8-MOP (Methoxsalen, 8-Methoxypsoralen) Capsules, 10 mg. Methoxsalen is a naturally occurring photoactive substance found in the seeds of the Ammi majus (Umbelliferae) plant and in the roots of Heraclem Candicans. It belongs to a group of compounds known as psoralens, or furocoumarins. The chemical name of methoxsalen is 9-methoxy-7 H-furo[3, 2-g][1]-benzopyran-7-one; it has the following structure:

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Methoxsalen The most commonly reported side effect of methoxsalen alone is nausea, which occurs with approximately 10% of all patients. This effect may be minimized or avoided by instructing the patient to take methoxsalen with milk or food, or to divide the dose into two portions, taken approximately one-half hour apart. Other effects include nervousness, insomnia, and psychological depression. Combined methoxsalen/uva therapy

1. Pruritus: This adverse reaction occurs with approximately 10% of all patients. In most cases, pruritus can be alleviated with frequent application of bland emollients or other topical agents; severe pruritus may require systemic treatment. If pruritus is unresponsive to these measures, shield pruritic areas from further UVA exposure until the condition resolves. If intractable pruritus is generalized, UVA treatment should be discontinued until the pruritus disappears.
2. Erythema: Mild, transient erythema at 24–48 hours after PUVA therapy is an expected reaction and indicates that a therapeutic interaction between methoxsalen and UVA occurred. Any area showing moderate erythema (greater than Grade 2 — see Table 1 for grades of erythema) should be shielded during subsequent UVA exposures until the erythema has resolved. Erythema greater than Grade 2 which appears within 24 hours after UVA treatment may signal a potentially severe burn. Erythema may become progressively worse over the next 24 hours, since the peak erythemal reaction characteristically occurs 48 hours or later after methoxsalen ingestion. The patient should be protected from further UVA exposures and sunlight, and should be monitored closely.
3. Important Differences Between Puva Erythema And Sunburn: PUVA-induced inflammation differs from sunburn or UVB phototherapy in several ways. The in situ depth of photochemistry is deeper within the tissue because UVA is transmitted further into the skin. The DNA lesions induced by PUVA are very different from UV-induced thymine dimers and may lead to a DNA crosslink. This DNA lesion may be more problematic to the cell because crosslinks are more lethal and psoralen-DNA photoproducts may be “new” or unfamiliar substrates for DNA repair enzymes. DNA synthesis is also suppressed longer after PUVA. The time course of delayed erythema is different with PUVA and may not involve the usual mediators seen in sunburn. PUVA-induced redness may be just beginning at 24 hours, when UVB erythema has already passed its peak. The erythema dose-response curve is also steeper for PUVA. Compared to equally erythemogenic doses of UVB, the histologic alterations induced by PUVA show more dermal vessel damage and longer duration of epidermal and dermal abnormalities.
4. Other Adverse Reactions: Those reported include edema, dizziness, headache, malaise, depression, hypopigmentation, vesiculation and bullae formation, non-specific rash, herpes simplex, miliaria, urticaria, folliculitis, gastrointestinal disturbances, cutaneous tenderness, leg cramps, hypotension, and extension of psoriasis.

Read the 8-MOP (methoxypsoralen) Side Effects Center for a complete guide to possible side effectsLearn More »

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Vitiligo Therapy

1. Drug Dosage: Two capsules (10 mg each) in one dose taken with milk or in food two to four hours before ultraviolet light exposure.
2. Light Exposure: The exposure time to sunlight should comply with the following guide:

  Basic Light Skin Color Medium Dark Initial Exposure 15min 20min 25min Second Exposure 20min 25min 30min Third Exposure 25min 30min 35min Fourth Exposure 30min 35min 40min Subsequent Exposure: Gradually increase exposure based on erythema and tenderness of the amelanotic skin. Therapy should be on alternate days and never two consecutive days. Psoriasis Therapy Drug Dosage – Initial Therapy: The methoxsalen capsules should be taken 2 hours before UVA exposure with some food or milk, according to the following table: Patient's(kg) Weight(lbs) Dose(mg) < 30 < 66 10 30-50 66-110 20 51-65 112-143 30 66-80 146-176 40 81-90 179-198 50 91-115 201-254 60 > 115 > 254 70 Additional drug dosage directions are as follows:

1. Weight Change: In the event that the weight of a patient changes during treatment such that he/she falls into an adjacent weight range/dose category, no change in the dose of methoxsalen is usually required. If, in the physician's opinion, however, a weight change is sufficiently great to modify the drug dose, then an adjustment in the time of exposure to UVA should be made.
2. Dose/Week: The number of doses per week of methoxsalen capsules will be determined by the patient's schedule of UVA exposures. In no case should treatments be given more often than once every other day because the full extent of phototoxic reactions may not be evident until 48 hours after each exposure.
3. Dosage Increase: Dosage may be increased by 10 mg. after the fifteenth treatment under the conditions outlined in Section XI.B.4.b.

