SELENIUM SULFIDE
Clinical safety rating: safe
Animal studies have demonstrated safety
Selenium sulfide is an antifungal and cytostatic agent. It reduces sebum production and inhibits the growth of Malassezia species by interfering with fungal lipid metabolism and cell wall synthesis. The exact molecular mechanism is not fully elucidated.
| Metabolism | Selenium sulfide is minimally absorbed through the skin; systemic metabolism is negligible. Absorbed selenium is incorporated into selenoproteins and excreted in urine and feces. |
| Excretion | Selenium sulfide is minimally absorbed after topical application. The small absorbed fraction is excreted renally as selenite or selenate, with fecal excretion of unabsorbed drug accounting for >90% of the dose. |
| Half-life | Not established; due to negligible systemic absorption, a terminal half-life is not clinically relevant. If absorbed, selenium has a long biological half-life of approximately 65–115 days due to incorporation into selenoproteins. |
| Protein binding | Not applicable due to minimal systemic absorption. Absorbed selenium is bound to plasma proteins, particularly albumin and selenoprotein P, but binding percentage is not defined for selenium sulfide. |
| Volume of Distribution | Not applicable for topical selenium sulfide due to negligible systemic absorption. |
| Bioavailability | Topical: systemic absorption is negligible (<1%). Oral: not a route of administration; accidental ingestion may result in absorption but is toxic. |
| Onset of Action | Topical (shampoo): therapeutic effect on dandruff and seborrheic dermatitis typically occurs within 2–3 applications over 1–2 weeks. |
| Duration of Action | Topical: effects persist for several days to 1 week after a single application, with regular use required to maintain control of symptoms. |
| Molecular Weight | 143.09 |
Topical: 2.5% lotion or shampoo applied to affected area once daily for 7 days; 1% shampoo used once or twice weekly for maintenance.
| Dosage form | LOTION/SHAMPOO |
| Renal impairment | No dosage adjustment required for renal impairment; negligible systemic absorption. |
| Liver impairment | No dosage adjustment required for hepatic impairment; negligible systemic absorption. |
| Pediatric use | Safety and efficacy established for children ≥2 years; apply topical 2.5% lotion or shampoo to affected area once daily for 7 days, or 1% shampoo once or twice weekly. |
| Geriatric use | No specific geriatric dose adjustments; use with caution in patients with severe skin conditions or impaired skin barrier function. |
| 1st trimester | Use only if clearly needed; limited human data. Animal studies not reported. Considered low risk topically. |
| 2nd trimester | Use only if clearly needed; limited human data. Animal studies not reported. Considered low risk topically. |
| 3rd trimester | Use only if clearly needed; limited human data. Animal studies not reported. Considered low risk topically. |
Clinical note
No significant drug interactions For topical use only can cause hair discoloration.
| Placental transfer | No data available; minimal systemic absorption from topical use, thus unlikely significant transfer. |
| Breastfeeding | Topical use is considered compatible with breastfeeding. Avoid application to breast area to prevent infant ingestion. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Common Effects | seborrheic dermatitis |
| Serious Effects |
Hypersensitivity to selenium sulfide or any component of the formulation
| Precautions | Avoid contact with eyes, mucous membranes, and broken skin, May cause local irritation, burning, or dermatitis, Prolonged use may lead to systemic selenium toxicity (selenosis) if excessive amounts are absorbed, Discontinue if irritation or allergic reaction occurs |
| Food/Dietary | No known food interactions. Maintain usual diet unless otherwise advised. |
Loading safety data…
| L2 (Probably Compatible) |
| Teratogenic Risk | Topical selenium sulfide has negligible systemic absorption, thus no known teratogenic risk. Animal studies have not been conducted; however, due to low bioavailability, fetal harm is unlikely regardless of trimester. |
| Fetal Monitoring | No specific monitoring required. Observe for local skin irritation or hypersensitivity reactions. |
| Fertility Effects | No known effects on fertility with topical use. Systemic toxicity from excessive use could theoretically impair fertility, but not anticipated with prescribed topical doses. |
| Clinical Pearls | Apply to affected areas as directed, avoiding broken or inflamed skin. Duration of contact varies by indication: for seborrheic dermatitis, 2-3 min; for tinea versicolor, 10 min before rinsing. Rinse thoroughly to prevent residue. Do not use on large areas of damaged skin due to risk of systemic absorption. Avoid contact with eyes and mucous membranes. Use with caution in patients with history of hypersensitivity. May cause transient hair loss or discoloration. |
| Patient Advice | Shake the lotion well before each use. · Apply only to affected areas of the skin or scalp as directed. · Leave on for the specified time (e.g., 2-10 minutes) before rinsing thoroughly. · Avoid getting the medication in your eyes, mouth, or nose. Rinse with water if accidental contact occurs. · Do not use on broken, inflamed, or infected skin unless directed by your doctor. · Wash hands after application unless treating hands. · Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding. · Notify your doctor if skin irritation, redness, or dryness worsens or persists. · Do not use for longer than prescribed. |