Healthcare provider explaining metronidazole for trich to patient in office

Metronidazole for Trich: Key Points to Know

Written on July 29, 2023 by Sendra Yang, PharmD, MBA. 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.

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Dozens of sexually transmitted diseases (STDs) infect millions of people every year.[1] There were 26 million new sexually transmitted infections (STI), and one in five people in the United States had an STI in 2018.[2] In 2020, the World Health Organization (WHO) estimated there were 374 million new STIs worldwide.[3] If you are one of the millions with an STD, know that there are treatment options for all, and many are curable.[1] One of the many STDs that has a cure is trichomoniasis, also known as trich.[4] Read on to learn more about taking metronidazole for trich.

What Is Trichomoniasis?

Trichomoniasis is the most prevalent nonviral STI worldwide.[4,6] Global estimates of trichomoniasis infections were approximately 156 million in 2020.[3] In the U.S., the CDC reported that over two million Americans were infected with trich in 2018.[5]

Trichomoniasis is caused by a protozoan parasite called Trichomonas vaginalis (T. vaginalis).[5,6] Trichomoniasis is transmitted through sexual contact with someone who was infected with the parasite.[4-6] T. vaginalis is a motile protozoan organism that can reside in the cavity of the urogenital tract.[6] The protozoan releases proteins that are toxic to the cells lining the area.

Up to 70% of people with trich infection experience no symptoms.[5] When symptoms occur, they can range from mild irritation to severe inflammation. During a trich infection, the vaginal pH is typically raised in women.[6] Additionally, women often present with yellow or green vaginal discharge and a foul odor, increased urinary frequency, dysuria, and vulvar pruritus or redness.[5,6] In men, trichomoniasis frequently has no symptoms, but if there are symptoms, urethritis is the most common, and prostatitis and epididymitis could also occur.[5,6]

A trichomoniasis diagnosis cannot be made based on only your symptoms.[5] Your healthcare provider will typically conduct a physical exam and order laboratory testing to assist with a diagnosis.[4-6] Nowadays, there is also an option for at-home lab testing for trichomoniasis. The at-home lab testing allows you to collect your sample in the comfort of your own home and receive your results digitally.

Metronidazole for Trich

Once you are diagnosed with trich, your healthcare provider will prescribe you treatment. The recommended treatment for women and men is metronidazole, based on the CDC STI treatment guidelines.[4] The recommended dosing for women is 500 mg of metronidazole, taken orally two times per day for seven days. The recommended dosing for men is 2 g of metronidazole orally as a single dose. Metronidazole for trich makes trichomoniasis the most common curable STD.[5]

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What Is Metronidazole?

Metronidazole is a prescription medication that belongs to a class of drugs known as nitroimidazole antibiotics.[7,8] It treats protozoal and specific bacterial infections.[7,8] It is approved by the United States Food and Drug Administration for the treatment of T. vaginalis. Metronidazole is also used to treat skin or heart bacterial infections and intestinal parasitic infections.[7,8] The exact mechanism of how metronidazole works is not known.[8] However, metronidazole is thought to work by interacting with DNA to cause the death of the organisms.[7,8]

The common adverse effects of metronidazole include confusion, peripheral neuropathy, metallic taste, nausea, vomiting, and diarrhea.[7,8] Other adverse effects are headache, genital pruritus, abdominal pain, dizziness, dry mouth, and dysmenorrhea. Metronidazole should not be used if you have a hypersensitivity to the drug or any of its components and should also be avoided in the first trimester of pregnancy.[7] Consuming alcohol or products containing propylene glycol should be avoided for three days after completing therapy, and avoid disulfiram use for two weeks.[7]

Tips for Taking Metronidazole for Trichomoniasis

If you are diagnosed with trichomoniasis and your healthcare provider prescribes you metronidazole, here are a few pointers to consider [4,5,7]:

  • Abstain from alcohol use with metronidazole to avoid severe side effects such as abdominal pain, nausea, vomiting, headaches, and flushing
  • Take with food if metronidazole upsets your stomach
  • After completing metronidazole therapy for trich, you can still get reinfected
  • Make sure that you and your sexual partner both get tested and complete metronidazole treatment to reduce reinfection risk

Next Steps With Everlywell

Via Everlywell, you have the option of on-demand online STD treatment through a certified clinician. If you think you may have been exposed to a sexually transmitted infection or disease, you can connect and speak with a healthcare provider within 2 hours. The visit will include a discrete video call where you can discuss your sexual health concerns and get answers to questions you may have. During the appointment, the clinician will provide you with personalized recommendations and next steps based on the symptoms you are experiencing and your exposure history.

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  1. CDC - STD Diseases & Related Conditions. Centers for Disease Control and Prevention. Last reviewed July 7, 2023. Accessed July 17, 2023.
  2. STI prevalence, incidence, and cost estimates. Centers for Disease Control and Prevention. Last reviewed February 18, 2021. Accessed July 17, 2023.
  3. Sexually transmitted infections (STIs). World Health Organization. Accessed July 17, 2023.
  4. Trichomoniasis - STI treatment guidelines. Centers for Disease Control and Prevention. Last reviewed September 21, 2022. Accessed July 17, 2023.
  5. STD Facts - Trichomoniasis. Centers for Disease Control and Prevention. Last reviewed April 25, 2022. Accessed July 17, 2023.
  6. Schumann JA, Plasner S. Trichomoniasis. [Updated 2022 Jun 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023.
  7. Weir CB, Le JK. Metronidazole. [Updated 2023 Feb 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023.
  8. DailyMed - metronidazole tablet. U.S. National Library of Medicine. Accessed July 17, 2023.
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