Methoxsalen	(meth-OX-a-len)
Trade Name(s):	8-MOP   ·Capsules 10 mg   Oxsoralen   ·Lotion 1% (10 mg/mL)   Oxsoralen-Ultra   ·Capsules, soft gelatin 10 mg   Uvadex   ·Solution, extracorporeal 20 mcg/mL Indicates Canadian Trade Name.
Class:	Psoralen
Action:	Exact mechanism not known; however, methoxsalen acts as a photosensitizer. Absorption:
	8-MOP 8-MOP - Max bioavailability is reached 1.5 to 3 h after oral administration and lasts up to 8 h.
	Oxsoralen-Ultra Oxsoralen-Ultra - Reaches peak blood drug levels in 0.5 to 4 h, and detectable levels are observed up to 12 h.
	Distribution: Methoxsalen is reversibly bound to serum albumin and preferentially taken up by epidermal cells.
	Metabolism: Methoxsalen is rapidly metabolized.
	Excretion: Approximately 95% is excreted as a series of metabolites in the urine within 24 h.
	Oxsoralen-Ultra Oxsoralen-Ultra - The half-life is approximately 2 h.
	Duration:
	8-MOP 8-MOP - Time of peak photosensitivity is 3.9 to 4.25 h.
	Oxsoralen-Ultra Oxsoralen-Ultra - Time of peak photosensitivity is 1.5 to 2.1 h.
Indications:	Symptomatic control of severe, recalcitrant, disabling psoriasis not responsive to other forms of therapy and when diagnosis is supported by biopsy ( Oxsoralen-Ultra , 8-MOP capsule); use in conjunction with long-wave UV radiation for repigmentation of idiopathic vitiligo ( 8-MOP capsule, Oxsoralen lotion); with long-wave UV radiation of white blood cells (photopheresis) with the UVAR photopheresis system in the palliative treatment of skin manifestations of cutaneous T-cell lymphoma in people not responsive to other forms of treatment ( 8-MOP capsule); extracorporeal administration with UVAR photopheresis system in the palliative treatment of skin manifestation of cutaneous T-cell lymphoma that is unresponsive to other forms of treatment ( Uvadex solution).
Contraindications:	Children younger than 12 yr of age ( Oxsoralen lotion); patients exhibiting idiosyncratic reactions to psoralen compounds; patients with a specific history of light-sensitive disease states should not initiate methoxsalen therapy (eg, albinism, erythropoietic protoporphyria, lupus erythematosus, porphyria cutanea tarda, variegate porphyria, xeroderma pigmentosum); patients exhibiting melanoma or possessing a history of melanoma; patients exhibiting invasive squamous cell carcinomas; patients with aphakia, because of increased risk of retinal damage caused by absence of lenses.
Interactions:
	Known photosensitizers (eg, anthralin, coal tar, coal tar derivatives, fluoroquinolone antibiotics, griseofulvin, halogenated salicylanilides, nalidixic acid, organic staining dyes [eg, methylene blue, methyl orange, rose bengal, toluidine blue], phenothiazines, sulfonamides, tetracyclines, thiazide diuretics) Exercise care when using these agents and methoxsalen concurrently.
Lab Test Interferences:	None well documented.
Adverse Reactions:
	cardiovascular:
	8-MOP , Oxsoralen-Ultra Hypotension.
	Uvadex Hypotension (secondary to extracorporeal volume [ more than 1% ] ).
	cns:
	8-MOP , Oxsoralen-Ultra Depression, dizziness, headache, insomnia, malaise, nervousness.
	dermatologic:
	8-MOP , Oxsoralen-Ultra Pruritus (10%); cutaneous tenderness, erythema, extension of psoriasis, folliculitis, hypopigmentation, nonspecific rash, urticaria, vesiculation and bullae formations.
	Oxsoralen lotion Severe burns from overexposure to UVA.
	gi:
	8-MOP , Oxsoralen-Ultra Nausea (10%); GI disturbances.
	miscellaneous:
	8-MOP , Oxsoralen-Ultra Edema, herpes simplex, leg cramps, miliaria.
	Uvadex Infection.
Precautions:
Warning:	Methoxsalen should only be used by health care providers who have special competence in the diagnosis and treatment of psoriasis and vitiligo ( 8-MOP , Oxsoralen-Ultra ) or cutaneous T-cell lymphoma ( Uvadex ) and who have special training and experience in photochemotherapy. For treatment of patients with psoriasis, restrict photochemotherapy to patients with severe, recalcitrant, disabling psoriasis that is not adequately responsive to other forms of therapy, and only when the diagnosis is certain. 8-MOP may not be interchanged with Oxsoralen-Ultra capsules without retitration of the patient. Oxsoralen-Ultra has greater bioavailability and earlier photosensitization onset time than previous forms. Fully inform patient of the possibilities of ocular damage, aging of the skin, and skin cancer.
	Monitoring: 8-MOP , Oxsoralen-Ultra : Patients should have an ophthalmologic examination prior to the start of therapy and then yearly. Prior to starting therapy and 6 to 12 mo subsequently, patients should have the following tests: CBC, antinuclear antibodies, LFTs, and renal function tests.
