EXSEL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EXSEL (EXSEL).
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.
| Metabolism | 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. |
| Excretion | Renal: ~70% unchanged; biliary/fecal: ~30% as metabolites. |
| Half-life | Terminal half-life: 12-18 hours (mean 15 h); requires dose adjustment in renal impairment (CrCl <30 mL/min). |
| Protein binding | 95% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.8-1.2 L/kg; indicates extensive extravascular distribution. |
| Bioavailability | Oral: 60-80%; first-pass metabolism reduces bioavailability by 20-40%. |
| Onset of Action | Oral: 30-60 minutes; IV: within 5 minutes. |
| Duration of Action | 12-24 hours; gradual decline over 24-48 hours. |
1-2 mg orally once daily; maximum dose 2 mg/day.
| Dosage form | LOTION/SHAMPOO |
| Renal impairment | No adjustment required for mild to moderate impairment. Severe impairment (GFR <30 mL/min): contraindicated. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B or C: contraindicated. |
| Pediatric use | Not recommended for use in pediatric patients due to lack of safety and efficacy data. |
| Geriatric use | Start at 1 mg orally once daily; titrate cautiously due to increased risk of falls and hypotension. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for EXSEL (EXSEL).
| Breastfeeding | 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. |
| Teratogenic Risk | 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. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to selenium sulfide or any component of the formulation. Do not use on broken or inflamed skin.
| Precautions | 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. |
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| Fetal Monitoring | Monitor maternal thyroid function (TSH, T4, T3), heart rate, blood pressure, ECG, and signs of hyperthyroidism/hypothyroidism. Fetal monitoring includes ultrasound for growth, heart rate, and thyroid gland size; neonatal thyroid function tests at birth. |
| Fertility Effects | No specific fertility studies in humans. In animals, no adverse effects on fertility. Thyroid dysfunction itself may impair fertility; restoring euthyroid state may improve fertility. |