Methoxsalen
Due to it's narrow therapeutic range the use of methoxsalen is limited to isolated cases of vitiligo of the face
Usage
Due to it's narrow therapeutic range the use of methoxsalen is limited to isolated cases of vitiligo of the face
Side effects
- Excessive erythema, nausea, pruritis Headache, dizziness, insomnia, mental excitation and depression may occur. Methoxsalen is potentially hepatotoxic and regular liver function tests must be performed. There is a risk that cataracts may develop and regular ophthalmic assessment is necessary. Chromosomal damage and suspected malignancy have been reported. BURNS: May be minimized and in most cases avoided if certain guidelines are followed: Never treat areas with a 1+ or more erythema unti the erythema present at these sites has resolved. These areas may be shielded during subsequent UV A exposure with zinc oxide or folded cloths. Shield pendulous breasts and abdomens for approximately 1/3 of the UV -A exposure time or until tanning occurs in these areas.These sites have a lower threshold for erythema and are more likely to burn. Avoid unintentional shielding of intertriginous areas and axilla.Burns may occur at these sites if they are first exposed late in the course of therapy. Phototoxicity reactions may first occur as late as 8 hours after ingesting methoxsalen.After treatment is complete benzophenone containing sunscreens or opaque sun blockers should be applied to the area that will be exposed to the sun.Patients should be cautioned to avoid sun exposure, even through window glass, for 6 - 8 hours after methoxsalen + UV -A treatments. They should be instructed to wear sunglasses (grey or green plastic lens) on the day they are been treated. Burns are more apt to occur when the patient is treated having missed a treatment, so that if a patient misses a treatment, the exposure time f the next time is not increased. NAUSEA: This may be minimized by taking the following precautions: Take medication with/after food If mild nausea develops, instruct the patient to take half the total dose 2.5 hours before UV -A exposure and the remainder of the dose 2 hours before treatment. eg. treatment time 16h00: methoxsalen 40mg 20mg at 13h30 20mg at 14h00 Severe nausea not decreased by the above procedure is treated with trimethobenzamine 200 - 400mg with the ingestion of methoxsalen. In intractable cases, the dose of methoxsalen may be decreased by 10mg. PRURITIS: Oral methoxsalen photochemotherapy is occasionally associated with pruritis. Handle as follows: Mild pruritis - frequent application of bland emolients Severe pruritis - heavy doses of antihistamines and/or sedatives. Intractable pruritis unresponsive to the above: Localised - the pruritic area should be shielded from further UV therapy until the pruritis resolves. Generalised - Further treatment should be withheld until the intensity of the pruritis is diminished
Precautions
- CONSIDER THE RISK:BENEFIT RATIO BEFORE PRESCRIBING THE MEDICATION TO BE USED UNDER STRICT MEDICAL SUPERVISION ONLY THERE IS A DANGER OF SEVERE BLISTERING DERMATITIS IF USED INCORRECTLY All patients must wear goggles and should be instructed to close their eyes during treatment with UV light. Patients undergoing therapy should be subject to appropriate supervision so that signs and symptoms of possible toxic effects may be detected and evaluated with minimal delay. There have not been any clinical reports or tests to verify that more severe reactions may result from concomitant ingestion of furocoumarin containing foods while on methoxsalen therapy, but the physician should warn the patient about taking limes, figs, parsley, parsnips, mustard, carrots and celery, might be dangerous. Caution in patients with defective coagulation or in patient treated with anticoagulant drugs. ....see "side-effects" Regular liver function tests should be performed. Regular ophthalmic assessment is necessary. Pregnancy: Methoxsalen is teratogenic and is totally contra-indicated in pregnancy Safety in children under the age of 12 years has not been established and is thus contra-indicated. Chromosomal damage and suspected malignancy has been reported
Who should not take?
- Hepatic insufficiency and those diseases associated with photosensitivity such as porphyria, acute lupus erythematosus, hydroa (any vesicular skin eruption) and polymorphic light eruptions. In leukoderma of infectious origin and in albinism, methoxsalen has no effect on pigmentation. Safety in children under the age of 12 years has not been established and is therefore contra-indicated. No preparation with any photosensitising capacity, internal or external should be used concomitantly. Pregnancy (methoxsalen is teratogenic)
Concentration
- Methoxsalen, 15 mg/capsule
- Methoxsalen, 10 mg/capsule
- Methoxsalen, 10mg/capsule
Available forms
- Tablet, Box 50 Tablets.
- Capsule, Box 20 Capsules.
Related terms
NeomeladinineNeomeladinine FR
UltraMeladinine, UltraMeladinine
