Background: Non-steroidal anti-inflammatory drugs (NSAIDs) may increase blood pressure (BP) and blunt the effects of many antihypertensives. It seems that NSAIDs and the antihypertensive drugs differ in their propensity to such an interaction.
Objectives: To determine the extent of the interaction between two antihypertensives and three NSAIDs.
Methods: A prospective clinical trial in a family practice included 88 treated hypertensives aged over 55 years; 39 controls and 49, also taking NSAIDs for osteoarthritis. During this 3-month study, two antihypertensives, lisinopril/hydrochlorothiazide and amlodipine, were compared with three NSAIDs: ibuprofen, acetaminophen, and piroxicam. BP was measured with standard mercury sphygmomanometer and with an automatic device, in standing, sitting, and supine position.
Results: The average starting blood pressure in the study group was 149.3A+/-9.8/88.6A+/-6.8 mm Hg. In the lisinopril/hydrochlorothiazide subgroup, both ibuprofen and piroxicam elevated systolic BP by 7.7-9.9% (p<0.001), which, during the acetaminophen period, decreased by 6.9-9.4% to 0.3-0.9% above baseline (p<0.001), increasing again by 7.0-7.7% (p<0.001) during the second exposition to these drugs. In the amlodipine subgroup, ibuprofen or piroxicam increased BP by 1.1-1.6% (p>0.290) only, and there were no significant shifts in the follow-up periods. Analogous deviations were observed with both measurement devices, in all the examinee's positions. In the control group, BP did not change appreciably.
Conclusions: Piroxicam and ibuprofen markedly blunt the effects of antihypertensive drugs while acetaminophen is almost inert. Lisinopril/hydrochlorothiazide combination is much more affected by this interaction than amlodipine (ClinicalTrials.gov #NCT00631514).