Treatment of trichomoniasis with drugs: metronidazole, tinidazole, secnidazole, schemes and errors

Trichomoniasis is a sexually transmitted infection caused by the protozoan parasite Trichomonas vaginalis. It is treated not with antifungal suppositories or random "broad-spectrum" antibiotics, but with medications specifically active against this pathogen. [1]

The main class of drugs used to treat trichomoniasis are nitroimidazoles. The US Centers for Disease Control and Prevention (CDC) states that nitroimidazoles are the only class of drugs with clinically proven efficacy against Trichomonas vaginalis. [2]

Nitroimidazoles include metronidazole, tinidazole, and secnidazole. Metronidazole remains the primary drug in many clinical guidelines, tinidazole is used as an alternative, and secnidazole has regulatory approval in the United States for the treatment of trichomoniasis in patients 12 years and older, but its position in international guidelines is not uniform. [3]

Treatment must be systemic, meaning the drug is taken orally. Topical forms of metronidazole, such as vaginal gel, are not considered a complete treatment for trichomoniasis because they do not achieve the required therapeutic levels in all areas of the genitourinary tract. [4]

The second essential part of treatment is simultaneous therapy of the sexual partner or partners. If only one person is treated, the infection often returns due to reinfection, even if the drug was chosen correctly. [5]

Treatment principle	What does this mean?
Confirmed infection must be treated.	It is advisable to confirm the diagnosis with a laboratory test.
The main drugs are nitroimidazoles	Metronidazole, tinidazole, secnidazole
Local remedies do not replace tablets	Oral therapy is needed
The partner is treated at the same time	This reduces the risk of re-infection.
Sex is temporarily excluded	Until all partners complete treatment
Recurring symptoms require evaluation of the cause.	Reinfection, missed tablets or resistance are possible

Source for the table: [6]

Metronidazole: the main drug for trichomoniasis

Metronidazole is the main drug used to treat trichomoniasis in women and men. It is a nitroimidazole and acts against Trichomonas vaginalis, not Candida, so it should not be used as a substitute for antifungal medications in cases of confirmed infection. [7]

For women, the U.S. Centers for Disease Control and Prevention recommends metronidazole 500 mg orally twice daily for 7 days. This regimen has become preferred because it has been shown to be more effective in women than a single 2-g dose. [8]

For men, the US Centers for Disease Control and Prevention (CDC) recommends metronidazole 2 g orally as a single dose as the standard regimen. This difference is due to the fact that there are fewer high-quality comparative studies of multi-day and single-dose regimens in men than in women. [9]

The World Health Organization's 2024 recommendations recommend metronidazole 400 mg or 500 mg orally twice daily for 7 days for adults and adolescents, including pregnant women and people with human immunodeficiency virus. Single-dose regimens are considered an option when there is serious concern that the patient will not be able to adhere to a multi-day course. [10]

It's important for patients to understand that the regimen depends on gender, pregnancy, concomitant infections, previous treatment, risk of reinfection, and local clinical guidelines. Therefore, the drug and dosage should be prescribed by a physician, not by a pharmacist "based on symptoms" or by the patient themselves. [11]

Patient or situation	Frequent metronidazole regimen	Important clarification
A woman without pregnancy	500 mg 2 times a day for 7 days	Preferred regimen according to the US Centers for Disease Control and Prevention
Man	2 g once	The Centers for Disease Control and Prevention's (CDC) master plan
Adults and adolescents according to the 2024 World Health Organization recommendations	400 mg or 500 mg 2 times a day for 7 days	A universal approach for many groups
A woman with human immunodeficiency virus	500 mg 2 times a day for 7 days	A single dose regimen is less preferable.
Re-infection	Depends on re-contact and previous pattern	Re-infection must be excluded.
Suspicion of stability	Specialized tactics	Self-increasing the dose is unacceptable.

Source for the table: [12]

Why do women often need a 7-day course?

