Clinical features of tiaprofenic acid (surgam) associated cystitis and a study of risk factors for its development.

A case-control study was performed to describe the clinical course and identify risk factors predisposing to the development of tiaprofenic acid associated cystitis. Cases were identified from reports to the Australian Adverse Drug Reactions Advisory Committee and a two-year (1995-1996) national surveillance programme. Definition of a case was onset of symptoms of cystitis while taking tiaprofenic acid with pyuria (>10 WBC/microl) and/or hematuria (>10 RBC/microl), and no evidence of urinary tract infection. Definitions of "prescriber-matched" and "unmatched" controls were those who had been prescribed tiaprofenic acid by the same prescriber within 12 months of the case without developing cystitis or were identified from the databases of local pharmacies of the cases respectively. 81 of 109 identified cases and 109 of 184 potential controls completed a standardised interviewer-administered questionnaire. Median time between the commencement of tiaprofenic acid and symptom onset was 6. 3 months (range 0.1-47.1 months). Median interval between presentation to doctor and drug cessation was 3.0 months (range 0-24. 5 months). In half the patients, symptoms resolved within 14 days of ceasing therapy. Increasing age was a risk factor for the development of tiaprofenic-acid associated cystitis, age >70 years-odds ratio 3.2 (95% confidence interval 1.3-7.9) compared with age <55 years. Patients taking aspirin had a reduced risk (odds ratio 0.3, 95% confidence interval 0.1-0.9). Dose and amount of fluid consumed per day were not related to the risk of cystitis. Earlier recognition of tiaprofenic acid associated cystitis can potentially reduce the morbidity related to this condition. Apart from an increased risk among older patients, it is likely that this condition represents a drug reaction that cannot be predicted from clinical variables.