SELENIUM SULFIDE

Clinical safety rating: safe

Animal studies have demonstrated safety

How it works

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.

What the body does with it

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.

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

No significant drug interactions For topical use only can cause hair discoloration.

Breastfeeding	Topical use results in minimal systemic absorption; excretion into breast milk is unlikely. M/P ratio not available. Considered compatible with breastfeeding when used as directed on the scalp.
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

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Common Effects	seborrheic dermatitis
Serious Effects

Absolute Contraindications

["Hypersensitivity to selenium sulfide or any component of the formulation","Application on inflamed, exudative, or abraded skin","Do not use in children under 2 years of age unless directed by a physician"]

Clinical Precautions

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"]

Clinical Tips & Counseling

Drug interactions

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