A key change in recent years has been the transition to 7-day metronidazole in women. In a multicenter randomized trial, women who received metronidazole 500 mg twice daily for 7 days were less likely to remain positive for Trichomonas vaginalis on follow-up testing than women who received 2 g once. [13]

In this study, 11% of women in the 7-day regimen and 19% of women in the single-dose group tested positive after treatment. This means the multi-day regimen reduced the risk of persistent infection by approximately half. [14]

These data are particularly important because trichomoniasis in women is often combined with bacterial vaginosis and mucositis. A single high dose is more convenient, but convenience does not always mean better effectiveness. [15]

For women with human immunodeficiency virus (HIV), 7-day metronidazole is also preferred. The US Centers for Disease Control and Prevention (CDC) specifically recommends metronidazole 500 mg orally twice daily for 7 days, with retesting 3 months after treatment. [16]

Therefore, women should not replace the prescribed 7-day course with a single loading dose. This may increase the risk of continued infection, recurrence of symptoms, and further transmission to a partner. [17]

Why is a 7-day course important for women?	Practical significance
Lower risk of testing positive after treatment	Higher chance of cure
Better confirmed in clinical studies	Based on randomized data
Important for symptoms	Less risk of inflammation persisting
Important for human immunodeficiency virus	The one-shot scheme is less reliable
Requires discipline	You can't skip pills
Not replaceable with gel	The drug is needed orally.

Source for the table: [18]

Tinidazole: an alternative to metronidazole

Tinidazole is another drug from the nitroimidazole group used for trichomoniasis. The drug's labeling states that it is indicated for the treatment of trichomoniasis caused by Trichomonas vaginalis, and partners of infected patients should be treated concurrently to prevent reinfection.[19]

According to the Centers for Disease Control and Prevention (CDC), tinidazole 2 g orally once is an alternative regimen for both women and men. It may be useful in cases of metronidazole intolerance or in situations where the physician deems it more appropriate. [20]

Tinidazole has a longer half-life and achieves higher serum and genitourinary tract concentrations than metronidazole. The US Centers for Disease Control and Prevention also notes that it is generally associated with fewer gastrointestinal side effects.[21]

Clinical studies have shown high cure rates with tinidazole. Guidelines from the U.S. Centers for Disease Control and Prevention indicate that tinidazole regimens have been shown to be curative in approximately 92-100% of cases, but the choice of drug should still be tailored to the patient and the situation. [22]

During pregnancy, tinidazole is not generally chosen as a first-line drug because there is less safety data in humans than for metronidazole. The US Centers for Disease Control and Prevention recommends avoiding tinidazole during pregnancy. [23]

Characteristic	Metronidazole	Tinidazole
Class	Nitroimidazole	Nitroimidazole
The main role	First-line drug in many guidelines	Alternative
The Centers for Disease Control and Prevention (CDC) chart for women	500 mg 2 times a day for 7 days	2 g once as an alternative
The Centers for Disease Control and Prevention's (CDC) chart for men	2 g once	2 g once as an alternative
Tolerability	Nausea and a metallic taste are common.	Often better tolerated by the gastrointestinal tract
Pregnancy	Let's assume according to the readings	Usually avoided

Source for the table: [24]

Secnidazole: A new single-dose option, but not always a first-line standard

Secnidazole is a long-acting nitroimidazole approved in the United States for the treatment of trichomoniasis caused by Trichomonas vaginalis in patients 12 years of age and older. Solosec's official labeling states that partners of infected patients should be treated concurrently for trichomoniasis to prevent reinfection.[25]

The standard dosage form of secnidazole is granules for oral administration at a single dose of 2 g. This is convenient for patients who have difficulty adhering to a 7-day course, but ease of administration does not mean that the drug should automatically replace metronidazole in all guidelines and countries. [26]

A 2022 review describes secnidazole as a new drug approved by the US Food and Drug Administration for the treatment of trichomoniasis. The authors emphasize that it is a 5-nitroimidazole and is a potentially convenient single-dose option. [27]

However, the 2024 World Health Organization guidelines recommend metronidazole 400 mg or 500 mg twice daily for 7 days, rather than secnidazole. This means secnidazole should be considered in the context of availability, regulatory status, and local protocols. [28]

A patient should not switch from metronidazole to secnidazole on their own simply because a single dose seems more convenient. Gender, pregnancy, age, concomitant medications, risk of reinfection, and whether the partner is being treated simultaneously are important factors in making the right choice. [29]

Parameter	Secnidazole
Class	Nitroimidazole
Form	Granules for oral administration
Dose in the labeling	2 g once
US Age Labeling	12 years and older
Peculiarity	Convenient one-time scheme
Limitation	It is not a universal standard in all international guidelines.
An important rule	The partner is treated simultaneously

Source for the table: [30]

Medicines during pregnancy and breastfeeding

Trichomoniasis during pregnancy is clinically significant because it is associated with preterm labor, premature rupture of membranes, and low birth weight. Therefore, symptomatic pregnant women should be examined and treated rather than ignored. [31]

