What are the differences between DoxyPEP, PrEP, and PEP? A comparative guide to HIV and STI prevention medications
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"What's the difference between Doxy-PEP and PEP?" "I thought taking PrEP would prevent STIs." "I don't know which one to use." — There are multiple medications for STI prevention, and many people get confused.
Doxy-PEP, PrEP, and PEP differ completely in the infections they target, when they are taken, and their purpose. To choose the prevention method that's right for your situation, it's essential to correctly understand their differences.
In this article, a doctor from Mona Aoyama Clinic will clearly explain the differences between the three preventive medications using a comparison table, and help you determine which medication you need.
Three Preventive Medications – Comparison Chart
| Item | Doxy-PEP | PEP | PrEP |
|---|---|---|---|
| Purpose | STI prevention (post-exposure) | HIV prevention (post-exposure) | HIV prevention (pre-exposure, ongoing) |
| Active Ingredients | Doxycycline | Tenofovir + Emtricitabine (+ Integrase Inhibitor) | Tenofovir + Emtricitabine |
| Timing of Administration | Once, within 72 hours after sex | Daily for 28 days, within 72 hours after sex | Daily, starting before sexual activity and continuing |
| Target Infections | Chlamydia, Syphilis, Gonorrhea | HIV | HIV |
| Effectiveness against HIV | None | High (approx. 80-90%+) | High (approx. 99% with daily use) |
| Impact of Missed Doses | Single dose, less likely to miss | Must be taken daily; effectiveness decreases if missed | Must be taken daily; effectiveness decreases if missed |
| Prescription Format | Our clinic: Online prescription, same-day shipping | Our clinic: Online prescription, same-day shipping | Our clinic: Online prescription, regular prescription |
The combination drug of "tenofovir + emtricitabine" used in PrEP and PEP is known by the brand name "Truvada" for its originator product. In recent years, the improved version "Descovy" has also been used.
Who Each Medication Is Suitable For
Who Doxy-PEP is suitable for
- Individuals who have had condomless sex and are concerned about chlamydia, syphilis, or gonorrhea.
- Individuals who have been infected with an STI within the past 12 months.
- Individuals using PrEP but are concerned about STIs other than HIV.
- MSM (men who have sex with men) or transgender women.
Who PEP is suitable for
- Individuals who have had sexual activity with a risk of HIV exposure and are within 72 hours of the event.
- Individuals whose condom broke or came off during sex with an HIV-positive partner.
- Individuals in an emergency situation requiring immediate HIV prevention.
Who PrEP is suitable for
- Individuals who consistently have sexual activity with HIV risk (and can adhere to daily medication).
- Individuals who have sex with an HIV-positive partner.
- Individuals who frequently use PEP (consider switching to PrEP).
If You're Concerned About Both HIV and STIs
Doxy-PEP and PEP can be used simultaneously. If there is a risk of both HIV exposure and exposure to chlamydia, syphilis, etc. (e.g., condomless sex with multiple partners), combining both can provide broad prevention.
💡 For PrEP users: PrEP prevents HIV, but it is not effective against chlamydia, syphilis, or gonorrhea. Using Doxy-PEP in parallel with PrEP can cover overall STI prevention. Our clinic offers combination plans.
Cost Comparison (at Our Clinic)
| Drug | Estimated Cost (incl. tax) | Duration of Use |
|---|---|---|
| Doxy-PEP (3 doses) Regular | 600 yen/dose* | One dose as needed |
| PEP (28 days) | 17,250 yen/month | Daily for 28 days |
| PrEP (1 month) Regular | 1,706 yen/dose* | Daily, ongoing |
*Please check each product page for the latest prices.
*Prices are for Doxy-PEP 100-dose bulk purchase, PEP divided into 4 payments, and on-demand PrEP with a 3-month regular subscription.
If You're Undecided – Conclusion on How to Use the Three
The basic usage is Doxy-PEP for isolated risks, PEP for urgent HIV risks, and PrEP for ongoing HIV risks. If multiple risks overlap, it's possible to prescribe a combination rather than sticking to a single drug. If you're unsure, please explain your situation during the consultation, and the doctor will suggest the optimal combination.
Frequently Asked Questions
No, it does not. PrEP only prevents HIV. Doxy-PEP is necessary to prevent chlamydia, syphilis, and gonorrhea. Co-administration of Doxy-PEP is recommended for PrEP users.
Yes, it is fine. If you are concerned about both HIV and other STIs, both can be prescribed. At our clinic, you can consult and get prescriptions for both online.
If you are using PEP more than once a month, it is worth considering switching to PrEP. PrEP, when taken daily, has very high effectiveness in preventing HIV. Please consult us during your examination.
Related Columns
Doxy-PEP Complete Guide – What Doxy-PEP is, its effects, how to take it, side effects, and online prescription explained by a doctor /
Doxy-PEP and Drug Resistance – Understanding and Using Safely | Mona Aoyama Clinic