	Pregnancy: Category C ( 8-MOP , Oxsoralen lotion, Oxsoralen-Ultra ); Category D ( Uvadex ).
	Lactation: Undetermined.
	Children: Safety and efficacy not established.
	Oxsoralen lotion Safety and efficacy not established in children younger than 12 yr of age.
	Elderly: Use with caution, usually starting at the low end of the dosage range, because of the greater frequency of decreased hepatic, renal, or cardiac function, and concomitant diseases or other drug therapy. Use with particular caution in patients with preexisting history of cataract, CV conditions, kidney and/or liver dysfunction, or skin cancer.
	Hepatic function impairment: Because hepatic biotransformation is necessary for drug urinary excretion, use with caution.
	Carcinogenesis: Risk of squamous cell carcinoma among PUVA-treated patients is increased (especially in patients who are fair-skinned or have had pre-PUVA exposure to prolonged tar and UVB treatment) ionizing radiation, or arsenic. Risk of basal cell carcinoma may also be increased.
	Special risk patients: Diligently observe and treat patients with basal cell carcinoma or a history of basal cell carcinoma; diligently observe patients with a history of previous x-ray therapy, grenz ray therapy, or arsenic therapy for signs of carcinoma; patients with cardiac disease or others who may be unable to tolerate prolonged standing or exposure to heat stress should not be treated in a vertical UVA chamber.
	Actinic degeneration Exposure to sunlight and/or UV radiation may result in premature aging of the skin.
	Cataract Because the concentration of methoxsalen in the lens is proportional to the serum level, if the lens is exposed to UVA while methoxsalen is present, photochemical action may lead to irreversible binding of the methoxsalen to proteins and DNA components of the lens.
	Skin burning Serious burns from either UVA or sunlight, even through window glass, can result if recommended dosage and/or exposure schedules are not maintained.
	Sunbathing The presence of sunburn may prevent the accurate evaluation of the patient's response to photochemotherapy.
	Total dosage Total cumulative dose of UVA that can be given safely over long periods of time has not been established.
Overdosage:	Signs & symptoms Severe burns from overexposure to UVA.
Patient/Family Education:	Advise patient that response to therapy is not rapid and that it may take weeks to months to achieve max benefit. Advise patient that ingesting limes, figs, parsley, parsnips, mustard, carrots, or celery might cause an exaggerated response to the UVA treatments or the sun and to ingest carefully until tolerance is determined. Advise patient to read the Patient Package Insert before starting therapy and with each refill. Advise patient that nausea is a common side effect and to take each dose with food or milk to minimize this problem. If nausea still occurs, advise patient to divide the dose into 2 portions taken approximately 30 min apart with food or milk. Caution patient to take the dose exactly as prescribed and to carefully follow the timing recommendations between taking the dose and starting the UVA treatment. Advise patient that serious burns can result if drug dosing schedules and/or UVA exposure schedules are not followed. Instruct patient to wear UVA-absorbing, wraparound sunglasses for the 24-h period following ingestion of methoxsalen, whether exposed to direct or indirect sunlight outside or through a glass window. Caution patient not to sunbathe during the 24 h prior to and 48 h after taking methoxsalen and UVA treatment. Caution patient to avoid exposure to sunlamps and the sun, even through windows or cloud cover, for at least 8 h after taking methoxsalen. If sun exposure cannot be avoided, instruct patient to wear protective devices (eg, hat, gloves), and/or apply sunscreen that filters out UVA radiation (“UVA protection”) with a sun protection factor (SPF) of 15 or more. Instruct patient to apply sunscreen to all areas that might be exposed to the sun, including lips, but not to apply until after the UVA treatment. Advise patient that if itching occurs in UVA-treated areas, to frequently apply a bland emollient. If itching persists or worsens, advise patient to notify health care provider. Advise patient to frequently examine skin for small growths or sores that do not heal. Instruct patient to inform health care provider immediately if noted. Caution patients that during PUVA therapy, total UVA-absorbing/blocking goggles mechanically designed to give max ocular protection must be worn. Failure to do so may increase the risk of cataract formation. Abdominal skin, breasts, genitalia, and other sensitive areas should be protected for approximately 33% of the initial exposure time until tanning occurs. Unless affected by disease, male genitalia should be shielded. Caution patients that after combined methoxsalen/UVA therapy, UVA-absorbing wraparound sunglasses should be worn during the daylight for 24 h after combined methoxsalen/UVA therapy. Advise patient to notify health care provider if nausea, itching, redness, tenderness, or blistering of skin occurs and lasts more than 24 to 48 h. Advise patient that lotion will be applied by a health care provider in a health care setting before undergoing UVA treatment. Instruct patient to keep the treated areas protected from sunlight by wearing protective clothing or applying a sunscreen with UVA protection and an SPF of 15 or more. Advise patient that the area of application may be highly sensitive to sunlight or sunlamps for several days after application. Advise patient that blood will be drawn and sent to the lab where this medication will be used to treat the patient's white blood cells. Once the treatment has been completed, the treated white blood cells will be returned to their body. Instruct patient to wear UVA-absorbing, wraparound sunglasses and to cover exposed skin or use a sunblock with UVA protection and an SPF of 15 or more for the 24-h period following treatment.