For people who have anal sex, PrEP becomes very effective after seven days if it is taken every day. It takes longer to become effective (21 days of daily use) to be effective in preventing HIV after medication injection or in people who have vaginal sex. Research suggests that PrEP is less effective when not taken daily. This may be because there is not enough medication in your body to prevent HIV from taking root and spreading.
Along with the use of PrEP, taking steps such as using condoms can further reduce the risk of HIV infection. PrEP doesn't prevent other sexually transmitted infections, so you'll need to have safe sex. The PrEP drug must reach and maintain a certain level in the blood and mucous membranes of the body to provide protection. The amount of time it takes can vary from person to person.
For people who take PrEP daily and who have anal intercourse, the drug should be taken every day for 7 days to reach the level necessary for full protection. Cis-gender MSM who take PrEP on demand should take two pills, 2 to 24 hours before having sex. For the receptive partner in vaginal intercourse, it takes about 20 days of taking the drug consistently to achieve the level of full protection in the female genital tract. This is why cisgender women and transgender men who have receptive vaginal sex should not take PrEP on demand.
People with transgender experience should talk to their health care provider about their specific sexual practices to better determine how long it will take to be fully protected. PrEP is very effective in preventing HIV when taken as directed. PrEP reduces the risk of contracting HIV through sexual intercourse by approximately 99% when taken according to. Among people who inject drugs, it reduces risk by at least 74% when taken as prescribed.
PrEP is much less effective when it is not taken consistently. PrEP reaches its maximum effectiveness after seven days for anal sex and 21 days for vaginal sex or injecting drug use. Skipping doses or not using additional protective measures until you reach these points makes PrEP much less effective. PrEP is very effective in preventing HIV.
When PrEP is taken as prescribed daily, it reduces the risk of contracting HIV by 99%. PrEP is even more effective when combined with other protections, such as condoms. Although it can also be prescribed as PrEP on demand. Among homosexual men considered to be the highest risk level, PrEP use was associated with an estimated 86% protective benefit compared to non-PrEP counterparts.
Hormones taken by transgender women seem to reduce levels of the PrEP drug tenofovir slightly, but not enough to affect the effectiveness of daily PrEP. It's important to talk to your healthcare provider about whether daily PrEP or on-demand PrEP is right for you. Generally speaking, cisgender men who take PrEP on demand should continue to take PrEP medication for at least 2 days after any possible exposure. In people who can take PrEP regularly, and only occasionally skip doses, PrEP seems to prevent nearly 100% of infections.
Which PrEP option is available and best for you depends on where you live, who you are, and how you want to use PrEP. It's important to weigh the pros and cons and have an open and honest discussion about PrEP with your healthcare provider before starting PrEP. Many transgender people considering PrEP are concerned about side effects and drug interactions and, in particular, whether PrEP medications could interfere with gender-affirming hormone therapy. If you want to stop taking PrEP for any reason, talk to the health care provider who prescribed it or another provider who is familiar with PrEP.
The Department of Health and Human Services' Ready, Set, PrEP program that offers PrEP at no cost to people without prescription drug coverage. You can ask your healthcare provider if there are any PrEP programs or trials through which you can access PrEP free of charge. Canadian PrEP guidelines recommend that people who inject drugs consider PrEP if they are at high risk of contracting HIV. .