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DERMATOLOGICALS › ANTIPSORIATICS › ANTIPSORIATICS FOR TOPICAL USE › Psoralens for topical use
methoxsalen
D05AD02
Forms & Strengths
- Oral capsules: 10 mg
- Topical lotion: 1%
Adult Dosing
- Psoriasis (PUVA): 10-70 mg orally as a single dose 1.5 to 2 hours before UVA exposure, based on body weight (0.6 mg/kg)
- Cutaneous T-cell lymphoma (Extracorporeal photopheresis): 200 mcg/mL processed via specialized system
Pediatric Dosing
- Safety and efficacy in pediatric patients under 12 years not established for oral PUVA
Indications
- Symptomatic severe recalcitrant psoriasis unresponsive to other therapy
- Palliative treatment of cutaneous T-cell lymphoma (extracorporeal photopheresis)
Mechanism of Action
- Intercalates into DNA upon photoactivation by UVA radiation, forming covalent mono- and bi-functional adducts (cross-links)
- Inhibits DNA synthesis, suppresses cellular proliferation, and modulates immune responses
Contraindications
- Idiosyncratic reactions to psoralens
- Melanoma or history of invasive squamous cell carcinoma
- Aphakia (due to increased risk of retinal damage)
- Lupus erythematosus, porphyria, or other photosensitive disease states
- Concomitant use with strong cutaneous photosensitizing agents
Adverse Reactions
- Nausea and vomiting
- Erythema, pruritus, and burning from phototoxicity
- Premature skin aging and increased risk of non-melanoma skin cancers
- Cataract formation without UV-blocking eye protection
- Dizziness, headache, and nervousness
Drug Interactions
- Concomitant use with other photosensitizing drugs (e.g., tetracyclines, sulfonamides, phenothiazines, thiazides) increases risk of severe phototoxicity
- Topical coal tar or anthralin concurrent use may heighten cutaneous irritation
Curated Content: Needs Vetting Before Put to Clinical Use