Gynastin

This combination vaginal tablet (metronidazole, neomycin sulphate, polymyxin B, and nystatin) is indicated for the treatment of mixed vaginal infections (fungal and/or bacterial), including:

• Bacterial vaginitis due to common pyogenic (pus-forming) organisms
• Vaginitis due to Trichomonas vaginalis and Gardnerella vaginalis
• Fungal (monilial) vaginitis due to Candida albicans
• Mixed vaginitis due to a combination of Trichomonas and yeast, or other combined bacterial/fungal pathogens

Contains metronidazole, neomycin sulphate, polymyxin B, and nystatin as active ingredients, formulated as a vaginal tablet or suppository for intravaginal use. Confirm the exact strength of each component on the specific product's own label.

This is a four-ingredient combination vaginal tablet designed to treat mixed vaginal infections in a single product, since vaginitis in clinical practice is often caused by more than one type of organism at once - bacteria, protozoa (Trichomonas), and fungi (Candida) - making single-agent treatments potentially inadequate. Metronidazole targets anaerobic bacteria and Trichomonas; neomycin, an aminoglycoside, and polymyxin B together cover a broad range of gram-positive and gram-negative bacteria, including Pseudomonas; and nystatin, an antifungal, targets Candida and other yeasts. This broad combined coverage makes it a practical first-line option when the exact cause of vaginal symptoms is uncertain or mixed.

Therapeutic Class: Vaginal Antimicrobial Combination (Antibacterial + Antiprotozoal + Antifungal)

This combination acts locally within the vagina after insertion, with each component targeting a different class of organism: metronidazole against anaerobic bacteria and Trichomonas vaginalis, neomycin (bactericidal, active against some gram-positive and many gram-negative organisms) and polymyxin B (active against gram-negative organisms including Pseudomonas aeruginosa) together against a broad range of bacteria, and nystatin against Candida albicans and other yeasts by binding to sterols in the fungal cell membrane and disrupting its integrity. Systemic absorption from vaginal use is generally limited compared to oral or injectable administration of these same components, though it is not negligible, particularly with prolonged use or if the vaginal mucosa is inflamed.

• Wash hands before and after use
• Insert the tablet high into the vagina at bedtime, using the applicator provided if supplied, following the manufacturer's specific instructions
• Complete the full prescribed course, even if symptoms improve before the course is finished, to fully clear the infection
• Avoid sexual intercourse during treatment, or use a barrier method, since the product may weaken latex condoms or diaphragms
• Some products recommend avoiding tampon use during treatment; follow the specific product's instructions
• Treatment of the sexual partner may be recommended for certain infections (such as Trichomonas), per your doctor's advice, to reduce the risk of reinfection

Given the predominantly local (vaginal) action of this combination, significant systemic drug interactions are less likely than with oral or injectable use of these components, but the following should still be considered:

• Alcohol: the metronidazole component can cause a disulfiram-like reaction (flushing, nausea, palpitations) if combined with alcohol; avoid alcohol during treatment and for a short period afterward, as advised for oral metronidazole use.
• Warfarin and other anticoagulants: metronidazole, even via the vaginal route, may enhance anticoagulant effect in some patients with sufficient systemic absorption; monitor if combined, particularly with prolonged use.
• Other vaginal products used at the same time: avoid combining with other vaginal medicines unless specifically directed by your doctor, since this can alter absorption or increase local irritation.

Common side effects

• Local burning, itching, or irritation at the application site
• Increased vaginal discharge

Less common effects

• Allergic contact dermatitis or sensitization, particularly with the neomycin component, which is a recognized contact allergen
• Vaginal dryness or discomfort

Serious effects (seek medical attention)

• Signs of a severe allergic reaction: widespread rash, swelling, difficulty breathing
• Symptoms that worsen instead of improving, or that persist beyond the treatment course, which should be reassessed by a doctor rather than continuing self-treatment

Pregnancy

Vaginal metronidazole-containing combinations have been used during pregnancy for specific vaginal infections when clinically indicated, given generally lower systemic absorption than oral metronidazole; use during pregnancy should be discussed with your doctor, particularly regarding the specific trimester and clinical situation.

Breastfeeding

Given the local nature of vaginal administration, systemic absorption and transfer into breast milk are expected to be limited compared to oral use, but use during breastfeeding should still be discussed with a healthcare professional.

• Complete the full course as prescribed, even if symptoms improve early, to fully clear the infection and reduce the risk of recurrence.
• Avoid alcohol during treatment and for a short period afterward, given the metronidazole component's potential to cause a disulfiram-like reaction.
• The neomycin component can cause allergic sensitization in some patients; discontinue and consult a doctor if increasing local irritation or an allergic-type reaction develops.
• This product may weaken latex condoms or diaphragms; use an alternative barrier method or avoid intercourse during treatment.
• If symptoms persist or worsen despite treatment, seek medical reassessment, since an alternative diagnosis or resistant organism may need to be considered.

Overdose in the conventional sense is unlikely with normal vaginal use, given limited systemic absorption; excessive or more frequent use than directed does not improve effectiveness and may increase local irritation. If a tablet is accidentally swallowed, contact a doctor or pharmacist for advice, particularly given the metronidazole and neomycin content.

Store at room temperature, away from moisture and heat, as directed on the specific product's label. Keep out of reach of children.

• Pregnancy: Use should be guided by a doctor, taking into account the specific trimester and clinical situation.
• Patients with known neomycin sensitivity: Neomycin is a well-recognized cause of allergic contact dermatitis; patients with a known reaction to topical neomycin-containing products should discuss alternatives with their doctor.
• Sexual partners: Partner treatment may be advised for specific infections such as trichomoniasis, to reduce reinfection risk, per your doctor's guidance.

Treatment is typically a 12-day course, with one tablet inserted vaginally each night at bedtime, or as otherwise directed by the treating physician based on the specific infection and clinical response. The full course should be completed even if symptoms improve earlier.

Drug Class: Nitroimidazole (metronidazole) + aminoglycoside (neomycin) + polypeptide antibiotic (polymyxin B) + polyene antifungal (nystatin)

Metronidazole is converted within susceptible anaerobic bacteria and protozoa (such as Trichomonas) into reactive compounds that damage the organism's DNA, killing it. Neomycin and polymyxin B both disrupt bacterial cell function - neomycin by interfering with bacterial protein synthesis, and polymyxin B by disrupting the integrity of the bacterial cell membrane, particularly in gram-negative organisms. Nystatin binds to sterols (such as ergosterol) in the fungal cell membrane, creating pores that cause the fungal cell's contents to leak out, killing the fungus. Together, this combination targets the anaerobic bacterial, protozoal, gram-negative bacterial, and fungal organisms most commonly responsible for mixed vaginal infections.

This combination is intended for adult vaginal use; it is not indicated for use in children, and any concerns about vaginal symptoms in a child or adolescent should be evaluated by a doctor rather than self-treated with this product.