Methoxsalen

Methoxsalen is a prescription medication used for the treatment of Vitiligo, Psoriasis, and Cutaneous T-Cell Lymphoma. 

• Methoxsalen is available under the following different brand names: 8MOP, Oxsoralen, Oxsoralen Ultra, Uvadex

Common side effects of Methoxsalen include:

• Itching,
• Redness,
• Nausea,
• Nervousness, and
• Sleep problems (insomnia)

Serious side effects of Methoxsalen include:

• Hives,
• Difficulty breathing,
• Swelling of the face, lips, tongue, or throat,
• Severe skin redness within 24 hours after uva treatment,
• Swelling,
• Severe itching,
• Severe skin discomfort,
• Skin redness and swelling with blisters,
• Worsening of psoriasis,
• New skin lesion,
• Moles that have changed in size or color,
• Blurred vision,
• Tunnel vision,
• Eye pain or swelling, and
• Seeing halos around lights

Rare side effects of Methoxsalen include:

• none 

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out. 

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult dosage

Capsule

• 10 mg

Soft capsule

• 10 mg

Lotion

• 1 %

Solution for injection

• 20 mcg/mL (10mL vial)

Vitiligo

Adult dosage

• Oral
  • 20 mg with milk or food 2-4 hours before UV exposure
  • UV exposure: initial 15-25 min (based on skin color); add 5 min on each subsequent exposure (every once in a day) up to erythema/tenderness tolerance
• Topical
  • Apply 1% lotion to the affected area 2 hr before UV exposure every 3-7 days

Psoriasis

Adult dosage

• Take orally with milk or food 2 hours before UVA exposure (every once a day)
• Body weight guidelines
  • Below 30 kg: 10 mg
  • 30-50 kg: 20 mg
  • 51-65 kg: 30 mg
  • 66-80 kg: 40 mg
  • 81-90 kg: 50 mg
  • 91-115 kg: 60 mg
  • Above 115 kg: 70 mg
  • May increase the dose by 10 mg after 15 therapy sessions (do not increase any more than this)

Cutaneous T-Cell Lymphoma

Adult dosage

• Oral
  • Take orally with milk or food 2 hours before UVA exposure
  • Initial dose 0.6 mg/kg
  • If serum concentration is below 50 ng/mL, administer initial dose + 10 mg after 24 hours
• Parenteral
  • Inject 200 mcg (10 mL) into the photoactivation bag of the UVAR photopheresis system
  • Treatment on two consecutive days every 4 weeks for a min. of 7 treatment cycles

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Methoxsalen has severe interactions with no other drugs.
• Methoxsalen has serious interactions with the following drugs
  • fedratinib
  • lonafarnib
  • pirfenidone
  • pomalidomide
• Methoxsalen has moderate interactions with at least 44 other drugs.
• Methoxsalen has minor interactions with the following drugs
  • food
  • ruxolitinib
  • ruxolitinib topical

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• Hypersensitivity to psoralen compounds
• Photosensitive disease states (SLE, etc.), history of melanoma, squamous cell carcinoma (SCC), aphakia

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Methoxsalen?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Methoxsalen?”

Cautions

• Dosages of hard and soft capsules are NOT interchangeable
• Tests before treatment and then every 6-12 months: ophthalmologic exam, CBC, ANA, LFTs, RFTs
• Overdose &/or overexposure could lead to serious burns from UVA or sunlight
• Use appropriate shielding of eyes and unaffected skin during treatment
• Increased risk of SCC, basal cell carcinoma (esp. if the history of radiation treatment or arsenic treatment)
• Wear UVA-absorbing sunglasses for 24 hours post-treatment to avoid cataract formation
• Avoid sun exposure 8 hours post-treatment
• Hepatic disease (hepatic metabolism), cardiac disease (heat stress)
• Severe photosensitivity can occur; advise patients to wear UVA absorbing, wrap-around sunglasses and cover exposed skin or use a sunblock (SPF 15 or higher), and avoid all exposure to sunlight for twenty-four (24) hours following photopheresis treatment
• Do not sunbathe for 24 hours before treatment & for 48 hours post-treatment
• Thromboembolic events, such as pulmonary embolism and deep vein thrombosis, reported with administration through photopheresis systems for the treatment of patients with graft-versus-host disease, a disease for which methoxsalen is not approved

Pregnancy and Lactation

• Use with caution if the benefits outweigh the risks during pregnancy.
• Lactation
  • Not known whether excreted in breast milk; use caution