NSAID-antihypertensive drug interactions: which outpatients are at risk for a rise in systolic blood pressure?

Background: Management guidelines for drug-drug interactions between non-steroidal anti-inflammatory drugs (NSAIDs) and antihypertensives recommend blood pressure monitoring in hypertensive patients. We measured the short-term effect of initiating NSAIDs on systolic blood pressure (SBP) in users of antihypertensives, aiming to investigate which outpatients are at risk for an increase in SBP in daily clinical practice.

Design: A cohort study with a nested case-control design in Dutch community pharmacies.

Methods: Patients with a drug-drug interaction alert for a newly initiated NSAID and antihypertensive were interviewed and their SBP was measured at T0, after one week (T1) and after two weeks (T2). We evaluated risk factors for exceeding a predefined limit of change (PLoC) in SBP (≥ 10 mmHg to ≥ 140 mmHg) at T1 and T2 versus T0.

Results: For 112 patients the SBP at T0 was measured. Two patients were excluded (T0 SBP ≥ 180 mmHg). PLoC was exceeded in 10 patients (10.4%) at T1 and in seven patients (8.0%) at T2. Patients using etoricoxib (odds ratio (OR), 21.0; 95% confidence interval (CI), 3.7-120.6) and patients using >1 defined daily dose of an NSAID (OR, 3.3; 95% CI, 1.1-10.0) were at increased risk of a rise in SBP.

Conclusions: A newly initiated NSAID has an immediate clinically relevant effect on SBP in some users of antihypertensives. Management guidelines for NSAID-antihypertensive drug-drug interactions should advise SBP monitoring before and after initiation of an NSAID or intensification of NSAID therapy. Monitoring is especially relevant in patients prescribed high dosages of NSAIDs. Etoricoxib should not be used in hypertensive patients.