A daily PrEP regimen involves the person taking a single daily tablet at approximately the same time each day see figure 6.1. Taking the tablet some hours earlier or later than usual will not adversely influence the levels of the drug. If the person forgets to take a tablet for one day, there is no need to take two tablets the next day.
The on-demand† PrEP regimen, which is recommended for cis-gender MSM only, involves the person taking a loading dose of PrEP where two tablets of PrEP are taken together as early as 24 hours before sex, or as late as 2 hours before sex (figure 6.2). After sex, another PrEP tablet is taken 24 hours after the loading dose and then a final PrEP tablet is taken 48 hours after the loading dose. This 2+1+1 method for the use of on-demand† PrEP for an isolated act of sex was recently endorsed by WHO (6).
If more sex acts take place over the following days, a single PrEP pill can be continued daily for as long as sex continues, with a single daily pill taken for each of two days after the last sex act.
† The Therapeutic Goods Administration (TGA) has not approved this regimen in Australia.