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By: RSC Editorial Team

July 3, 2023

How Long Does It Take for Penicillin To Cure Syphilis?

Untreated syphilis can cause critical damage to your blood vessels, brain, heart, and nervous system, potentially causing irreversible paralysis, organ damage, blindness, and more. Luckily, the early stages of the infection are easily curable and treatable with penicillin G benzathine, an antibiotic. So, how long does it take for penicillin to cure syphilis? 

Syphilis treatment spans depend on the infection’s stage of development. Early diagnosis and treatment are key for successfully using penicillin for syphilis treatment. Below, the Rapid STD Testing team discusses all the STI treatment guidelines you should know regarding syphilis. 

Living With Syphilis

Syphilis is a sexually transmitted infection caused by the Treponema pallidum bacterium. The infection has four stages, each categorized by unusual symptoms that can easily go undetected. Understanding common syphilis symptoms and signs can help you detect an infection during the early stages while it’s still easily treatable. 

Syphilis stages include the following:

  • Primary: Primary syphilis typically appears a few weeks after the infection and is curable with penicillin. You can only contract syphilis through direct skin contact (typically through sex) with open sores. Primary syphilis causes a round sore around the genitals, mouth, or rectum. 
  • Secondary: Secondary syphilis, also known as the “great imitator,” appears a bit later, mimicking symptoms of common conditions. You may experience rashes, fever, fatigue, hair loss, headaches, swollen lymph nodes, and more. Secondary syphilis is still curable with penicillin. 
  • Latent: Latent syphilis causes no symptoms and occurs as the bacteria progress into the final stage. In many cases, you may be able to treat early latent syphilis with penicillin. The late latent syphilis stage begins 12 months after infection and can last years. 
  • Tertiary: Tertiary syphilis typically doesn’t occur until many years after the infection if you didn’t receive treatment. This life-threatening stage can cause heart disease, blindness, memory loss, neurological disorders, hearing loss, bone destruction, and more. You cannot cure tertiary syphilis. 

Now that you understand what syphilis is and how the infection progresses, let’s discuss what you can do if you notice symptoms. First, order a rapid STD test from Rapid STD Testing or visit a local clinic to determine whether you have syphilis. 

If your test comes back positive, don’t panic. Over 133,000 new cases of syphilis popped up in 2020 alone. Living with syphilis is extremely manageable. 

To start, speak with your doctor about scheduling your penicillin injection. Penicillin can only cure the primary, secondary, and early latent stages of syphilis, so you don’t want to delay this treatment. 

You should inform any sexual partners so they can get tested as well. Refrain from sex after syphilis treatment for at least 14 days to ensure you’re no longer contagious. 

How Is Syphilis Treated?

So, how do doctors treat syphilis, how many shots of penicillin does it take to cure syphilis, and how long does it take for penicillin to cure syphilis?

Doctors almost always recommend treating syphilis with a one-time injection of penicillin G benzathine. This antibiotic combines two penicillin G molecules. Patients in the primary and secondary stages of syphilis typically only need one injection. However, you may require multiple doses if you’ve had the infection for over a year. 

Some doctors estimate that penicillin can take around 14 days to cure syphilis, allowing you to heal fully. However, it depends on the stage of your infection and other factors. Your doctor will likely recommend a follow-up blood test to ensure a total cure following the penicillin injection. The timing of your follow-up test will depend on the stage of your infection. 

If you have a penicillin allergy, you may still be eligible for treatment, as your doctor can administer a desensitization process that allows your body to handle the medication. Pregnant women may also take penicillin, and many doctors advocate for it. Syphilis can harm the unborn child, causing birth defects, cataracts, deafness, seizures, stillbirths, and more, so prompt penicillin treatment is critical in protecting mother and baby. 

Penicillin injections typically cause temporary side effects known as the Jarisch-Herxheimer reaction that can last around 24 hours. You may experience the following symptoms:

  • Fever
  • Joint or muscle pain
  • Headaches
  • Nausea
  • Chills

You should not use these symptoms as a basis for your syphilis recovery. Such effects occur with many antibiotic injections and do not signify a worsening of your infection. After receiving your penicillin shot, you should follow all medication protocols provided by your doctor, fulfill your follow-up testing visit, monitor your symptoms, and abstain from sex until you’re 100% cured. 

