Solosec (Secnidazole) – Oral

What Is Solosec?

Solosec (secnidazole) is a single-dose oral medication used to treat vaginal infections. It also treats a specific type of bacterial infection (trichomoniasis) passed through having sex. Secnidazole is a nitroimidazole antibiotic. It works by entering the bacterial cells and stopping their growth.

Solosec is available as a 2-gram single-dose oral packet and may contain polyethylene glycol.

Drug Facts

Generic Name: Secnidazole

Brand Name(s): Solosec

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Antibiotic

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Secnidazole

Dosage Form(s): Granule

What Is Solosec Used For?

Solosec (secnidazole) is used to treat vaginal infections (bacteria vaginosis) in people aged 12 years and older.

It also treats trichomoniasis, a sexually transmitted infection (STI). To lower the chance of reinfection, your healthcare provider may treat you and your partner with Solosec at the same time.

How to Take Solosec

Solosec is a single-dose treatment. It comes in a packet of oral granules To take it, sprinkle the entire contents of one packet onto yogurt, pudding, or applesauce and consume it within 30 minutes of preparation. To help with swallowing, you may drink some water after taking this medicine. However, do not mix it with any liquid as the granules will not dissolve. Also, do not chew the granules.

Avoid using products containing alcohol while on this drug and for two days after stopping it. Taking Solosec with alcohol may cause harmful reactions and side effects like nausea, throwing up, stomach pain, headache, and dizziness.


Store secnidazole at room temperature (68–77 degrees F) in a dry place. For short periods, you may store it between cool and mildly hot temperatures (59–86 degrees). Do not store it in your bathroom.

Keep all your medicines away from children and pets. Discard any unused and expired drugs. Ask your healthcare provider about the best ways to dispose of your medicine. Look for drug take-back programs in your area.

How Long Does Solosec Take to Work?

It takes about four hours for Solosec to peak in your system and the drug continues working in the body for several days after the dose.

What Are the Side Effects of Solosec?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at or 800-FDA-1088.

Common Side Effects

Solosec may cause little to no side effects in some people. Let your healthcare provider know immediately if your side effects do not go away or if they become bothersome. Common side effects include:

Severe Side Effects

Contact your healthcare provider immediately if you have any severe side effects. Call 911 if your symptoms appear to be life-threatening. Serious side effects of Solosec include vaginal discharge and allergic reactions, which can include signs such as a rash, wheezing, hives, swollen or peeling, or swelling of the face, tongue, mouth, lips, or throat.

Report Side Effects

Solosec may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Solosec Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (granules):
    • For vaginal infection caused by bacteria and trichomoniasis:
      • Adults and children 12 years of age and older—2 grams (1 packet) one time.
      • Children younger than 12 years of age—Use and dose must be determined by your doctor.


Secnidazole may lower the effect of sodium picosulfate, a type of stimulant laxative used to cleanse your bowel before a colonoscopy. Your healthcare provider may order a different bowel preparation drug if you are actively taking an antibiotic like secnidazole or be advised to take your secnidazole dose two hours before or six hours after bowel preparation.

Solosec may also lower the effect of the typhoid vaccine. Avoid getting a live vaccine while on this drug. You should delay vaccination until three days after stopping your antibiotics. Also, do not start antibiotics within three days of the last vaccine dose.

Do not breastfeed while using this medicine and for 96 hours after administration.

Missed Dose

Since only one dose is needed, take your missed dose as soon as you remember.

Overdose: What Happens If I Use Too Much Solosec?

Call your healthcare provider or the Poison Control Center immediately if you think someone else may have accidentally swallowed or overdosed on Solosec.

Call 911 immediately if someone collapses or isn't breathing after taking secnidazole.

What Happens If I Overdose on Solosec?

If you think you or someone else may have overdosed on Solosec, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Solosec, call 911 immediately.


