NIZORAL ANTI-DANDRUFF
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NIZORAL ANTI-DANDRUFF (NIZORAL ANTI-DANDRUFF).
Ketoconazole, an imidazole antifungal agent, inhibits fungal cytochrome P450 14α-demethylase (CYP51), preventing the conversion of lanosterol to ergosterol, an essential component of fungal cell membranes. This disrupts membrane integrity and function.
| Metabolism | Topical application yields minimal systemic absorption; metabolism via hepatic CYP3A4 if absorbed; primarily excreted unchanged in feces. |
| Excretion | Primarily fecal (57%) via biliary excretion as unchanged drug and metabolites; renal excretion accounts for approximately 13% (2-4% unchanged). |
| Half-life | Terminal elimination half-life is biphasic: initial 2 hours, terminal 8 hours (range 6-10 hours). After topical application, systemic absorption is minimal, resulting in an effective half-life of 72-96 hours in skin. |
| Protein binding | 99% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | Vd/F (apparent) is approximately 2.5-3.1 L/kg, indicating extensive tissue distribution. For topical use, systemic Vd is not clinically relevant due to minimal absorption. |
| Bioavailability | Topical: Systemic absorption <1% of applied dose. Oral (tablet): Bioavailability is dose-dependent and variable (mean ~75% in fasting state, increased with acidic pH and food). |
| Onset of Action | Topical: Relief of itching and scaling begins within 2-3 days of daily use; significant reduction in dandruff severity after 1-2 weeks. Oral (systemic use): Onset of antifungal effect within 24-48 hours. |
| Duration of Action | Topical: Effects persist for 7-10 days after discontinuation; regular use (twice weekly) maintains control. Oral: Duration varies with indication; for systemic mycoses, treatment typically continues for weeks. |
| Molecular Weight | 531.43 |
Apply to wet hair, lather, and leave on for 3-5 minutes before rinsing. Use twice weekly for 4 weeks, then as needed to control dandruff.
| Dosage form | SHAMPOO |
| Renal impairment | No dosage adjustment necessary for topical use. No data for systemic exposure. |
| Liver impairment | No dosage adjustment necessary for topical use. No data for systemic exposure. |
| Pediatric use | Safety and effectiveness in children <12 years not established. For children ≥12 years, use same as adult. |
| Geriatric use | No specific dosage adjustment required; use with caution if skin barrier compromised. |
| 1st trimester | Avoid use; topical application of ketoconazole 2% shampoo has minimal systemic absorption, but data are insufficient to recommend use in first trimester; use only if clearly needed. |
| 2nd trimester | Limited data; topical ketoconazole is generally considered low risk due to low systemic absorption; use only if clearly needed. |
| 3rd trimester | Limited data; topical ketoconazole is generally considered low risk; use only if clearly needed. |
Clinical note
Comprehensive clinical and safety monograph for NIZORAL ANTI-DANDRUFF (NIZORAL ANTI-DANDRUFF).
| Placental transfer | Minimal expected due to low systemic absorption after topical application; no specific studies available for shampoo formulation. |
| Breastfeeding | Ketoconazole 2% shampoo has minimal systemic absorption; however, avoid direct application to the nipple area. Use caution and consider alternative therapies if large body surface areas are treated. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to ketoconazole or any component of the formulation
| Precautions | For external use only; avoid contact with eyes, mucous membranes, and broken skin., Discontinue if irritation or sensitization occurs., Do not use occlusive dressings unless directed., Use caution in patients with known hypersensitivity to imidazole antifungals. |
| Food/Dietary | No significant food interactions. |
| Clinical Pearls | Ketoconazole 2% shampoo is effective for seborrheic dermatitis and dandruff. Use twice weekly for 2-4 weeks, then weekly as maintenance. Avoid contact with eyes; if occurs, rinse with water. May cause local irritation or hair discoloration. For tinea versicolor, apply daily for 5 days. Not for internal use. |
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| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Ketoconazole topical (Nizoral Anti-Dandruff) is considered low risk for teratogenicity due to minimal systemic absorption. No specific fetal risks identified in the first trimester; however, systemic ketoconazole is teratogenic in animals and can cause fetal harm if absorbed significantly. For topical use, risk is negligible. |
| Fetal Monitoring | No specific monitoring required for maternal or fetal effects due to minimal systemic exposure. Monitor for local skin reactions; systemic effects unlikely. |
| Fertility Effects | No known adverse effects on fertility with topical use. Systemically, high-dose ketoconazole can impair steroidogenesis and spermatogenesis, but topical application does not achieve significant plasma levels. |
| Patient Advice | Wet hair, apply shampoo, lather, leave for 3-5 minutes before rinsing. · Use twice weekly for dandruff, then weekly for maintenance. · Avoid contact with eyes; if it occurs, rinse thoroughly with water. · May cause temporary hair discoloration or local irritation. · Store at room temperature, away from moisture and heat. |