Postmarketing erfaring har vist, at de alvorligste bivirkninger er Stevens- Johnson syndrom og toksisk epidermal nekrolyse og alvorlig hepatitis/ leversvigt og overfølsomhedsreaktioner, karakteriseret ved udslæt med konstitutionelle symptomer, såsom feber, artralgi, myalgi, lympadenopati samt organpåvirkning, såsom hepatitis, eosinofili, granulocytopeni og nedsat nyrefunktion.
The postmarketing experience has shown that the most serious adverse reactions are Stevens-Johnson syndrome and toxic epidermal necrolysis and serious hepatitis/ hepatic failure and hypersensitivity reactions, characterised by rash with constitutional symptoms such as fever, arthralgia, myalgia and lymphadenopathy, plus visceral involvement, such as hepatitis, eosinophilia, granulocytopenia, and renal dysfunction.