Laboratory monitoring of patients treated with antihypertensive drugs and newly exposed to non steroidal anti-inflammatory drugs: a cohort study.

BACKGROUND: Drug-Drug Interactions between Non Steroidal Anti-Inflammatory Drugs (NSAIDs) and Angiotensin Converting Enzyme Inhibitors (ACEIs), Angiotensin Receptor Blocker (ARBs) or diuretics can lead to renal failure and hyperkalemia. Thus, monitoring of serum creatinine and potassium is recommended when a first dispensing of NSAID occur in patients treated with these drugs. METHODS: We conducted a pharmacoepidemiological retrospective cohort study using data from the French Health Insurance Reimbursement Database to evaluate the proportion of serum creatinine and potassium laboratory monitoring in patients treated with ACEI, ARB or diuretic and receiving a first dispensing of NSAID. We described the first dispensing of NSAID among 3,500 patients of a 4-year cohort (6,633 patients treated with antihypertensive drugs) and analyzed serum creatinine and potassium laboratory monitoring within the 3 weeks after the first NSAID dispensing. RESULTS: General Practitioners were the most frequent prescribers of NSAIDs (85.5%, 95% CI: 84.3-86.6). The more commonly prescribed NSAIDs were ibuprofen (20%), ketoprofen (15%), diclofenac (15%) and piroxicam (12%). Serum creatinine and potassium monitoring was 10.7% (95% CI: 9.5-11.8) in patients treated by ACEIs, ARBs or diuretics. Overall, monitoring was more frequently performed to women aged over 60, treated with digoxin or glucose lowering drugs, but not to patients treated with ACEIs, ARBs or diuretics. Monitoring was more frequent when NSAIDs' prescribers were cardiologists or anesthesiologists. CONCLUSION: Monitoring of serum creatinine and potassium of patients treated with ACEIs, ARBs or diuretics and receiving a first NSAID dispensing is insufficiently performed and needs to be reinforced through specific interventions.