Has cross sensitivity been described between acetazolamide and sulphadiazine?/nBackground: A patien

Fråga: Has cross sensitivity been described between acetazolamide and sulphadiazine?

Background: A patient with AIDS and an increased intracranial pressure needs to be treated with acetazolamide (Diamox). Earlier the patient developed an exanthema during sulphadiazine (Trimin sulfa) treatment.

Sammanfattning: No clinical documentation concerning a cross sensitivity between acetazolamide and sulphonamide could be located. The risk seems low considering the widespread use of both drugs.

Svar: Sulphadiazine belongs to the group of sulphonamide derivates (1). Hypersensitivity reactions due to treatment with sulphonamides, may rarely occur in patients treated with carbonic anhydrase inhibitors such as acetazolamide (2). In FASS hypersensitivity reactions due to treatment with sulphonamides is stated as a contraindication for the use of acetazolamide (1).

Acetazolamide may occasionally cause side effects, similar to those caused by bacteriostatic sulphonamides, particulary during long term therapy. These reactions include fever, blood dyscrasias and sometimes skin toxicity such as exfoliative dermatitis (3). The manufacturer is aware of a few reports of sulphonamide-type hypersensitivity reactions due to acetazolamide, but none of these reactions occurred in a patient with a well documented history of sulpha allergy (4). Documentation concerning the potential for cross reactivity is lacking. The chemical structures of acetazolamide and sulphonamides are not closely related (5). An old article describes a patient with mitral stenosis and sulpha allergy who developed symptoms of oedema, respiratory distress and hemoglobinuria during acetazolamide treatment. However, it was unclear if this was an allergic reaction or a worsening of the congestive heart failure in this patient (6). 1 FASS 1998 (The Swedish catalogue of approved medical products)

2 Drugline no 12793 (year 1995)
3 Wyeth Lederle, product information
4 Personal communication, M-L Olsson, Wyeth Lederle
5 Expert consultation, Gunnel Tybring, Department of Clinical Pharmacology, Huddinge Hospital

6 Stock JG: Sulfonamide hypersensitivity and acetazolamide. Arch Ophthalmol 1990; 108: 634-635