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Methoxsalen
Synonym(s)
8-Methoxypsoralen; 8-MOP; Ammoidin; Meladinine; Methoxypsoralen; Psoralen; Xanthotoxin
DefinitionThis section has been translated automatically.
Phototoxically active furanocoumarin, which finds its therapeutic application both systemically, as systemic PUVA therapy, or locally, as PUVA bath therapy or PUVA cream therapy. Less frequently, a 0.15% alcoholic methoxsalen solution (= methoxsalen-skin spirit) is applied to the lesional skin.
Ammoidin occurs naturally in Angelica archangelica, Heraculum sphondylium and other apiaceae (Roth L 1984).
Pharmacodynamics (Effect)This section has been translated automatically.
Therapeutically useful, phototoxic substance: Interaction between methoxsalen and long-wave UV light, formation of photoadduction products between methoxsalen molecule and the thymine part of the DNA with resulting reduction of cell division. UVmax 365 nm.
IndicationThis section has been translated automatically.
psoriasis; vitiligo; circumscribed scleroderma; systemic scleroderma; cutaneous T-cell lymphoma; most severe forms of atopic eczema
Limited indicationThis section has been translated automatically.
Pregnancy, lactation (extensive application), children < 12 years, severe liver or kidney diseases (application > 1/3 of the body surface), orthostatic dysregulation.
Dosage and method of useThis section has been translated automatically.
- PUVA local: see below PUVA cream therapy or PUVA bath therapy.
- PUVA systemic: 20-40 mg to be taken 1 hour before irradiation. S.u. PUVA therapy, systemic.
Standard concentrationThis section has been translated automatically.
Extracorporeal photopheresis: injection of the 2% solution directly into the photopheresis system during the first buffy coat collection cycle, followed by irradiation for 90 minutes
. This method of application significantly reduces gastrointestinal side effects in particular! PUVA-glasses must still be worn!
InteractionsThis section has been translated automatically.
See Table 1.
ContraindicationThis section has been translated automatically.
Z.n. basal cell carcinoma; spinocellular carcinoma; malignant melanoma; M. Bowen; combination with other photosensitizers, other phototoxic (e.g. tetracyclines, phenothiazines, furanocoumarins) or photoallergic drugs ( photoallergenic); for porphyria erythropoetica congenita; porphyria cutanea tarda; for z.n. radiatio, hypersensitivity to the active substance, application to the eye or mucous membranes; extensive application in lupus erythematosus
PreparationsThis section has been translated automatically.
Meladinine; Oxsoralen (available through the international pharmacy)
Note(s)This section has been translated automatically.
- Psoralenes belong to the group of tricyclic aromatics consisting of a human ring and a coumarin (furanocoumarins). They occur naturally in very small quantities in certain fruits and vegetables (e.g. figs, limes), but also in certain grasses (e.g. St. John's wort, yarrow, hogweed). The aflatoxins also belong to the furanocoumarins.
- Psoralenes are actually chemically inert molecules which are only activated by absorption of UV-A for a few millionths of a second. The optimal activating wavelength is 365 nm, therefore UV lamps with filtered spectrum are used for PUVA therapy and extracorporeal photopheresis. Under the 365 nm irradiation optimum, methoxsalene (8-MOP) forms a link with the DNA double strand (so-called cross-linking between 2 pyrimidine bases with the formation of photoadducts).
LiteratureThis section has been translated automatically.
- de Oliveira DM et al. (2016)The classical photoactivated drug 8-methoxypsoralen and related compounds are effective without UV light irradiation against glioma cells. Neurochem Int 99:33-41.
- Learn DB et al.(2016) Clinical Observations versus Histopathological Findings. Toxicol Pathol 44:545-551.
Roth L et al (1984) Plant toxins- xanthotoxin. In: Roth L et al. (Eds)Poisonous plants, plant allergy. Nikol publishing company mbH Hamburg S 954
- Weitz M et al (2015) Extracorporeal photopheresis versus alternative treatment for chronic graft-versus-host disease after haematopoietic stem cell transplantation in paediatric patients. Cochrane Database Syst Rev doi: 10.1002/14651858.
- Zic JA (2015)Extracorporeal Photopheresis in the Treatment of Mycosis Fungoides and Sézary Syndrome. Dermatol Clin 33:765-776.
TablesThis section has been translated automatically.
Significant interactions of methoxsalene
Coumarins |
Bleeding tendency ↑ |
Methotrexate |
Carcinogenicity ↑ |
Phenothiazines |
Photosensitization |
Coal tar |
Carcinogenicity ↑ |
Tetracyclines |
Photosensitization |
Tolbutamide |
Methoxsalen mirror ↑ |