Adverse drug reactions (ADRs) in patients with heart diseases. Comparison between patients without and with heart failure.

Adverse drug reactions (ADRs) may be more frequent in patients who present some diseases. By means of an intensive prospective drug surveillance work, 492 patients with heart diseases, hospitalized at the Department of Medicine of the Clinical Hospital of the University of Chile, were studied in order to determine the frequency and characteristics of ADRs. ADRs were significantly more frequent in patients with heart failure (HF) (30.0%) than in those without HF (22.7%)(p less than 0.05). Patients presenting HF developed more metabolic disturbances than patients not presenting HF (p less than 0.001). Furosemide was the most frequently used drug in both groups, but treatment with it was longer in patients with HF who presented a significantly higher frequency of adverse reactions to this diuretic (p less than 0.05). 89.9% of ADRs in patients without HF and 93.8% of ADRs in those with HF, were dose-related effects. Analyses of some predisposing factors to ADRs, such as age, number of drugs administered, duration of hospitalization, ADR or allergy histories and presence of a renal failure, did not explain differences found between ADRs in patients without and with HF. These findings suggest that heart failure may be a determinant of frequency and characteristics of ADRs.