RVAbstractPlus> Ismail O.

Department of Clinical Pharmacy, School of Pharmaceutical Sciences,
Universiti Sains Malaysia, 11800, Penang, Malaysia.

Study objective To determine the incidence of and the risk factors
associated with hyperkalemia, induced by ACEI-drug interactions among
cardiac patients. Setting Five medical and cardiology wards of a tertiary
care center in Malaysia. Subjects Five hundred cardiac inpatients, who
received ACEIs concomitantly with other interacting drugs. Method This was a
prospective cohort study of 500 patients with cardiovascular diseases
admitted to Penang Hospital between January to August 2006, who received
ACEIs concomitantly with other interacting drugs. ACEI-drug interactions of
clinical significance were identified using available drug information
resources. Drug Interaction Probability Scale (DIPS) was used to assess the
causality of association between ACEI-drug interactions and the adverse
outcome (hyperkalemia). Main outcome measure Hyperkalemia as an adverse
clinical outcome of the interaction was identified from laboratory
investigations. Results Of the 489 patients included in the analysis, 48
(9.8%) had hyperkalemia thought to be associated with ACEI-drug
interactions. Univariate analysis using binary logistic regression revealed
that advanced age (60 years or more), and taking more than 15 medications
were independent risk factors significantly associated with hyperkalemia.
However, current and previous smoking history appeared to be a protective
factor. Risk factors identified as predictors of hyperkalemia secondary to
ACEI-drug interactions by multi-logistic regression were: advanced age
(adjusted OR 2.3, CI 1.07-5.01); renal disease (adjusted OR 4.7, CI
2.37-9.39); hepatic disease (adjusted OR 5.2, CI 1.08-25.03); taking 15-20
medications (adjusted OR 4.4, CI 2.08-9.19); and taking 21-26 medications
(adjusted OR 9.0, CI 1.64-49.74). Conclusion Cardiac patients receiving
ACEIs concomitantly with potentially interacting drugs are at high risk of
experiencing hyperkalemia. Old age, renal disease, hepatic disease, and
receiving large number of medications are factors that may significantly
increase their vulnerability towards this adverse outcome; thus, frequent
monitoring is advocated.