Two years review of cutaneous adverse drug reaction from first line anti-tuberculous drugs.

First line Anti-TB therapy with rifampicin, isoniazid, pyrazinamide, and ethambutol/streptomycin is very effective. However, major adverse reactions to antituberculous drugs can cause significant morbidity and mortality. Cutaneous adverse drug reaction (CADR) is one of the commonly observed major adverse events. This retrospective study looked at the cases of TB treated in Respiratory Unit, Penang Hospital from January 2004 to December 2005. Of 820 patients treated for active TB, 47 patients (25 females; 22 males) developed CADR (5.7%). CADRs observed include morbiliform rash (72.3%), erythema multiforme syndrome (8.5%), urticaria (8.5%) and others (which include exfoliative dermatitis and lichenoid eruption). Ninety-seven percent of events occurred within two months after the initial dose. Incidence rate of CADR among the first line anti-TB drugs, pyrazinamide was the commonest offending drug (2.38%), followed by streptomycin (1.45%), ethambutol (1.44%), rifampicin (1.23%) and isoniazid (0.98%). Various clinical characteristics of patients with CADR identified include Human Immunodeficiency Virus (HIV) infection (27.7%), polypharmacy (21.3%), elderly (19.1%), autoimmune disorders (6.4%), pre-existing renal impairment (4.3%), pre-existing liver disorders (4.3%). In conclusion, CADR is common and majority of cases occurred within two months after initiation of anti-TB treatment, particularly in HIV infected patients. Pyrazinamide is the commonest offending drug.