Home > Medical Reference > Encyclopedia (English)

Please install flash player to see this video.

Hospital Virtual Tour

Related Content

Pronunciation:

(meth OKS a len)

U.S. Brand Names:

8-MOP®; Oxsoralen®; Oxsoralen-Ultra®; Uvadex®

Synonyms:

Methoxypsoralen; 8-Methoxypsoralen; 8-MOP

Generic Available:

Canadian Brand Names:

8-MOP®; Oxsoralen®; Oxsoralen-Ultra®; Ultramop™; Uvadex®

Use:

Oral: Symptomatic control of severe, recalcitrant disabling psoriasis; repigmentation of idiopathic vitiligo; palliative treatment of skin manifestations of cutaneous T-cell lymphoma (CTCL)

Topical: Repigmentation of idiopathic vitiligo

Extracorporeal: Palliative treatment of skin manifestations of CTCL

Pregnancy Risk Factor:

C/D (Uvadex®)

Pregnancy Implications:

Fetal toxicity has been observed in animal studies, however, there are no adequate and well-controlled studies in pregnant women. Use during pregnancy is not recommended. Women of childbearing potential should be advised to avoid pregnancy.

Lactation:

Excretion in breast milk unknown/not recommended

Contraindications:

Hypersensitivity to methoxsalen (psoralens) or any component of the formulation; diseases associated with photosensitivity; cataract; invasive squamous cell cancer; aphakia; melanoma; pregnancy (Uvadex®)

Warnings/Precautions:

Serious burns may occur from ultraviolet radiation or sunlight even if exposed through glass if dose and/or exposure schedule is not maintained. Therapy may lead to increased risk of melanoma; this risk may be increased with fair skin or prior exposure to prolonged tar and UVB treatment, ionizing radiation, or arsenic. Methoxsalen concentrates in the lens; eyes should be shielded from light for 24 hours to prevent possible formation of cataracts. Soft-gelatin capsules and hard-gelatin capsule are not interchangeable. Use caution with basal cell carcinoma, hepatic, kidney, cardiac disease, or in the elderly. Use caution with other agents that may cause photosensitivity.

CTCL: For use only if inadequate response to other forms of therapy. Used in conjunction with long wave radiation of white blood cells using the UVAR® photopheresis system. Safety and efficacy in pediatric patients have not been established.

Psoriasis: For use only if inadequate response to other therapies when the diagnosis is biopsy proven. Administer only in conjunction with scheduled controlled doses of long wave ultraviolet (UVA) radiation (combination referred to as PUVA). Safety and efficacy in pediatric patients have not been established.

Vitiligo: Used in conjunction with controlled doses of long wave ultraviolet radiation or sunlight. Lotion should only be applied under direct supervision of prescriber and should not be dispensed to the patient. Safety and efficacy in children <12 years of age have not been established.

Adverse Reactions:

Frequency not always defined.

Cardiovascular: Severe edema, hypotension

Central nervous system: Nervousness, vertigo, depression, dizziness, headache, malaise

Dermatologic: Painful blistering, burning, and peeling of skin; pruritus (10%), freckling, hypopigmentation, rash, cheilitis, erythema, itching, urticaria

Gastrointestinal: Nausea (10%)

Neuromuscular & skeletal: Loss of muscle coordination, leg cramps

Miscellaneous: Miliaria

Overdosage/Toxicology:

Symptoms of overdose include nausea and severe burns. Follow accepted treatment of severe burns. Keep room darkened until reaction subsides (8-24 hours or more).

Drug Interactions:

Substrate of CYP2A6 (minor); Inhibits CYP1A2 (strong), 2A6 (strong), 2C8/9 (weak), 2C19 (weak), 2D6 (weak), 2E1 (weak), 3A4 (weak)

CYP1A2 substrates: Methoxsalen may increase the levels/effects of CYP1A2 substrates. Example substrates include aminophylline, fluvoxamine, mexiletine, mirtazapine, ropinirole, theophylline, and trifluoperazine.

CYP2A6 substrates: Methoxsalen may increase the levels/effects of CYP2A6 substrates. Example substrates include dexmedetomidine and ifosfamide.

Ethanol/Nutrition/Herb Interactions:

Food: Methoxsalen serum concentrations may be increased if taken with food. Avoid furocoumarin-containing foods (limes, figs, parsley, celery, cloves, lemon, mustard, carrots).

