Can I Take PEP Four Days After Exposure?

In this article, we'll answer your most pressing questions about PEP and how long it can be taken and remain effective after exposure.

What is PEP?

PEP is an acronym for post-exposure prophylaxis. It refers to a combination of medications that are taken by an HIV-negative person after exposure to HIV.When taken correctly and in time, these medications can prevent HIV. 

PEP is distinct from PrEP, or pre-exposure prophylaxis, which is a daily medication. PrEP can be taken regularly in advance of exposure to prevent HIV. 

How long does PEP last in the body?

PEP medications must be taken daily for one month or 28 days to be effective. PEP does not remain active in the body after this regular course. This means that once you stop taking PEP, you can contract HIV again if exposed to it.

Can I take PEP four days after exposure?

PEP is most effective when taken within 72 hours, or three days, of potential exposure to HIV. The sooner you take PEP, the better. At four days after exposure, PEP is less likely to be effective. If more than 72 hours have passed and you have not started PEP, it's important to seek the advice of a healthcare practitioner to determine the best next steps.

Can you take PEP six days after exposure?

Since PEP is indicated to be taken within 72 hours, six days after exposure is too late to start taking PEP. A healthcare practitioner can help you determine the best course of action if you are at more than three days after exposure.

Can I take PEP after ten days?

If ten days have passed since HIV exposure, it's important to see a healthcare practitioner and to get tested. While PEP needs to be taken within 72 hours after exposure, you may be able to begin very early treatment with antiretroviral medications to limit the effect of HIV on your immune system.

What happens after you finish taking PEP?

After you finish taking PEP, the next step is to take an HIV test that can help determine if PEP is effective. If it is taken quickly enough after exposure, PEP prevents HIV from taking hold. However, getting tested just in case is important since it does not work in 100% of cases. 

After this initial test, you will likely be scheduled for a follow-up test after about 3 months. This can help conclusively determine that PEP worked. Since you won't be absolutely certain right away, it's a good idea to protect your partners and yourself by using condoms in the meantime.  

Does PEP cause permanent damage?

Taking a course of PEP as prescribed by your healthcare practitioner does not cause permanent damage. However, remember that PEP is not meant to be taken in the same way as PrEP. While PrEP can be taken as a daily medication, PEP is only meant to be taken in emergencies, not regularly. 

If you find that you require access to PEP regularly, PrEP may be a better choice that is safe and sustainable over the long term. 

Why is PEP Not Recommended?

PEP is not recommended for people with a regular, ongoing risk of being exposed to HIV. For these individuals, PrEP may be a more suitable option. However, for many people, PEP is a safe and effective course of medication that can dramatically reduce the risk of HIV.

How do I get PEP?

You can get PEP by obtaining a prescription from a licensed healthcare practitioner. Then, you can purchase it from any traditional or online pharmacy just as you would with any other prescription medication. Since taking PEP is time sensitive, make sure to use a pharmacy that stocks PEP.

Key takeaways

PEP, or post-exposure prophylaxis, can effectively prevent HIV if you have been exposed. However, it is most effective when taken right away. Efficacy steadily declines after 2 hours, and it must be taken within 72 hours, or three days, to be effective. 

This means that after four days, PEP may not be the best choice for you. A licensed healthcare practitioner can help you identify the best course of action if you are four days post-exposure.

Frequently asked questions

How effective is PEP after 24 hours?

PEP is very effective when taken within 24 hours. Since it is best taken within three days, 24 hours is well within the recommended window to begin taking PEP. While it doesn't 100% eliminate the risk of HIV, most people who take PEP within 24 hours of exposure will not become HIV positive.

What happens if I miss two days of PEP?

If you miss two days of PEP, the overall effectiveness of your treatment may decrease slightly. However, you should resume taking PEP and complete the full 28-day course.

How many times can you be on PEP?

While there isn't a strict limit to the number of times you can be on PEP, it is meant to be used in emergency situations rather than as a regular treatment. If you require PEP frequently, then it may be better to take PrEP, which is safe to take on an ongoing basis. 

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