Is Daily Tablet The Only Way To Take PrEP?

Short answer: no. Daily isn’t the only way to take PrEP.

For a lot of guys, daily PrEP is the simplest thing going. One tablet a day, set and forget, protected around the clock. But if your sex life is more occasional, or you just don’t love the idea of a pill every single day, there’s a second option that’s now standard in Australia. It’s called on-demand PrEP (you’ll also hear “event-based dosing” or “2-1-1”).

Here’s how it works.

On-demand PrEP: the 2-1-1 method

Three numbers, in order:

  • 2 tablets, taken together, 2 to 24 hours before sex.
  • 1 tablet 24 hours after that first double dose.
  • 1 tablet 24 hours after that (so 48 hours after the loading dose).

If sex keeps going across several days, carry on with one tablet every 24 hours, and take your last one 48 hours after the final time you had sex.

A worked example. You’ve got a date Saturday night. Take 2 tablets around lunchtime Saturday. Hook up that night. One tablet Sunday lunchtime, one tablet Monday lunchtime. Done.

Who on-demand is for

In Australia, on-demand PrEP is an option for cisgender men whatever the sex of their partners, and for people assigned male at birth who aren’t on oestrogen-based (feminising) hormones. ASHM updated this in 2025, so it now covers insertive vaginal sex too, not only anal. The strongest evidence comes from the IPERGAY trial in gay men having anal sex, which found this dosing cut the risk of HIV by around 86%.

If you have receptive vaginal or frontal sex, or you’re on oestrogen-based hormones, daily PrEP is the right option for you. The medication takes longer to reach protective levels in vaginal and frontal tissue, so the quick 2-1-1 load isn’t reliable there. (International guidelines use a longer event-based schedule for receptive vaginal or frontal sex, but Australian practice still defaults to daily for that. If that’s you and you’re curious, raise it with your doctor.)

A few things that matter

  • On-demand dosing only works with tenofovir disoproxil/emtricitabine (TDF/FTC) — the PrEP most people know as Truvada and its generics. It does not work with tenofovir alafenamide/emtricitabine (TAF/FTC), the type sold as Descovy. If you’re not sure which one you’re on, your doctor or pharmacist can tell you.
  • Set alarms for the 24 and 48 hour tablets. The most common way on-demand trips guys up: the sex is over, your brain moves on, and you forget the follow-up pills. Those follow-up pills are the protection.
  • It’s still a prescription medicine. You need to be HIV negative to start, and your doctor will check a few things first (including your hepatitis B status, because that affects whether on-demand is safe for you).

So, daily or on-demand?

Daily suits guys who have sex often, or who want one less thing to think about. On-demand suits guys whose sex is more occasional and you can see it coming. Both work. Both are subsidised on the PBS. And you’re not locked in. You can switch as life changes.

Want the full consent-level detail? Read the on-demand PrEP guide.

Talk to your doctor about which one fits your life.

Stay safe, team.

Dr George

This information is general in nature and not a substitute for personalised medical advice. PrEP is a prescription medicine. Speak to your doctor about whether it’s right for you and which dosing option suits your situation.

— Dr George Forgan-Smith, GP, practising in Sydney and Melbourne