Mechanism of Action:

Bonds covalently to pyrimidine bases in DNA, inhibits the synthesis of DNA, and suppresses cell division. The augmented sunburn reaction involves excitation of the methoxsalen molecule by radiation in the long-wave ultraviolet light (UVA), resulting in transference of energy to the methoxsalen molecule producing an excited state ("triplet electronic state"). The molecule, in this "triplet state", then reacts with cutaneous DNA.

Pharmacodynamics/Kinetics:

Protein binding: Reversibly bound to albumin

Metabolism: Hepatic; forms metabolites

Bioavailability: Bioavailability increased with soft-gelatin capsules compared to hard-gelatin capsules; exposure using UVAR® system is ~200 times less than with oral administration

Time to peak, serum:

Hard-gelatin capsules: 1.5-6 hours (peak photosensitivity: ~4 hours)

Soft-gelatin capsules: 0.5-4 hours (peak photosensitivity: 1.5-2 hours)

Half-life elimination: ~2 hours

Excretion: Urine (~95% as metabolites)

Dosage:

Note: Refer to treatment protocols for UVA exposure guidelines.

Children >12 years and Adults: Vitiligo: Topical: Apply lotion 1-2 hours before exposure to UVA light, no more than once weekly

Adults:

Psoriasis: Oral: 10-70 mg 11/2-2 hours before exposure to UVA light; dose may be repeated 2-3 times per week, based on UVA exposure; doses must be given at least 48 hours apart; dosage is based upon patient's body weight and skin type:

<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

>115 kg: 70 mg

Vitiligo: (8-MOP®): Oral: 20 mg 2-4 hours before exposure to UVA light; dose may be repeated based on erythema and tenderness of skin; do not give on 2 consecutive days

CTCL: Extracorporeal (Uvadex®): 200 mcg injected into the photoactivation bag during the collection cycle using the UVAR® photopheresis system (consult user's guide). Treatment schedule: Two consecutive days every 4 weeks for a minimum of 7 treatment cycles

Administration:

Topical: Hands and fingers of person applying the lotion should be protected to prevent possible photosensitization and/or burns.

Dietary Considerations:

To reduce nausea, oral drug can be administered with food or milk or in 2 divided doses 30 minutes apart.

Patient Education:

Inform prescriber of all prescriptions, OTC medications, or herbal products you are taking, and any allergies you have. Do not take any new medication during therapy unless approved by prescriber. This medication is used in conjunction with specific ultraviolet treatment. Take as directed, with food or milk to reduce nausea. Consult prescriber for specific dietary instructions. Avoid use of any other skin treatments unless approved by prescriber. Control exposure to direct sunlight as per prescriber's instructions. If sunlight cannot be avoided, use sunblock (consult prescriber for specific SPF level); wear protective clothing and wraparound protective eyewear. Consult prescriber immediately if burning, blistering, or skin irritation occur. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to become pregnant. Breast-feeding is not recommended.

Dental Health: Effects on Dental Treatment:

No significant effects or complications reported

Dental Health: Vasoconstrictor/Local Anesthetic Precautions:

No information available to require special precautions

Mental Health: Effects on Mental Status:

May cause nervousness, dizziness, or depression

Mental Health: Effects on Psychiatric Treatment:

Concurrent use with psychotropics may produce additive photosensitivity

Dosage Forms:

Capsule:

8-MOP®: 10 mg [hard-gelatin capsule]

Oxsoralen-Ultra®: 10 mg [soft-gelatin capsule]

Lotion (Oxsoralen®): 1% (30 mL) [contains alcohol 71%]

Solution, for extracorporeal administration (Uvadex®): 20 mcg/mL (10 mL) [not for injection]

International Brand Names:

Delsoralen® (ID); Deltasoralen® (IE); Dermox® (MX); Geralen® (PL); Geroxalen® (DK, HU, NL, NO, TR); Macsoralen® (IN); Meladinina® (CR, DO, GT, HN, MX, PA, SV); Meladinine® (BD, CH, DE); Méladinine® (FR); Meladinine® (NL, RO); Melanocyl® (IN); 8-MOP® (AR, CA); Mopsoralen® (BE); Neo-Meladinine® (RO); Oxoralen® (IT, SI); Oxsoralen® (AT, AU, CA, CL, CZ, ES, HK, ID, JO, KW, LB, MX, NL, NZ, PL, RO, SG, ZA); Oxsoralen-Ultra® (CA); Oxsoralon® (BE); Ultramop™ (CA); Uvadex® (CA)

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.