Metronidazole crosses the placenta, but available data indicate a low risk to the fetus. The U.S. Centers for Disease Control and Prevention reports that multiple studies have found no evidence of teratogenic or mutagenic effects with single- and multi-day regimens. [32]

In its 2024 recommendations, the World Health Organization includes pregnant women in the group of adults and adolescents for whom metronidazole 400 mg or 500 mg twice daily for 7 days is recommended. This makes 7-day metronidazole an important modern regimen for pregnancy as well, if a physician confirms the need for treatment. [33]

Tinidazole is generally avoided during pregnancy because human data are scarce and animal data are cautious. During breastfeeding, after a single 2 g dose of tinidazole, the US Centers for Disease Control and Prevention recommends discontinuing breastfeeding for 72 hours. [34]

Metronidazole is excreted in breast milk, but the infant receives a dose lower than the therapeutic dose used for infants. In some clinical situations, doctors advise interrupting breastfeeding for 12-24 hours after the maternal dose, especially with high-dose regimens. [35]

Situation	Drug tactics
Symptomatic pregnant woman	Examine and treat under the supervision of a physician
Metronidazole during pregnancy	Data indicate low risk to the fetus
Tinidazole during pregnancy	Usually avoided
Breastfeeding and metronidazole	Sometimes a 12-24 hour break is discussed
Breastfeeding and tinidazole	Pause 72 hours after a dose of 2 g
Partner of a pregnant woman	Must be treated simultaneously
Self-medication	Not recommended due to the risk of circuit error

Source for the table: [36]

Side effects and drug precautions

Metronidazole often causes an unpleasant metallic taste, nausea, abdominal discomfort, decreased appetite, headache, dry mouth, diarrhea, or constipation. These effects are generally not dangerous, but they can interfere with completing the course of treatment, so it's best for patients to know what to expect in advance. [37]

Less common but serious reactions to metronidazole include seizures, encephalopathy, aseptic meningitis, optic neuritis, and peripheral neuropathy with numbness or tingling of the extremities. If neurological symptoms occur, treatment should not be continued without medical evaluation.[38]

Tinidazole can also cause a metallic taste, nausea, vomiting, decreased appetite, abdominal pain or cramps, headache, weakness, and dizziness. Some patients tolerate it better, but this does not mean there is no risk. [39]

The issue of alcohol remains a practical concern. Metronidazole labeling states that oral metronidazole is associated with a disulfiram-like reaction to alcohol, including abdominal cramps, nausea, vomiting, headache, and flushing; therefore, many instructions advise avoiding alcohol during and for some time after treatment. [40]

However, modern reviews discuss the questionable evidence for a classic disulfiram-like reaction with metronidazole. In a practical article, it's safer for the patient to state: it's best to abstain from alcohol during the course of treatment and during the period specified in the instructions for a specific medication, as the risk of adverse reactions and administration errors is unjustified. [41]

Preparation	Common side effects	Important Warnings
Metronidazole	Nausea, metallic taste, abdominal pain, headache	Neurological reactions are rarely possible.
Tinidazole	Metallic taste, nausea, weakness, dizziness	Caution during pregnancy
Secnidazole	Gastrointestinal complaints, unpleasant taste, possible sensitivity reactions	Follow the instructions and treat partners simultaneously
Any nitroimidazole	Allergy possible	If you have a rash, swelling, or difficulty breathing, seek immediate medical attention.
Any drug	Interactions are possible	The doctor must know all the patient's medications.
Alcohol	Unpleasant reactions are possible	Best avoided during treatment and as directed

Source for the table: [42]

Partner treatment: without it, medications often "don't work"

With trichomoniasis, treating only a person who tests positive is not enough. The US Centers for Disease Control and Prevention emphasizes that simultaneous treatment of all current sexual partners is vital to prevent reinfection. [43]

A partner may be asymptomatic but still infected. This often leads to a mistaken situation: the patient completes the treatment, the symptoms disappear, then resumes sex with an untreated partner, and the infection returns. [44]

During treatment, sexual intercourse should be avoided until the patient and partners have completed treatment and symptoms have resolved. This rule applies to both vaginal sex and situations where there is a risk of contact with infected secretions. [45]

If there are multiple partners, the issue of notification and treatment should be discussed with a specialist. Some countries and regions have mechanisms for expedited treatment of partners, but legal regulations vary, so it is best to follow local medical recommendations. [46]

