to lower your chance of catching human immunodeficiency virus (HIV).
PrEP is advised for people who are at risk of HIV infection or have fears about catching HIV.
PrEP is not advised if you already have HIV.
It’s important not to confuse PrEP with PEP (post-exposure prophylaxis). PEP is a short course of anti-HIV medicines you can take if you may have been exposed to HIV. To work well, you must start PEP within 72 hours of exposure.
How does PrEP work?
PrEP contains 2 antiretroviral medicines that lower your chance of getting infected with HIV. Antiretroviral medicines work by stopping the virus from replicating (making copies of itself) in your body.
PrEP can lower your risk of HIV infection from sexual activity by 99%. It can also lower your chance of getting HIV from injecting drugs by 74%.
PrEP will not work as well if it is not taken as prescribed by your doctor.
If you already have HIV, PrEP is not advised. You will need other medicines to treat your HIV infection.
PrEP does not protect you against other STIs (sexually transmitted infection). You should still use a condom when you have sex.
What is PrEP used for?
PrEP is advised for people who are at risk of getting HIV, including:
- men who have sex with men
- people with a history of sexually transmitted infections (STIs) — such as anorectal gonorrhoea and chlamydia
- people who use illicit drugs — particularly crystal meth (ice) and injected drugs
- sex workers
- some transgender and heterosexual people who engage in high-risk behaviours
Your doctor can help you decide if PrEP is right for you.
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What forms of PrEP are available?
In Australia, PrEP comes as a tablet or injection. However, injectable PrEP is not subsidised (partly paid for) by the government through the Pharmaceutical Benefits Scheme (PBS).
The tablet is taken once a day. Ideally, you should take it with food.
What are the possible side effects or risks of PrEP?
PrEP can cause some rare side effects such as:
- headaches
- nausea
- feeling gassy (flatulence)
- kidney problems
- liver problems (very uncommon)
Most of these side effects go away within a month of starting PrEP. Your doctor will talk about these with you.
How do I take PrEP?
PrEP can be taken daily or on-demand. Your doctor will suggest the best way for you.
It’s very important you take your PrEP exactly as your doctor says. This will give you the best protection from HIV.
Ask your doctor how long you need to take PrEP for before it will work.
Daily PrEP
Taking your PrEP medicine every day is the most common way to take PrEP in Australia.
Guidelines say that doctors should offer daily PrEP to all people at risk of HIV infection.
Start PrEP at least 7 days before potential HIV exposure.
On-demand PrEP
Taking PrEP on-demand is only advised for cis males who have sex with other males. There is not enough research to show that this works to stop HIV infection in other groups of people.
You must follow a special protocol for on-demand PrEP:
- Take 2 tablets at least 2-24 hours before sex.
- Take another tablet 24 hours later.
- Take another tablet another 24 hours later.
If you keep having sex, take another tablet every 24 hours, for ongoing protection. Continue to take your tablet for another 2 days (1 tablet each day) after the last sexual activity.
If you are living with chronic hepatitis B, on-demand PrEP is not suitable for you. Ask your doctor about other options.
When should I see my doctor?
Before your doctor gives you a prescription for PrEP, they will check if you have:
- HIV
- other STIs — including gonorrhoea, chlamydia and syphilis
- hepatitis A, hepatitis B (HBV) and hepatitis C (HCV)
Your doctor will also check:
- your kidney function
- your bone health
- if you are pregnant
Your doctor may suggest that you are vaccinated against hepatitis A and HBV. They will also talk about possible side effects of PrEP.
After you start taking PrEP, you will need to visit your doctor every 3 months for a check-up.
Where can I get PrEP?
There are a few ways you can buy PrEP.
PrEP can be prescribed by any doctor or authorised nurse practitioner. Australian residents with a current Medicare card can get PrEP through the Pharmaceutical Benefits Scheme (PBS). You will need to make a co-payment at the pharmacy.
You can get a private prescription from any doctor or authorised nurse practitioner. You may want to do this if you do not have access to Medicare. The cost for the medicine is higher than if you get it through the PBS.
You may want to import a generic version of PrEP from a trusted overseas supplier. This can be a good solution if you:
- are not eligible for Medicare
- find the cost of PrEP through private prescription too high
You can even buy a few months' worth of PrEP at once to save money on shipping costs.
You still need a prescription from your doctor. You can visit the PrEPaccessNOW website to learn more about buying PrEP.
FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.
Resources and support
Learn about different ways to get PrEP at the PrEP Access Now website.
Visit Health Equity Matters, an Australian non-profit organisation that gives a voice to communities affected by HIV/AIDS.
Read the PrEP patient information booklet at NSW Health — this booklet also talks about PrEP, pregnancy and breastfeeding.
Visit Get PrEP'D to learn more about ways to prevent HIV. Get PrEP’D is for gay, bisexual and other men who have sex with men to find out about PrEP.
You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.
Other languages
The Victorian Sexual Health Network website has fact sheets on HIV in Arabic, Chinese, Korean and Spanish.
Ending HIV has fact sheets on PrEP in Arabic, Chinese, Indonesian and Spanish.
Aboriginal and/or Torres Strait Islander peoples
Visit U & ME CAN STOP HIV for resources on HIV for Aboriginal and/or Torres Strait Islander people.