Can amoxicillin treat STDs?

Amoxicillin is an antibiotic approved by the U.S. Food and Drug Administration (FDA) to treat many bacterial infections. These include ear infections, sinus infections, lower respiratory tract infections, and urinary tract infections (UTIs). It can also be combined with other medications to treat Helicobacter pylori infections and duodenal ulcer disease.

As one of the most common prescriptions in the nation, amoxicillin may be one of the first drugs people think of when they contract a sexually transmitted disease (STD). While amoxicillin can treat some STDs, such as chlamydia and gonorrhea, it typically isn’t the first-choice treatment. 

Read on to learn more about treating STDs with amoxicillin. 

Can amoxicillin treat STDs?

Amoxicillin is FDA-approved for treating nose, throat, ear, lung, skin, and urinary tract infections. It may also be prescribed off-label to treat other bacterial infections, including certain STDs. 

Antibiotics have to kill or stop bacteria from growing to treat infections. Amoxicillin belongs to a particular group of drugs called penicillin antibiotics, which block bacteria’s ability to make and repair their cell walls. Without cell walls, bacteria can’t survive and are more easily cleared by your immune system. 

Although amoxicillin isn’t the preferred treatment for any sexually transmitted infection, it may still be effective for treating chlamydia, gonorrhea, and syphilis. 

Chlamydia

Chlamydia is caused by the bacteria Chlamydia trachomatis and is one of the most common STDs, with more than 1.6 million cases in the U.S. in 2022. It’s spread during oral, vaginal, or anal sex and can affect both males and females. Chlamydia can also be passed from a pregnant woman to her baby during childbirth. 

According to the Centers for Disease Control (CDC), chlamydia often doesn’t cause symptoms, so many people don’t know they have it. Untreated chlamydia can cause serious health complications, such as permanent damage to a woman’s reproductive system, which can impact their ability to get pregnant in the future. If chlamydia symptoms occur, they may not start until several weeks after contracting the infection. Examples of chlamydia symptoms include pelvic floor pain, abnormal vaginal or penile discharge, burning sensation while urinating, or rectal pain, discharge, or bleeding. 

Although chlamydia has the potential to cause serious health problems if left untreated, the great news is it can be easily treated and cleared with the right oral antibiotics. However, antibiotics cannot reverse any permanent damage done by the disease. 

The treatment of choice for chlamydia in adults and teens is doxycycline. Alternative treatments include azithromycin or levofloxacin. 

The CDC doesn’t recommend amoxicillin for general chlamydia treatment. However, it is one of the treatment options for chlamydia in pregnant women. For pregnant women, the CDC recommends azithromycin. However, amoxicillin can be used as an alternative. 

RELATED: How to safely take antibiotics during pregnancy

Gonorrhea

Gonorrhea is caused by a bacteria called Neisseria gonorrhoeae and is another common STD, with more than 648,000 cases in the U.S. in 2022. It can be spread through any type of sexual contact and contact with the mouth, throat, eyes, urethra, penis, and anus. Similar to chlamydia, gonorrhea can also be spread from mother to baby during childbirth. 

Many cases of gonorrhea are asymptomatic. If present, signs and symptoms of gonorrhea can include a burning sensation during urination, abnormal discharge from the penis or vagina, vaginal bleeding between periods, or testicular or scrotal pain. Whether symptoms are present or not, untreated gonorrhea can cause serious health problems in both men and women. In women, it can lead to pelvic inflammatory disease (PID) and cause infertility. In men, untreated gonorrhea can cause epididymitis, which can lead to male infertility. In extreme cases, gonorrhea can spread to the blood and cause a life-threatening condition called disseminated gonococcal infection. 

Luckily, gonorrhea can be cured with antibiotics. But like chlamydia, permanent damage done by gonorrhea cannot be repaired by medications. The CDC recommends a single dose of ceftriaxone injection for the treatment of gonorrhea. Alternative treatments include gentamicin, azithromycin, and cefixime. 

Amoxicillin isn’t one of the CDC-recommended medical treatments for gonorrhea. However, there is some evidence that amoxicillin is effective in treating gonorrhea. 

Syphilis

Syphilis is an STD caused by the bacteria Treponema pallidum. In 2021, more than 176,000 new cases of syphilis were reported in the U.S., with 36% of all primary and secondary cases affecting gay, bisexual, and other men who have sex with men (MSM). Syphilis is spread by direct contact with an infected sore, which is called a chancre. Chancres can occur on the penis, vagina, anus, rectum, lips, or mouth. It can also be spread during vaginal, anal, or oral sex and from mother to baby during childbirth. 

There are four stages of syphilis, and the symptoms depend on which stage the disease is in. 

• Primary stage: You may notice one or multiple sores in, on, or around the penis, vagina, anus, rectum, or mouth. The sore is typically firm and painless and can heal on its own whether or not you receive treatment. 
• Secondary stage: You can develop skin rashes or sores in your mouth, vagina, or anus. The rash can be on your torso, palms, or soles of your feet and can appear rough, red, or reddish-brown. 
• Latent stage: Typically, there are no signs or symptoms of syphilis during the latent stage. But you can continue to have syphilis for years if left untreated. 
• Tertiary stage: Although most people don’t develop tertiary syphilis, if it does happen, it can affect the skin, bones, brain, and cardiovascular system. 