Drug Content Provided by IBM Micromedex®

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

This medicine may cause a vaginal yeast infection. Check with your doctor right away if you have itching of the vagina or genitals or thick, white vaginal discharge with mild or no odor.

If you are taking this medicine for trichomoniasis, your doctor may want to treat your sexual partner at the same time you are being treated, even if he or she has no symptoms. Also, you should avoid having sexual intercourse until treated. These measures will help keep you from getting the infection back again from your partner. If you have any questions about this, talk with your doctor.

This medicine may increase your risk for cancer. Talk to your doctor about this risk.

What Are Reasons I Shouldn't Take Solosec?

Avoid this drug if you are hypersensitive to secnidazole, other nitroimidazole products, or any part of its formulation. This medication should also be avoided in people with Cockayne syndrome, a rare condition marked by irregular head size.

What Medications Interact With Solosec?

Taking Solosec with some drugs can lead to increased side effects associated with either drug. Do not take secnidazole with:

  • Alcohol 
  • Oral contraceptives, such as Loestrin (ethinyl estradiol and norethindrone)

Antibiotics may reduce how well the cholera vaccine works. Wait at least 14 days after stopping your antibiotic before getting the cholera vaccine. Tell your pharmacist or healthcare provider about all the medicines you take before getting a vaccine.

What Medications Are Similar?

Medications similar to Solosec that may be used to treat vaginal infections include:

This is a list of drugs also prescribed to treat vaginal infections. It is not a list of medicines recommended to take with Solosec. Do not take these drugs together unless your healthcare provider tells you to.

Frequently Asked Questions

  • What is Solosec used to treat?

    Solosec is used to treat vaginal infections in people 12 years and older. It also treats a specific type of bacterial infection (trichomoniasis) passed through having sex.

  • What is the common side effect of Solosec?

    Some common side effects include:

    • Nausea or vomiting
    • Stomach pain
    • Change in taste
    • Headache
    • Diarrhea
    • Vulvovaginal candidiasis
    • Vulvoaginal itchiness
  • Can I drink alcohol with Solosec?

    No. You should avoid drinking alcohol while on Solosec. Do not use it for at least two days after taking this medicine. You may get very sick if you take this medication with alcohol.

  • How long after mixing Solosec can I take it?

    Take the mixture within 30 minutes. Contact your healthcare provider for advice if it has been more than 30 minutes.

  • What should I do if I miss a dose of Solosec?

    Take your dose as soon as you remember. This is a one-time dose of medicine.

How Can I Stay Healthy While Taking Solosec?

While Solosec effectively treats vaginal infections, it may cause side effects like nausea, vomiting, or diarrhea. Using alcohol may worsen these side effects. Therefore, try to avoid drinking alcohol while on the Solosec and for at least two days after taking it.

If you are being treated for trichomoniasis, make sure that you get treated with your partner at the same time to avoid reinfection. Reach out to your healthcare provider if you have any questions or concerns.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Solosec label.

  2. Schwebke JR, Morgan FG Jr, Koltun W, Nyirjesy P. A phase-3, double-blind, placebo-controlled study of the effectiveness and safety of single oral doses of secnidazole 2 g for the treatment of women with bacterial vaginosis. Am J Obstet Gynecol. 2017;217(6):678.e1-678.e9. doi:10.1016/j.ajog.2017.08.017

  3. Muzny CA, Van Gerwen OT, Legendre D. Secnidazole: a treatment for trichomoniasis in adolescents and adults. Expert Rev Anti Infect Ther. 2022;20(8):1067-1076. doi:10.1080/14787210.2022.2080656.

  4. MedlinePlus. Cockayne syndrome.

  5. Food and Drug Administration. Vaxchora label.

By Queen Buyalos, PharmD
Queen Buyalos is a pharmacist and freelance medical writer. She takes pride in advocating for cancer prevention, overall health, and mental health education. Queen enjoys counseling and educating patients about drug therapy and translating complex ideas into simple language.