Moving forward, you may want to receive an HIV test, as syphilis infections can increase your chances of contracting HIV. You can inform your partner of their syphilis risk so they can also get tested. After being cured of syphilis, continue practicing safe sex and receiving regular same-day STD testing to stay ahead of your health. 

Antibiotic Resistance

Antibiotic resistance occurs when bacterial infections and their treatments become so prevalent and widely available that the bacteria begin evolving to become resistant to antibiotics. The growing threat of antibiotic-resistant STIs remains a concern for syphilis, gonorrhea, and chlamydia patients, given the extreme prevalence of these diseases. 

The syphilis bacteria, in particular, may resist antibiotic treatments in pill form yet successfully respond to a penicillin G benzathine injection, making it the primary treatment method. Unfortunately, the injection isn’t widely available, particularly in countries with high syphilis burdens. 

Complications From Untreated Syphilis

Untreated syphilis will eventually develop into the tertiary stage, causing severe, irreparable damage to major bodily functions and organs. As a result, complications can include blindness, hearing loss, heart disease, memory loss, neurological disorders, tissue and bone destruction, and more.  

Syphilis Reinfection

Now that you know the answer to “How long does it take for penicillin to cure syphilis?” let’s talk about what comes next. Penicillin does not prevent syphilis reinfection, so you should continue practicing safe sex moving forward. Having syphilis in the past does not allow you to build a tolerance to it, so you’re just as susceptible to getting it again as you were before. 

Reinfection rates for syphilis are high because the infection is so prevalent. High-risk populations must be especially aware. You may be at high risk of contracting syphilis if you have unprotected sex, are HIV positive, or are a man having sex with other men. 

Some research shows that men having sex with men experience syphilis reinfection rates as high as 5.9 to 22%, whereas Americans with HIV face 9% to 22% risks of treatment failure or reinfection (respectively) when both partners have HIV. 

Preventing syphilis reinfection begins with understanding why the infection occurs. Syphilis transmits via skin-to-skin contact as the bacteria enter the mouth, anus, or genital region through oral or sexual intercourse. If you have sex with a partner who has an open syphilis sore, the bacteria can enter your system, causing you to form a sore that will spread the bacteria into your bloodstream, allowing secondary syphilis to develop. 

You can prevent syphilis reinfection by practicing the following safe-sex guidelines:

  • Reduce your number of sexual partners
  • Use barrier methods during sex, like condoms
  • Avoid engaging in sexual activity if you or your partner(s) have open wounds
  • Maintain open communication with your sexual partner(s)
  • Learn about the symptoms of syphilis so you know what to look for
  • Educate sexual partner(s) on syphilis symptoms
  • Get tested regularly for all STDs
  • Urge your sexual partner(s) to get tested regularly as well

If you’re sexually active, you can get syphilis. You may be at a higher risk if you have (or have had, in the case of something curable) other STIs, like chlamydia, herpes, HIV, or gonorrhea. Be sure to follow our guidelines above and get tested regularly to reduce your risks. 

At Rapid STD Testing, we offer a 10-panel STD test to make the process easy. You can book the panel online for a full, comprehensive screening, then complete the blood screening, plasma sample, or urine sample at a laboratory near you. We offer affordable prices and easy access to testing so you and your partners can prioritize your health. 

Stop the Spread and Get Tested Today

Syphilis can become a life-threatening, irreversible infection if you don’t seek treatment in its early stages. Now that you know the answers to common questions like “Is there a cure for syphilis?” and “How long does it take for penicillin to cure syphilis?” you can get tested to begin prioritizing your health today.

Syphilis is a highly prevalent STI, though you can do your part to prevent the spread by receiving regular testing and treatment. Order STD tests from Rapid STD Testing, visit a local screening center, or call us at (866) 872-1888 with any questions.


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By: RSC Editorial Team
July 3, 2023

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