Uva Radiation Source Specifications & Information Irradiance Uniformity: (For photopheresis, refer to the UVAR* System Operator's Manual.) The following specifications should be met with the window of the detector held in a vertical plane:

1. Vertical variation: For readings taken at any point along the vertical center axis of the chamber (to within 15 cm from the top and bottom), the lowest reading should not be less than 70 percent of the highest reading.
2. Horizontal variation: Throughout any specific horizontal plane, the lowest reading must be at least 80 percent of the highest reading, excluding the peripheral 3 cm of the patient treatment space.

Patient safety features The following safety features should be present: (1) Protection from electrical hazard: All units should be grounded and conform to applicable electrical codes. The patient or operator should not be able to touch any live electrical parts. There should be ground fault protection. (2) Protective shielding of lamps: The patient should not be able to come in contact with the bare lamps. In the event of lamp breakage, the patient should not be exposed to broken lamp components. (3) Hand rails and hand holds: Appropriate supports should be available to the patient. (4) Patient viewing window: A window which blocks UV should be provided for viewing the patient during treatment. (5) Door and latches: Patients should be able to open the door from the inside with only slight pressure to the door. (6) Non-skid floor: The floor should be of a non-skid nature. (7) Thermoregulation: Sufficient air flow should be provided for patient safety and comfort, limiting temperature within the UVA radiator cabinet to approximately less than 100° F. (8) Timer: The irradiator should be equipped with an automatic timer which terminates the exposure at the conclusion of a pre-set time interval. (9) Patient alarm device: An alarm device within the UVA irradiator chamber should be accessible to the patient for emergency activation. (10) Danger label: The unit should have a label prominently displayed which reads as follows: DANGER – Ultraviolet radiation – Follow your physician's instructions – Failure to use protective eyewear may result in eye injury. UVA Exposure Dosimetry Measurements The maximum radiant exposure or irradiance (within ±15 percent) of UVA (320–400 nm) delivered to the patient should be determined by using an appropriate radiometer calibrated to be read in Joules/cm² or mW/cm². In the absence of a standard measuring technique approved by the National Bureau of Standards, the system should use a detector corrected to a cosine spatial response. The use and recalibration frequency of such a radiometer for a specific UVA irradiator chamber should be specified by the manufacturer because the UVA dose (exposure) is determined by the design of the irradiator, the number of lamps, and the age of the lamps. If irradiance is measured, the radiometer reading in mW/cm² is used to calculate the exposure time in minutes to deliver the required UVA dose in Joules/cm² to a patient in the UVA irradiator cabinet. The equation is: Exposure Time in minutes = Desired UVA Dose (J/cm²)/0.06 x Irradiance (mW/cm²) Overexposure due to human error should be minimized by using an accurate automatic timing device, which is set by the operator and controlled by energizing and de-energizing the UVA irradiator lamp. The timing device calibration interval should be specified by the manufacturer. Safety systems should be included to minimize the possibility of delivering a UVA exposure which exceeds the prescribed dose, in the event the timer or radiometer should malfunction. Uva spectral output distribution The spectral distributions of the lamps should meet the following specifications: Wavelength Band (Nanometers) Output1 < 310 < 1 310 to 320 1 to 3 320 to 330 4 to 8 330 to 340 11 to 17 340 to 350 18 to 25 350 to 360 19 to 28 360 to 370 15 to 23 370 to 380 8 to 12 380 to 390 3 to 7 390 to 400 1 to 3 1As a percentage of total irradiance between 320 and 400 nanometers. Puva Treatment Protocol Initial Exposure: The initial UVA exposure should be conducted according to the guidelines presented previously under IX.B.1 and 2, Psoriasis therapy, Drug dosage-initial Therapy and Exposure. Skin Type History Recommended Joules/cm² I Always burn, never tan (Patients with Erythrodermic psoriasis are to be classed as Type I for determination of UVA dosage.) 0.5 J/cm² II Always burn, but sometimes tan 1.0 J/cm² III Sometimes burn, but always tan 1.5 J/cm² IV Never burn, always tan 2.0 J/cm²   Physician Examination V* Moderately pigmented 2.5 J/cm² VI* Blacks 3.0 J/cm² [*Patients with natural pigmentation of these types should be classified into a lower skin type category if the sunburning history so indicates.] Clearing Phase: Specific recommendations for patient treatment are as follows: Skin Types I, II & III. Patients with skin types I, II and III may be treated 2 or 3 times per week. UVA exposure may be held constant or increased by up to 1.0 Joule/cm² at each treatment, according to the patient's response. If erythema occurs, however, do not increase exposure time until erythema resolves. The severity and extent of the patient's erythema may be used to determine whether the next exposure should be shortened, omitted, or maintained at the previous dosage. See ADVERSE REACTIONS section for additional information. Skin Types IV, V & VI. Patients with skin types IV, V and VI may be treated 2 or 3 times per week. UVA exposure may be held constant or increased by up to 1.5 Joules/cm² at each treatment unless erythema occurs. If erythema occurs, follow instructions outlined above in the procedures for patients with skin types I, II and III. Erythrodermic Psoriasis Patients with erythrodermic psoriasis should be treated with special attention because pre-existing erythema may obscure observations of possible treatment-related phototoxic erythema. These patients may be treated 2 or 3 times per week, as a Type I patient. Miscellaneous situations

