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Methoxsalen Dosage

Applies to the following strengths: 10 mg; 20 mcg/mL

The information at is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for Psoriasis

Initial dose: Based on patient weight.
<30 kg = 10 mg
30 to 50 kg = 20 mg
51 to 65 kg = 30 mg
66 to 80 kg = 40 mg
81 to 90 kg = 50 mg
91 to 115 kg = 60 mg
>115 kg = 70 mg

The initial UVA exposures are based on the patient's skin type and should be conducted according to the guidelines in professional literature.

Maintenance dose: Dose, schedule, and UVA exposure are based on the patients skin type, grades of erythema, and response to therapy per guidelines in professional literature.

Usual Adult Dose for Cutaneous T-cell Lymphoma

Summary of UVAR photopheresis system (see the UVAR photopheresis system operator's manual for details of this process):
The UVAR system removes a portion of the patient's blood and separates the red blood cells from the white cell layer (buffy coat) by centrifugation. The red cells are returned to the patient and the methoxsalen sterile solution is then injected into the UVAR system and mixed with the buffy coat. The UVAR system then irradiates this drug-cell mixture with ultraviolet light (UVA light, 320 to 400 nm) and returns the treated cells to the patient.

Initial dose: 10 mL (200 mcg) of methoxsalen sterile solution is injected directly into the photoactivation bag during the first buffy coat collection cycle.

Maintenance: Treatment is given on two consecutive days every four weeks.

Duration: Minimum of seven treatment cycles (six months).

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Dose Adjustments

If assessment of the patient during the fourth treatment cycle (approximately 3 months) of the UVAR photopheresis system reveals an increased skin score from the baseline score, the frequency of treatment may be increased to two consecutive treatments every two weeks for a maximum of 20 cycles.


Suitable covering or a topical sunblock (SPF 15 or higher) should follow the therapeutic UVA exposure along with wraparound UVA-absorbing sunglasses for the 24 hour period following treatment with methoxsalen, whether exposed to direct or indirect sunlight in the open or through a window glass.

Patients should not sunbathe for 48 hours after therapy.

Methoxsalen soft-gelatin capsules should not be used interchangeably with regular hard-gelatin capsules. The methoxsalen soft-gelatin capsules exhibit significantly greater bioavailability and earlier photosensitization onset time then hard-gelatin capsules.


Data not available

Other Comments

The blistering of the skin sometimes encountered after UVA exposure generally heals without complication or scarring.

Patients should have an ophthalmologic examination and routine laboratory tests prior to the start of therapy.

There is no clinical evidence to show that treatment with methoxsalen sterile solution beyond six months or using a different schedule provides additional benefit.

Methoxsalen capsules should be taken 1.5 to 2 hours before UVA exposure with some low fat food or milk.