If trichomoniasis is confirmed, testing for other sexually transmitted infections is also recommended. The U.S. Centers for Disease Control and Prevention recommends testing for human immunodeficiency virus, syphilis, gonorrhea, and chlamydia. [47]

What should a partner do?	Why is this important?
Report a diagnosis	A partner can be infected without symptoms.
Get examined	Often infections are latent.
Get treatment	This prevents re-infection.
Do not have sex until treatment is completed.	Reduces the risk of transmission
Check for other infections	Trichomoniasis can be combined with other diseases.
Use condoms after treatment	Reduces the risk of new infections

Source for the table: [48]

Cure monitoring and re-analysis

In women, repeat testing is important after treatment, approximately 3 months later. The U.S. Centers for Disease Control and Prevention recommends repeat testing of all sexually active women after treatment for trichomoniasis due to the high risk of reinfection.[49]

Separate clinical literature clarifies that repeat testing helps identify both reinfection and persistent infection. In a 2024 study examining repeat testing, the authors noted that the US Centers for Disease Control and Prevention recommends universal repeat testing of women within 3 months of treatment. [50]

If symptoms persist or recur, molecular testing should not be performed too soon. The US Centers for Disease Control and Prevention advises that if symptoms persist or recur, nucleic acid amplification testing should not be performed until 3 weeks after completion of treatment to avoid detecting residual genetic material from the pathogen. [51]

For men, there is less evidence to support routine retesting. However, if symptoms persist, the partner tests positive again, or there was sexual contact with an untreated partner, the man should return to the doctor. [52]

It's important not to confuse cure monitoring with re-screening. Cure monitoring is needed when symptoms persist or the situation is complex, while re-testing after several months in women is aimed at identifying frequent reinfections. [53]

When to take the test	Who cares?	Comment
3 months after treatment	For sexually active women	Recommended due to the risk of re-infection
Not earlier than 3 weeks after the course if symptoms occur	Patients with suspected treatment failure	Otherwise, a false positive result is possible.
In case of repeated contact with an untreated partner	To everyone	Reinfection is possible
If symptoms persist	For women and men	An assessment of the cause is needed
Men without symptoms after treatment	Routine is not always required	The solution is individual
In women with human immunodeficiency virus	In 3 months	A sensitive test is desirable

Source for the table: [54]

What to do if trichomoniasis recurs

Recurrent trichomoniasis is more often associated not with a "weak drug," but with reinfection from an untreated partner, missed pills, or testing too early. Therefore, the doctor's first task is to determine whether there has been reexposure, that is, new contact with the source of infection. [55]

If a woman tests positive again after 7 days of metronidazole and has had contact with an untreated partner, the US Centers for Disease Control and Prevention recommends repeating the same 7-day course of metronidazole 500 mg twice daily.[56]

If there has been no recurrence, the woman is recommended to take metronidazole or tinidazole 2 g once a day for 7 days. This is a more intensive regimen that should not be initiated without a doctor's advice. [57]

If a man tests positive again after a single dose of 2 g metronidazole and has had contact with an untreated partner, a repeat single dose may be given. If there has been no re-exposure, metronidazole 500 mg twice daily for 7 days is recommended. [58]

In cases of persistent infection without reinfection and without treatment failure, resistance of Trichomonas vaginalis should be considered. The US Centers for Disease Control and Prevention performs susceptibility testing of Trichomonas vaginalis isolates to metronidazole and tinidazole for patients with treatment-resistant infections. [59]

Scenario	Probable cause	Tactics
The partner was not treated	Reinfection	Treat both at the same time
The patient missed pills	Insufficient therapy	Discuss a repeat course
The analysis was done earlier than 3 weeks	Residual genetic material	Repeat the test later
The woman tested positive again without repeated contact.	Possible treatment failure	High-dose regimen according to the doctor
The man tested positive again without repeated contact.	Possible treatment failure	7-day regimen according to the doctor
Several treatment failures	Possible stability	Specialized testing

Source for the table: [60]

Resistance to metronidazole and tinidazole

Drug resistance in Trichomonas vaginalis exists, but it does not affect the majority of patients. The US Centers for Disease Control and Prevention (CDC) estimates that metronidazole resistance occurs in approximately 4-10% of cases of vaginal trichomoniasis. [61]

Resistance to tinidazole is less common and has been less well studied. Guidelines from the US Centers for Disease Control and Prevention indicate that tinidazole resistance was detected in approximately 1% of infections in one study.[62]