1. If there is no response after a total of 10 treatments, the exposure of UVA energy may be increased by an additional 0.5–1.0 Joules/cm² above the prior incremental increases for each treatment. (Example: a patient whose exposure dosage is being increased by 1.0 Joule/cm² may now have all subsequent doses increased by 1.5–2.0 Joules/cm².)
2. If there is no response, or only minimal response, after 15 treatments, the dosage of methoxsalen may be increased by 10 mg. (a one-time increase in dosage). This increased dosage may be continued for the remainder of the course of treatment but should not be exceeded.
3. If a patient misses a treatment, the UVA exposure time of the next treatment should not be increased. If more than one treatment is missed, reduce the exposure by 0.5 Joules/cm² for each treatment missed.
4. If the lower extremities are not responding as well as the rest of the body and do not show erythema, cover all other body area and give 25 percent of the present exposure dose as an additional exposure to the lower extremities. This additional exposure to the lower extremities should be terminated if erythema develops on these areas.
5. Non-responsive psoriasis: If a patient's generalized psoriasis is not responding, or if the condition appears to be worsening during treatment, the possibility of a generalized phototoxic reaction should be considered. This may be confirmed by the improvement of the condition following temporary discontinuance of this therapy for two weeks. If no improvement occurs during the interruption of treatment, this patient may be considered a treatment failure.

Alternative exposure schedule As an alternative to increasing the UVA exposure at each treatment, the following schedule may be followed; this schedule may reduce the total number of Joules/cm² received by the patient over the entire course of therapy.

1. Incremental increases in UVA exposure for all patients may range from 0.5 to 1.5 Joules/cm², according to the patient's response to therapy.
2. Once Grade 2 clearing (see Table 2) has been reached and the patient is progressing adequately, UVA dosage is held constant. This dosage is maintained until Grade 4 clearing is reached.
3. If the rate of clearing significantly decreases, exposure dosage may be increased at each treatment (0.1–1.5 Joules/cm²) until Grade 3 clearing and a satisfactory progress rate is attained. The UVA exposure will be held constant again until Grade 4 clearing is attained. These increases may be used also if the rate of clearing significantly decreases between Grade 3 and Grade 4 response. However, the possibility of a phototoxic reaction should be considered; see Non-responsive Psoriasis, above.
4. In summary, this schedule raises slightly the increments (Joules/cm²) of UVA dosage, but limits these increases to those periods when the patient is not responding adequately. Otherwise, the UVA exposure is held at the lowest effective dose.

Maintenance Phase The goal of maintenance treatment is to keep the patient as symptom-free as possible with the least amount of UVA exposure. Schedule Of Exposures: When patients have achieved 95 percent clearing, or Grade 4 response (Table 2), they may be placed on the following maintenance schedules (M1 – M4), in sequence. It is recommended that each maintenance schedule be adhered to for at least 2 treatments (unless erythema or psoriatic flare occurs, in which case see (2a) and (2b) below).

Maintenance Schedules
M1 – once/week
M2 – once/2 weeks
M3 – once/3 weeks
M4 - p.r.n. (i.e., for flares) Length Of Exposure: The UVA exposure for the first maintenance treatment of any schedule (except M4 as noted below) is the same as that of the patient's last treatment under the previous schedule. For skin types I-IV, however, it is recommended that the maximum UVA dosage during maintenance treatments not exceed the following: SKIN TYPES JOULES/CM²/TRE ATMENT I 12 II 14 III 18 IV 22 If the patient develops erythema or new lesions of psoriasis, proceed as follows:

1. Erythema: During maintenance therapy, the patient's tan and threshold dose for erythema may gradually decrease. If maintenance treatments produce significant erythema, the exposure to UVA should be decreased by 25 percent until further treatments no longer produce erythema.
2. Psoriasis: If the patient develops new areas of psoriasis during maintenance therapy (but still is classified as having a Grade 4 response), the exposure to UVA may be increased by 0.5–1.5 Joules/cm² at each treatment; this is appropriate for all types of patients. These increases are continued until the psoriasis is brought under control and the patient is again clear. The exposure being administered when this clearing is reached should be used for further maintenance treatment.

