Couple hugging after treatment from doxycycline for STDs

Doxycycline for STDs: What It Is and How It Works

Written on July 18, 2023 by Gillian (Gigi) Singer, MPH, Sexuality Educator & Certified Sexologist. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

What Is Doxycycline?

Doxycycline is an antibiotic, meaning it “is used to treat a variety of infections caused by certain types of bacteria.”[1] This type of drug “is in a class of medications called tetracycline antibiotics,” which work “to treat infections by preventing the growth and spread of bacteria.”[1]

It works to treat acne by killing the bacteria that infect pores and decreasing a certain natural oily substance that causes acne. It works to treat rosacea by decreasing the inflammation that causes this condition.[1] Doxycycline does not kill viruses and thus does not work for colds, influenzas (flu), or other infections caused by viruses.[1]

How Is Doxycycline Used?

In previous and current practice, the drug is most often used for the following[1]:

  • “To treat or prevent anthrax (a serious infection that may be spread on purpose as part of a bioterror attack) in people who may have been exposed to anthrax in the air.”
  • “To treat plague and tularemia (serious infections that may be spread on purpose as part of a bioterror attack).”
  • “To prevent malaria.”
  • “To treat acne and rosacea (a skin disease that causes redness, flushing, and pimples on the face).”
  • “To treat Lyme disease or to prevent Lyme disease in certain people who have been bitten by a tick”

The drug can be taken by mouth in the form of a capsule, tablet, delayed-release tablet, or liquid suspension.

Medline Plus recommends that you “drink a full glass of water with each dose. If your stomach becomes upset when you take doxycycline, you may take it with food or milk. Talk with your doctor or pharmacist about the best way to take doxycycline. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take doxycycline exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.”[1]

Doxycycline can decrease the effectiveness of hormonal contraceptives (birth control pills, patches, rings, or injections), can affect pregnancies, and can be problematic for fetuses and children under the age of 8.[1]

Use of Doxycycline for STDs

The use of doxycycline for sexually transmitted diseases (STDs) and sexually transmitted infections (STIs) is a relatively new practice that is being studied. During the 2022 International AIDS Conference, scientists presented findings from a study funded by The National Institute of Health (NIH), which examines “the use of doxycycline post-exposure prophylaxis (doxy-PEP) to prevent these infections,” referring to gonorrhea, chlamydia, and syphilis infections.[2]

Private STD consultations

If post-exposure prophylaxis or PEP sound familiar, that’s because this terminology is regularly used in conversations about HIV prevention. Currently, PEP refers to a medication that is taken to prevent the contraction of HIV following a potential exposure. In the case of doxy-PEP, the drug would also be taken after a potential exposure to the bacterial infections. Prophylaxes are means of prevention, and “post-exposure” refers to when the drug is administered.

The CDC summarizes the data presented to them about doxy-PEP: “The first look at the data presented at the 2022 International AIDS Conference showed doxy-PEP demonstrated significant effectiveness and tolerability against these common STIs in gay and bisexual men and transgender women with HIV or taking HIV pre-exposure prophylaxis (PrEP) over the course of this study.”[2] The study treats “Doxy-PEP as a targeted intervention for bacterial STIs has the potential to reduce STI acquisition and transmission.”[2]

Why Investigate New Treatment Methods for STIs?

The United States is battling with increased levels of antibiotic-resistant types of sexually transmitted infections (STIs), specifically chlamydia, gonorrhea, and syphilis. These three STIs “are all caused by bacteria and are generally curable with antibiotics. However, these STIs often go undiagnosed and are becoming more difficult to treat, with some antibiotics now failing as a result of misuse and overuse.”[3] The WHO continues, “Resistance of these STIs to the effect of antibiotics has increased rapidly in recent years and has reduced treatment options. Of the 3 STIs, gonorrhea has developed the strongest resistance to antibiotics. Strains of multidrug-resistant gonorrhea that do not respond to any available antibiotics have already been detected. Antibiotic resistance in chlamydia and syphilis, though less common, also exists, making prevention and prompt treatment critical.”[3]

It is crucial that we have an effective way to treat and cure bacterial STDs like chlamydia, gonorrhea, and syphilis.

If you're looking for fast and discreet STD care, Everlywell offers access to STI treatment online via telehealth.

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  1. Doxycycline. MedlinePlus. Accessed July 14, 2023.
  2. CDC response to doxy-PEP data presented at 2022 international AIDS conference. Centers for Disease Control and Prevention. July 27, 2022. Accessed July 14, 2023.
  3. Growing antibiotic resistance forces updates to recommended treatment for sexually transmitted infections. World Health Organization. Accessed July 14, 2023.
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