Potential drug-disease interactions and drug-related problems in older adults with chronic hypertension and/or diabetes

Background: The older adults are at greater risk for developing adverse drug events due to both age-related comorbidities and polypharmacy practice. Objectives. To evaluate the drug-drug interaction (DDI) potential and drug therapy related problems (DRP) expected in community-dwelling older adults with chronic multiple morbidities in Bahrain. Design: Prescription-based retrospective audit. Setting: Primary care settings, Bahrain. Method: A nationwide audit of 2,090 primary care prescriptions, exploring potential DDI, in patients aged ≥65 years in Bahrain. Results: Approximately one-quarter of the older adults were on acid-suppressing drugs (ASD), mostly on long-term basis (mean 4 ±1 months). Twenty percent (211/1,073) of diabetic patients received concomitant metformin and ASD, both of which are known to cause vitamin B12 deficiency. Lipophilic statins (atorvastatin and simvastatin) and proton pump inhibitors (omeprazole/esomeprazole), which may interfere with clopidogrel efficacy, were prescribed in 63.8% (30/47) and 30.8% (4/13) of patients, respectively. Other potentially inappropriate prescriptions included: β-antagonists with insulin(s), glyburide or their combinations (3.2%; 34/1,073); paracetamol >4 gm/d (1.1%; 22/2,090); indapamide with QT prolonging drugs (0.9%; 19/2,090); cardioselective β,-antagonists in patients with airway diseases (0.8%; 16/2,090); supratherapeutic dose of Bipreterax® and metformin; and subtherapeutic dose of pregabalin, calcium supplements and vitamins. Conclusions: The spectrum of DDI and expected DRP suggests mild to hazardous ADR potential of many prescriptions issued to older adults with chronic morbidities. Interventions are needed to decrease the risk of potential adverse drug events that compromise older adult patient safety