Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
EXSEL vs GYNIX
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Exsel (selenium sulfide) is an antifungal agent that reduces the production of cutaneous oils and exerts cytostatic effects on epidermal cells. It inhibits the growth of Pityrosporum ovale and other fungi by interfering with oxidative enzyme systems, leading to decreased sebum production and normalization of epidermal turnover.
Coagulative necrosis of tissue via trichloroacetic acid; chemical cauterization of epithelial cells.
Treatment of tinea versicolor (pityriasis versicolor),Management of dandruff and seborrheic dermatitis of the scalp
Cervical inflammation,Vaginal infections,Treatment of genital warts,Chemical cautery of skin lesions
1-2 mg orally once daily; maximum dose 2 mg/day.
1 vaginal tablet (100 mg) once daily at bedtime for 7 days
Terminal half-life: 12-18 hours (mean 15 h); requires dose adjustment in renal impairment (Cr Cl <30 m L/min).
Terminal half-life is 2.5-3 hours in patients with normal renal function; prolonged to 6-8 hours in moderate renal impairment (Cr Cl 30-50 m L/min) and up to 12-15 hours in severe renal impairment (Cr Cl <30 m L/min).
Minimal systemic absorption after topical application; any absorbed selenium is primarily excreted in urine, with minor metabolism via reduction to selenides and methylation to dimethylselenide.
Not metabolized; acts locally via direct chemical action.
Renal: ~70% unchanged; biliary/fecal: ~30% as metabolites.
Primarily renal (approximately 60-80% as unchanged drug) and biliary (20-30% as metabolites; unchanged drug not detected in bile). Fecal elimination accounts for <5%.
95% bound to albumin and alpha-1-acid glycoprotein.
Approximately 20-30% bound to albumin with negligible binding to alpha-1-acid glycoprotein.
0.8-1.2 L/kg; indicates extensive extravascular distribution.
Apparent Vd is 0.8-1.1 L/kg (range 0.6-1.3 L/kg), indicating extensive tissue distribution (e.g., lung, liver, bone).
Oral: 60-80%; first-pass metabolism reduces bioavailability by 20-40%.
Oral: 85-95% (immediate-release) and 70-80% (sustained-release due to first-pass effect). Vaginal: 5-10% (minimal systemic absorption). IV: 100%.
No adjustment required for mild to moderate impairment. Severe impairment (GFR <30 m L/min): contraindicated.
No dose adjustment required for GFR ≥30 m L/min. For GFR <30 m L/min: use with caution, consider alternative therapy.
Child-Pugh A: no adjustment. Child-Pugh B or C: contraindicated.
Mild to moderate hepatic impairment (Child-Pugh A or B): no adjustment. Severe (Child-Pugh C): contraindicated.
Not recommended for use in pediatric patients due to lack of safety and efficacy data.
Not approved for use in pediatric patients.
Start at 1 mg orally once daily; titrate cautiously due to increased risk of falls and hypotension.
No dose adjustment required; use same as adult dosing.
None.
None.
Avoid contact with eyes, eyelids, and mucous membranes. If contact occurs, rinse thoroughly with water. Discontinue if local irritation or sensitization develops. Use with caution in patients with inflamed or broken skin due to increased absorption risk. Not for use on large areas of the body for prolonged periods.
Avoid contact with normal tissue; risk of chemical burns; not for use on neoplastic lesions.
Hypersensitivity to selenium sulfide or any component of the formulation. Do not use on broken or inflamed skin.
Hypersensitivity to trichloroacetic acid; pregnancy (relative); use on malignant tissue.
No known food interactions.
No known food interactions with topical use. However, avoid concurrent use of iodine-containing supplements or medications, as it may increase systemic iodine load.
Pregnancy Category D. First trimester: Associated with Ebstein's anomaly and other congenital heart defects; avoid if possible. Second and third trimesters: Risk of fetal hyperthyroidism or hypothyroidism, cranial synostosis, intellectual disability, and neonatal goiter if maternal hyperthyroidism is treated with this drug. Use only if clearly needed and maternal benefit outweighs fetal risk.
First trimester: Inadequate human data; animal studies not available. Theoretical risk based on pharmacologic action. Second and third trimesters: No known fetal harm from topical use. Systemic absorption minimal.
Excreted in human milk. M/P ratio not available. Potential for serious adverse reactions in nursing infants, including thyroid dysfunction and arrhythmias. Decision to discontinue nursing or drug based on importance of drug to mother.
No data on excretion in human milk. Expected minimal systemic absorption. Use caution if applied to breast area. M/P ratio unknown.
Pregnancy may increase clearance of this drug; dose adjustments often not required, but individualize based on maternal thyroid function and clinical response. Lower doses may be needed to avoid fetal hypothyroidism.
No dose adjustment necessary for topical use. Systemic absorption negligible.
EXSEL (selenium disulfide) 2.5% shampoo: Use twice weekly for 2 weeks, then once weekly for maintenance. Limit application to 5-10 minutes before rinsing. Avoid contact with eyes or broken skin. Can cause temporary hair discoloration (especially on bleached or permed hair). May stain jewelry and clothing. For dandruff and seborrheic dermatitis of the scalp.
GYNIX (povidone-iodine) is a topical antiseptic. Avoid use in patients with iodine hypersensitivity or thyroid disorders (e.g., Hashimoto's thyroiditis). Prolonged use on large wounds may cause iodine absorption and thyroid dysfunction. Monitor for local irritation or allergic contact dermatitis.
Shake bottle well before use.,Wet hair thoroughly before applying shampoo.,Apply enough shampoo to lather and massage into scalp for 2-3 minutes.,Leave on scalp for 5 minutes (up to 10 minutes) before rinsing thoroughly.,Rinse hair and scalp completely to avoid residue.,Use twice weekly for first 2 weeks, then once weekly as directed.,Avoid contact with eyes; if contact occurs, rinse thoroughly with water.,Do not use on broken or irritated skin.,Discontinue use and consult doctor if rash or irritation develops.,May stain clothing and jewelry; rinse thoroughly after use.
Do not use if you are allergic to iodine or have a thyroid condition.,For external use only. Avoid contact with eyes, mouth, or open wounds unless directed.,Discontinue and inform your doctor if you develop rash, itching, or swelling.,Store at room temperature away from light. Do not freeze or heat.,Not for use on deep or puncture wounds, or severe burns without medical advice.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about EXSEL vs GYNIX, answered by our medical review team.
EXSEL is a Topical Antifungal that works by Exsel (selenium sulfide) is an antifungal agent that reduces the production of cutaneous oils and exerts cytostatic effects on epidermal cells. It inhibits the growth of Pityrosporum ovale and other fungi by interfering with oxidative enzyme systems, leading to decreased sebum production and normalization of epidermal turnover.. GYNIX is a Polyene Antifungal that works by Coagulative necrosis of tissue via trichloroacetic acid; chemical cauterization of epithelial cells.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between EXSEL and GYNIX depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of EXSEL is: 1-2 mg orally once daily; maximum dose 2 mg/day.. The standard adult dose of GYNIX is: 1 vaginal tablet (100 mg) once daily at bedtime for 7 days. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between EXSEL and GYNIX in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. EXSEL is classified as Category C. Pregnancy Category D. First trimester: Associated with Ebstein's anomaly and other congenital heart defects; avoid if possible. Second and third trimesters: Risk of fetal hyperthyr. GYNIX is classified as Category C. First trimester: Inadequate human data; animal studies not available. Theoretical risk based on pharmacologic action. Second and third trimesters: No known fetal harm from topical . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.