Last reviewed 2026-04-20 · How we verify

Oxsoralen-Ultra (METHOXSALEN)

Oxsoralen-Ultra works by generating free radicals when exposed to ultraviolet A (UVA) light, which helps to slow down the growth of skin cells and reduce inflammation.

Oxsoralen-Ultra (METHOXSALEN) is a photoactivated radical generator, a small molecule drug that targets Cytochrome P450 1A2. It was originally developed and is currently owned by Valeant Pharm Intl, and has been FDA-approved since 1954 for the treatment of Primary cutaneous T-cell lymphoma, Severe Recalcitrant Psoriasis, and Vitiligo. As an off-patent medication, it is available from generic manufacturers. Key safety considerations include the risk of severe sunburn and potential interactions with other medications. Oxsoralen-Ultra requires careful dosing and sun exposure to minimize adverse effects.

At a glance

Mechanism of action

Mechanism of action. The exact mechanism of action of methoxsalen is not known. The best-known biochemical reaction of methoxsalen is with DNA. Methoxsalen, upon photoactivation, conjugates and forms covalent bonds with DNA which leads to the formation of both monofunctional (addition to single strand of DNA) and bifunctional adducts (crosslinking of psoralen to both strands of DNA). Reactions with proteins have also been described. The formation of photoadducts results in inhibition of DNA synthesis, cell division and epidermal turnover.For the palliative treatment of Cutaneous T-Cell Lymphoma, Photopheresis consists of removing portion of the patients blood and separating the red blood cells from the white cell layer (buffy coat) by centrifugation. The red cells are returned to the patient and the UVADEX(R) Sterile Solution is then injected into the instrument and mixed with the buffy coat. The instrument then irradiates this drug-cell mixture with ultraviolet light (UVA light, 320-4

Approved indications

• Palliative treatment of CTCL skin manifestations

Boxed warnings

• UVADEX ® (methoxsalen) Sterile Solution should be used only by physicians who have special competence in the diagnosis and treatment of cutaneous T-cell lymphoma and who have special training and experience in the THERAKOS ® CELLEX ® Photopheresis System. Please consult the CELLEX ® Operator's Manual before using this product.

Common side effects

• Nausea
• Pruritus
• Erythema
• Edema
• Dizziness
• Headache
• Malaise
• Depression
• Hypopigmentation
• Vesiculation
• Bullae formation
• Non-specific rash

Drug interactions

• CYP2A6 Substrates

Key clinical trials

• Impact of ExtraCorporeal Phototherapy (ECP) on Auxiliary Follicular T-lymphocytes and Circulating B-lymphocytes During Chronic AntiBody-Mediated Rejection in Kidney Transplantation. (NA)
• Single Patient Compassionate Use of X-PACT in Salvage Treatment of Prostate Cancer
• X-ray Psoralen Activated Cancer Therapy in Head and Neck, Breast, Sarcoma and Melanoma (PHASE1)
• Extracorporeal Photopheresis in Sezary Syndrome
• EPIC- Extracorporeal Photopheresis (ECP) for Immune-related Colitis (PHASE2)
• Prevention of GVHD in Patients Treated With Allogeneic SCT: Possible Role of Extracorporeal Photophoresis (NA)
• Photopheresis in Early-stage Mycosis Fungoides (PHASE2)
• Photopheresis in GvHD After Hematopoietic Transplantation: Characteristics of the Procedure and of the Cell Product

Primary sources

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Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Oxsoralen-Ultra CI brief — competitive landscape report
• Oxsoralen-Ultra updates RSS · CI watch RSS
• Bausch Health portfolio CI