Without treatment, syphilis can also spread to the brain and nervous system, the eye, or the ear. 

The great news is syphilis can be cured with the right antibiotics, but treatment cannot undo any permanent damage the infection caused. According to the CDC, the preferred drug for all stages of syphilis is Bicillin L-A (penicillin G benzathine).

Although the CDC doesn’t recommend amoxicillin for the treatment of syphilis, there is some evidence that it can be an effective treatment in certain situations. These include the treatment of maternal syphilis and those with human immunodeficiency virus (HIV) and syphilis. 

Efficacy of amoxicillin for STD treatment

According to the CDC, the recommended treatment for chlamydia infections is doxycycline, and alternative drugs include azithromycin and levofloxacin. For the treatment of pregnant people with chlamydia, the treatment of choice is azithromycin, though amoxicillin is listed as an alternative treatment. In a 2001 study that compared azithromycin to amoxicillin for the treatment of chlamydia in pregnancy, cure rates of both drugs were high. Of the patients in the study who completed a follow-up test after finishing their antibiotic treatment, 20% of those who took amoxicillin still tested positive for chlamydia, compared with 5% of those who took azithromycin. 

The CDC recommends a single dose of ceftriaxone for the treatment of gonorrhea. Other recommended treatments include gentamicin, azithromycin, and cefixime. Although amoxicillin isn’t the treatment of choice for gonorrhea, there is some evidence that it’s effective against the infection. For example, a study from 1974 found amoxicillin to have a 95% cure rate when administered as a 3-gram single dose. The cure rate increased to 100% when amoxicillin 3 grams was given several doses over four days. 

In the U.S., the CDC recommends intramuscular penicillin G as the first-choice treatment for all stages of syphilis. However, in other countries, such as Japan and the United Kingdom, oral amoxicillin is recommended for syphilis treatment. In one study, amoxicillin plus probenecid demonstrated an overall cure rate of 94.4% in patients with HIV and syphilis. In another study, amoxicillin alone demonstrated an overall cure rate of 93.8% in patients with HIV and 100% in patients without HIV. 

Amoxicillin dosage for STD treatment

For the treatment of chlamydia in pregnant women, the CDC recommends amoxicillin at a dosage of 500 milligrams by mouth three times daily for 7 days.

Because amoxicillin isn’t one of the CDC-recommended treatments for gonorrhea or syphilis, there isn’t a standard dosage that’s prescribed. Suppose a doctor recommends amoxicillin treatment for your STD. In that case, the dosage will likely depend on your condition’s severity, age, medications being taken, and any medical conditions you have. 

As with all antibiotics, you must finish the entire course even if you start feeling better. Stopping the medication earlier than instructed can make your infection return or become harder to treat. 

RELATED: Amoxicillin dosage, forms, and strengths 

Risks and side effects of STD treatment with amoxicillin

Amoxicillin is generally well-tolerated; most people experience minimal side effects during treatment. However, all medications have their risks, and amoxicillin can cause mild to serious side effects. 

The most common side effects of amoxicillin may include:

• Rash
• Diarrhea
• Headache
• Nausea
• Vomiting
• Stomach pain
• Discoloration of the tongue
• Yeast infection

Rare but severe side effects of amoxicillin can include: 

• Clostridium difficile-associated diarrhea
• Liver problems
• Blood problems
• Seizures 
• Aseptic meningitis 
• Severe allergic reactions

Most amoxicillin side effects are temporary and will disappear once you finish treatment. However, certain side effects, such as blood problems or C. difficile diarrhea, can take longer to resolve. 

RELATED: Amoxicillin interactions to avoid

Amoxicillin resistance and STD treatment

Antibiotic resistance occurs when bacteria develop the ability to overcome the drug that is supposed to kill them. Bacterial growth can continue, making the infection more difficult and sometimes impossible to treat. 

As of late, antibiotic resistance in gonorrhea infections has become a public health concern. Gonorrhea has developed antibiotic resistance to almost all the antibiotics used for its treatment, and there are only a few antibiotics left that can successfully treat a gonorrhea infection. Antibiotic resistance in chlamydia and syphilis exists but is far less common.

Antibiotic resistance can be managed in the following ways: 

• STD prevention: Preventing STDs is a critical step in minimizing STD transmission. This can be done in several ways, including abstaining from sexual activity, vaccination, and mutual monogamy. 
• Get tested for STDs: Knowing the STD status of you and your sexual partner is one of the best ways to stop STDs from spreading. Many STDs can be cured with the proper treatment. 
• Finish the full course of treatment: If you’re receiving STD treatment, be sure to finish the entire course of treatment exactly as prescribed, even if you start to feel better.
• Openly communicate with your medical professionals: If you’re still having symptoms of an STD despite treatment, tell your healthcare provider. There is a chance your STD may have developed antibiotic resistance, and you may require alternative treatment. 
• Follow up with your healthcare professionals: In some cases, your healthcare professional may want to confirm that your STD has cleared after you finish treatment. For gonorrhea specifically, healthcare providers may recommend a follow-up test 7 to 14 days after completing treatment to ensure the infection is cleared.