Flares During Maintenance: If the patient flares during maintenance treatment (i.e., develops psoriasis on more than 5 percent of the originally involved areas of the body) his maintenance treatment schedule may be changed to the preceding maintenance or clearing schedule. The patient may be kept on his schedule until again 95 percent clear. If the original maintenance treatment schedule is unable to control the psoriasis, the schedule may be changed to a more frequent regimen. If a flare occurs less than 6 weeks after the last treatment, 25 percent of the maximum exposure received during the clearing phase, may be used and then proceed with the clearing schedule previously followed for this patient. (At 95 percent clearing follow regular maintenance until the optimum maintenance schedule is determined for the patient.) If more than 6 weeks have elapsed since the last treatment was given, treat patients as if they were beginning therapy insofar as exposure dosages are concerned, since their threshold for erythema may have decreased. Table 1. Grades of Erythema
GRADE ERYTHEMA LEVEL 0 No erythema 1 Minimally perceptible erythema—faint pink 2 Marked erythema but with no edema 3 Fiery erythema with edema 4 Fiery erythema with edema and blistering Table 2. Response to Therapy
GRADE CRITERIA PERCENT IMPROVEMENT (COMPARED TO ORIGINAL EXTENT OF DISEASE) -1 Psoriasis worse 0 0 No change 0 1 Minimal improvement—slightly less scale and/or erythema 5-20 2 Definite improvement—partial flattening of all plaques—less scaling and less erythema 20-50 3 Considerable improvement—nearly complete flattening of all plaques but borders of plaques still palpable 50-95 4 Clearing; complete flattening of plaques including borders; plaques may be outlined by pigmentation 95

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See WARNINGS Section. Last reviewed on RxList: 12/15/2008
This monograph has been modified to include the generic and brand name in many instances.

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1. Photochemotherapy (methoxsalen with long wave UVA radiation) is indicated for the symptomatic control of severe, recalcitrant, disabling psoriasis not adequately responsive to other forms of therapy and when the diagnosis has been supported by biopsy. Photochemotherapy is intended to be administered only in conjunction with a schedule of controlled doses of long wave ultraviolet radiation.
2. Photochemotherapy (methoxsalen with long wave ultraviolet radiation) is indicated for the repigmentation of idiopathic vitiligo.
3. Photopheresis (methoxsalen with long wave ultraviolet radiation of white blood cells) is indicated for use with the UVAR* System in the palliative treatment of the skin manifestations of cutaneous T-cell lymphoma (CTCL) in persons who have not been responsive to other forms of treatment. While this dosage form of methoxsalen has been approved for use in combination with photopheresis, Oxsoralen Ultra_ Capsules have not been approved for that use.

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1. Patients exhibiting idiosyncratic reactions to psoralen compounds.
2. Patients possessing a specific history of light sensitive disease states should not initiate methoxsalen therapy. Diseases associated with photosensitivity include lupus erythematosus, porphyria cutanea tarda, erythropoietic protoporphyria, variegate porphyria, xeroderma pigmentosum, and albinism.
3. Patients exhibiting melanoma or possessing a history of melanoma.
4. Patients exhibiting invasive squamous cell carcinomas.
5. Patients with aphakia, because of the significantly increased risk of retinal damage due to the absence of lenses.

Last reviewed on RxList: 12/15/2008
This monograph has been modified to include the generic and brand name in many instances.

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In the event of methoxsalen overdosage, induce emesis and keep the patient in a darkened room for at least 24 hours. Emesis is beneficial only within the first 2 to 3 hours after ingestion of methoxsalen, since maximum blood levels are reached by this time.

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8-MOP Capsules, each containing 10 mg. of methoxsalen (8-methoxypsoralen) packaged in amber glass bottles of 50 (NDC 0187-0651-42). Store at 25°C (77°F); excursions permitted to 15°C–30°C (59°F–86°F). ICN Pharmaceuticals, Inc. 3300 Hyland Ave. Costa Mesa, CA 92626. Rev. 8-98. FDA rev date: 3/26/2003 Last reviewed on RxList: 12/15/2008
This monograph has been modified to include the generic and brand name in many instances.

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Included as part of the WARNINGS section. Last reviewed on RxList: 12/15/2008
This monograph has been modified to include the generic and brand name in many instances.

Source: http://www.rxlist.com