Anti-infectives-induced adverse drug reactions in hospitalized patients

To assess the rate and seriousness of adverse drug reactions (ADRs) attributable to anti-infective agents in hospitalized patients; to estimate the likelihood of experiencing anti-infectives-induced ADRs at different length of drug usage in the hospital; to compare different classes of anti-infectives in inducing ADRs; to determine the impact of age and sex on anti-infectives-induced ADRs.

Prospective cohort study.

Patients admitted to the infectious diseases department at a university teaching hospital, on Sunday to Wednesday, over a 9 months period, who received at least one anti-infective agent were eligible to enter the study.

Any suspected noxious and untoward medical events, including laboratory tests abnormalities following anti-infective therapy.

All patients admitted have received at least one anti-infective drug. Anti-infective agents induced ADRs were detected by interviewing patients and daily chart review. The seriousness, causality, and type of reactions were classified based on World Health Organization (WHO) definitions. Chi-square analysis was performed to assess the influence of sex and age on occurring ADRs. Both Kaplan-Meier and life table method were used to estimate the time to occur the ADR in anti-infective users. To compare the estimated risk of ADRs induced by different classes of anti-infectives, odds ratios were estimated. In all classes of anti-infectives, the odds ratio of each class was estimated with regard to anti-tuberculosis agents, which had the highest prevalence of ADRs.

During the study period, 460 patients were entered the study. During the same period, 38 ADRs were recognized of which 20 (42%) were serious. The most recognized ADRs were suspected to be induced by anti-tuberculosis agents (29.8%). However in comparing with anti-tuberculosis agents, anti-fungal agents were associated with the highest ADR rate (odds ratio [OR], 4.21; 95% confidence interval [CI], 1.41-1.256) whereas cephalosporines were associated with the lowest rate, (OR, 0.1; 95%CI, 0.04-0.26). The survival analysis shows that the likelihood of experiencing an ADR was increased at first 14 days of drug therapy. Also Chi-square analysis shows that greater risk of anti-infectives-induced ADRs was observed in women.

The rate of ADRs induced by anti-infective agents in this study was 8.2%. This is higher than a standard (5%) which has been reported in other studies. This study also shows that some of the classes of anti-infective agents like anti-fungals need more attention.