A study by Schwebke et al. found that among 178 clinical isolates of Trichomonas vaginalis, metronidazole resistance was detected in 9.6% and tinidazole resistance in 0.56%. However, laboratory resistance does not always perfectly predict clinical response.[63]

Another study in 6 US cities found low-level metronidazole resistance in 4.3% of isolates and no moderate or high-level metronidazole resistance; all isolates in this study were susceptible to tinidazole.[64]

Practical conclusion: Resistance is possible, but before considering an infection resistant, reinfection, incorrect administration, vomiting after taking the pill, an early test, and an untreated partner must be ruled out. Only then should the doctor consider special regimens and susceptibility testing. [65]

Type of problem	How likely is it?	What is important
Reinfection	Often	Check your partner's treatment
Missed pills	Often	Specify reception by days
Too early test	Maybe	Do not test with nucleic acid amplification test before 3 weeks
Metronidazole resistance	Approximately 4-10% according to the CDC	Requires a specialist
Tinidazole resistance	Less often	Can be discussed in complex cases
True refractory infection	Less often	Culture and sensitivity are needed

Source for the table: [66]

Allergy to nitroimidazoles and complex cases

Allergy to nitroimidazoles is a complex situation because there are few effective alternatives. The US Centers for Disease Control and Prevention recommends that patients with an immunoglobulin E-mediated reaction to 5-nitroimidazoles should undergo desensitization to metronidazole according to published regimens in consultation with an allergist. [67]

Immunoglobulin E-mediated allergies typically present with urticaria, angioedema, bronchospasm, a drop in blood pressure, or anaphylaxis. In this situation, "just trying a small dose at home" is not an option, as the reaction could be dangerous. [68]

If it's not a true allergy, but rather nausea, a metallic taste, or abdominal discomfort, the approach is different. A doctor can explain how to take the drug, discuss tolerability, timing, and alternatives, but this doesn't mean a ban on the entire class of nitroimidazoles. [69]

Complex cases include pregnancy with recurrent infection, human immunodeficiency virus infection, suspected resistance, repeated treatment failures, allergy to nitroimidazoles, and persistent symptoms despite negative Trichomonas vaginalis tests. These situations require specialist attention, as a mistake can lead to unnecessary treatment and missed diagnoses. [70]

If nitroimidazoles are unavailable, evidence-based alternatives are few. Therefore, the primary goal is not to resort to folk remedies, but to accurately confirm the diagnosis, assess the allergy, rule out re-infection, and select a safe, specialized regimen. [71]

Situation	What to do
A real severe allergy	Allergist and desensitization
Just nausea or a metallic taste	Discuss tolerance, it's not always an allergy
Repeated treatment failures	Exclude reinfection and check for resistance
Pregnancy and relapse	Follow-up with a doctor
There are symptoms, the test is negative.	Look for other infections and causes
Homemade suppositories and antiseptics	Do not use as a substitute for treatment.

Source for the table: [72]

Common mistakes in drug treatment

The first mistake is treating without laboratory confirmation. Trichomoniasis symptoms are similar to those of bacterial vaginosis, candidiasis, gonorrhea, chlamydia, Mycoplasma genitalium, and other conditions, so incorrect self-diagnosis leads to inappropriate medication. [73]

The second mistake is using metronidazole vaginal gel instead of tablets. The US Centers for Disease Control and Prevention specifically states that metronidazole gel is not recommended for trichomoniasis because it is less effective than oral treatment. [74]

The third mistake is treating only one partner. Even the ideal drug will not protect against reinfection if the sexual partner remains infected and sex resumes too early. [75]

The fourth mistake is stopping the 7-day course once symptoms disappear. Symptoms may resolve before the infection is completely cleared, so the course must be completed as prescribed. [76]

The fifth mistake is performing a follow-up molecular test several days after treatment. This test can detect residual genetic material from the pathogen, so it is not performed for re-evaluation until three weeks after completion of therapy. [77]

Error	Consequence	What is the correct way?
Treatment without analysis	Another infection may be missed.	First, diagnostics
Only candles or gel	The infection may persist	Oral medication
The partner is not receiving treatment	Reinfection	Treat simultaneously
Skipping pills	Lower efficiency	Complete the course
Sex until the end of treatment	Risk of transmission	Temporary sexual pause
Early control test	Risk of false positive result	Wait for the right time

Source for the table: [78]

