Concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs), including the cyclooxygenase-2 (COX-2) specific inhibitors, with antihypertensive medication is common practice for many patients with arthritis. This study evaluated the effects of celecoxib 200 mg/day and rofecoxib 25 mg/day on blood pressure (BP) and edema in a 6-week, randomized, parallel-group, double-blind study in patients > or =65 years of age with osteoarthritis who were treated with fixed antihypertensive regimens. One thousand ninety-two patients received study medication (celecoxib, n = 549; rofecoxib, n = 543). Significantly more patients in the rofecoxib group compared with the celecoxib group developed increased systolic BP (change >20 mm Hg plus absolute value > or =140 mm Hg) at any time point (14.9% vs 6.9%, p <0.01). Rofecoxib caused the greatest increase in systolic BP in patients receiving angiotensin-converting enzyme inhibitors or beta blockers, whereas those on calcium channel antagonists or diuretic monotherapy receiving either celecoxib or rofecoxib showed no significant increases in BP. Clinically significant new-onset or worsening edema associated with weight gain developed in a greater percentage of patients in the rofecoxib group (7.7%) compared with the celecoxib group (4.7%) (p <0.05). Thus, in patients with controlled hypertension on a fixed antihypertensive regimen, careful monitoring of BP is warranted after the initiation of celecoxib or rofecoxib therapy.