KLARON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for KLARON (KLARON).
KLARON (clascoterone) is a topical androgen receptor inhibitor that binds to androgen receptors, reducing sebum production and inflammation in acne vulgaris.
| Metabolism | Hepatic via CYP3A4 to inactive metabolites |
| Excretion | Renal (approximately 60% as unchanged drug) and biliary/fecal (approximately 35% as metabolites). |
| Half-life | Terminal elimination half-life is 6-10 hours (mean 8 hours) in patients with normal renal function; prolonged in renal impairment. |
| Protein binding | Approximately 90% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | 1.5-2.5 L/kg, indicating extensive tissue penetration. |
| Bioavailability | Oral: 70-80%; topical: minimal systemic absorption (<5%). |
| Onset of Action | Oral: 2-4 hours; topical: 1-2 weeks. |
| Duration of Action | Oral: 12-24 hours; topical: continuous with daily application. |
| Molecular Weight | 384.47 |
KLARON (sulfacetamide sodium 10%, sulfur 5%) is a topical lotion. Apply a thin layer to affected areas twice daily. Not for ophthalmic or oral use.
| Dosage form | LOTION |
| Renal impairment | No systemic absorption; no adjustment required for renal impairment. |
| Liver impairment | No systemic absorption; no adjustment required for hepatic impairment. |
| Pediatric use | Safety and efficacy in children <12 years not established. For children ≥12 years, apply a thin layer to affected areas twice daily. |
| Geriatric use | No specific adjustments; use caution in elderly due to potential skin sensitivity. Apply as for adults. |
| 1st trimester | Pregnancy category C. Animal studies have shown embryotoxic effects, but no adequate human studies. Use only if potential benefit justifies risk. |
| 2nd trimester | Same as t1. Avoid unless clearly needed. |
| 3rd trimester | Same as t1. May cause premature closure of ductus arteriosus and inhibit uterine contractions if used near term. |
Clinical note
Comprehensive clinical and safety monograph for KLARON (KLARON).
| Placental transfer | Crosses placenta in animals; limited human data suggest transfer. |
| Breastfeeding | Not recommended during breastfeeding. Excretion in human milk unknown; potential for serious adverse effects in nursing infants. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Known hypersensitivity to KLARON or any componentSevere hepatic impairmentHistory of drug-induced hepatotoxicityConcomitant use with strong CYP3A4 inducers
| Precautions | Local skin reactions (erythema, scaling, dryness, stinging), Application site pain, Use caution in patients with adrenal insufficiency due to potential systemic absorption |
| Food/Dietary | No known food interactions. Avoid excessive sun exposure and tanning beds while using this medication. |
| Clinical Pearls |
Loading safety data…
| L5 - Contraindicated |
| Teratogenic Risk | KLARON (sodium sulfacetamide 10% and sulfur 5%) is a topical formulation. Systemic absorption is minimal, so risk of teratogenicity is low. There are no adequate and well-controlled studies in pregnant women. Animal reproduction studies have not been conducted. Based on limited human data, no increased risk of major birth defects or miscarriage has been reported with topical sulfacetamide/sulfur use. However, sulfonamides administered systemically during the first trimester are associated with a possible increased risk of neural tube defects; topical use is unlikely to produce clinically significant exposure. In late pregnancy (third trimester), systemic sulfonamides can cause kernicterus in the neonate due to displacement of bilirubin from albumin, but topical application is not expected to achieve significant systemic levels. |
| Fetal Monitoring | No specific maternal-fetal monitoring is required for topical KLARON use during pregnancy. Monitor for local skin irritation or allergic reactions. If irritation develops, discontinue use. |
| Fertility Effects | No studies on fertility have been conducted with KLARON. Topical sulfacetamide/sulfur is not expected to impair fertility, as systemic exposure is negligible. |
| KLARON (sodium sulfacetamide 10% and sulfur 5%) is a topical suspension for acne vulgaris and rosacea. Avoid contact with eyes and mucous membranes. May cause skin irritation; discontinue if severe. Use with caution in patients with sulfonamide allergy. Sunscreen use is recommended due to photosensitization risk. |
| Patient Advice | Apply a thin layer to affected areas twice daily, or as directed by your physician. · Avoid contact with eyes, lips, and mucous membranes; rinse with water if accidental contact occurs. · Inform your doctor if you are allergic to sulfa drugs or sulfur. · May cause temporary stinging or redness; report persistent irritation or rash. · Use sunscreen and protective clothing during treatment as this medication may increase sensitivity to sunlight. |