FAQ

What medications treat trichomoniasis? The main drugs are metronidazole and tinidazole, and secnidazole is also approved in the US for patients 12 years and older; all of these are nitroimidazoles. [79]

Why can't trichomoniasis be treated with suppositories? Topical forms don't provide sufficient coverage in all areas of the genitourinary tract, so oral medications are needed for trichomoniasis. [80]

What is the best metronidazole regimen for women? Current recommendations from the US Centers for Disease Control and Prevention for women recommend metronidazole 500 mg twice daily for 7 days. [81]

What regimen is used for men? According to the recommendations of the US Centers for Disease Control and Prevention, the main regimen for men remains metronidazole 2 g orally once, and tinidazole 2 g once is an alternative. [82]

Why does the World Health Organization recommend 7-day metronidazole? In its 2024 guidelines, the World Health Organization recommends metronidazole 400 mg or 500 mg twice daily for 7 days for adults and adolescents, including pregnant women and people with human immunodeficiency virus. [83]

Can secnidazole be used for treatment with a single dose? In the United States, secnidazole 2 g is approved for the treatment of trichomoniasis in patients 12 years of age and older, but its use must comply with local guidelines and a physician's prescription. [84]

Should the partner be treated? Yes, partners are treated simultaneously, as otherwise reinfection is possible, that is, re-infection after a successful course. [85]

When can sex resume? Sex is resumed only after the patient and all partners have completed treatment and after symptoms have disappeared. [86]

Can you drink alcohol with metronidazole? It's generally best to avoid alcohol during treatment and for the period specified in the instructions for a particular medication, as the instructions warn of possible adverse reactions. [87]

What should you do if treatment doesn't work? It's important to check your partner's treatment, whether it's being taken correctly, when to retest, and whether resistance is likely; a repeat regimen should be prescribed by a doctor. [88]

Key points from experts

Kimberly A. Workowski, MD, is the lead author of the Centers for Disease Control and Prevention guidelines for the treatment of sexually transmitted infections. The key message of the guidelines: metronidazole 500 mg twice daily for 7 days is the standard regimen for women, metronidazole 2 g once daily remains the standard regimen for men, and treatment of partners is essential to prevent reinfection. [89]

Patricia J. Kissinger, PhD, MPH, is a Trichomonas vaginalis researcher. Her randomized trial showed that in women, 7 days of metronidazole reduced the proportion of positive control tests compared with a single 2-g dose.[90]

Jackie Sherrard, MD, is the lead author of the British Association for Sexual Health and HIV guidelines on Trichomonas vaginalis. The British guidelines support multi-day regimens of metronidazole and emphasize the need for treatment of sexual partners, sexual abstinence, and accurate diagnosis. [91]

The World Health Organization Guidelines Development Group on Sexually Transmitted Infections (WHO Sexually Transmitted Infections) recommends metronidazole 400 mg or 500 mg twice daily for 7 days for adults and adolescents with Trichomonas vaginalis, including pregnant women and people with human immunodeficiency virus infection, in their 2024 recommendations. [92]

Charlotte A. Muzny, MD, MPH, authored a review of secnidazole for trichomoniasis. Her review describes secnidazole as a new single-dose 5-nitroimidazole approved in the US for the treatment of trichomoniasis, which is important for patients who have difficulty complying with multi-day regimens.[93]

US Centers for Disease Control and Prevention, Division of Parasitic Diseases and Malaria. The division's practice statement: In refractory infections, specialized susceptibility testing of Trichomonas vaginalis to metronidazole and tinidazole is feasible, which helps guide management when resistance is suspected. [94]

Result

Medical treatment for trichomoniasis focuses on nitroimidazole drugs: metronidazole, tinidazole, and, in some countries, secnidazole. It is not an infection that can be reliably cured with suppositories, douches, antiseptics, probiotics, or antifungal medications. [95]

For women, the most proven current regimen remains metronidazole 500 mg twice daily for 7 days, as it is more effective than a single dose in reducing the risk of persistent infection. For men, the US Centers for Disease Control and Prevention recommends metronidazole 2 g once daily as the primary regimen. [96]

Partners should be treated simultaneously, and sex should be avoided until all participants have completed treatment and symptoms have resolved. Without this, even the right medication may fail due to reinfection. [97]

If symptoms persist or the test is positive again, do not repeat the pills yourself. First, evaluate the partner's treatment, missed doses, or early testing, and only then consider resistance to metronidazole or tinidazole and specialized regimens. [98]