Syed Mohammed Shamim.
Fixed Drug Eruptions: From pharmacological and dermatological view point.
J Pak Assoc Derma Nov ;11(1):27-31.

These are circumscribed lesions that persist or recur at the same site for a period of months and year. The fixed eruptions are essentially a sensitization phenomenon. The drugs produce such eruptions are phenolphthalein, tetracyclines, sulfonamides, oxyphenbutazone, barbiturates, salicylates. There is a long list of drugs which may produce FIDE. The eruption develops within 12 to 72 hours of taking the drug, after withdrawal of the drug the inflammation subsides leaving pigmentation. If the drug is taken again pigmentation recurs. Attacks of fixed drug eruptions only subside when the offending drug is permanently withdrawn. The main mechanisms of continuous drug reactions are pharmacological and immunological. The detailed pathogenesis of the lesions of fixed drug eruptions remain obscure. Forty-five patients attending dermatology clinic of Awane Tijarat-O-Sanat Hospital at North Karachi developed FIDE, within last two years thirty eight were males and seven females. The offending agents were cotrimoxazole, paracetamol, aspirin, mefenamic acid, ibuprofen, indomenthacin, amoxycillin, diclofenac sodium and tetracyclines. In mild cases no treatment is needed only the offending agents should be withdrawn permanently. After subsidence of the eruption deeper pigmentation occurs which takes long time to fade. Symptomatic treatment may be given according to the severity of the lesions. It is concluded that co-trimoxazole was the most offending agent to cause FIDE, other drugs included were paracetamol, aspirin mefenamic acid, ibuprofen, indomethacin, amoxycillin, diclofenac sodium and tetracyclines, precautions should be taken while prescribing the drugs.

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