Purpose: Non-steroidal anti-inflammatory drugs (NSAIDs) are known to antagonize the effects of antihypertensive drugs, and these associations can lead to an increase in arterial blood pressure. However, the impact of NSAIDs on hypertension treatment management in large-scale populations remains poorly evaluated. We examined whether the introduction of NSAID into the treatment regimen would induce an intensification of hypertension treatment (defined as the introduction of a new antihypertensive drug). Methods: We conducted a cohort study involving 5,710 hypertensive subjects included in the French health insurance system database who had been treated and stabilized with their antihypertensive therapy and not exposed to any NSAID between 1 April 2005 and 1 April 2006. The maximum follow-up duration was 4 years. Results: Adjusted hazard ratios (HR) for hypertension treatment intensification were 1.34 [95 % confidence interval (CI) 1.05-1.71] for NSAIDs in general, 1.79 (95 % CI 1.15-2.78) for diclofenac and 2.02 (95 % CI:1.09-3.77) for piroxicam. There were significant interactions between NSAIDs and angiotensin converting enzyme inhibitors (ACEIs; HR 4.09, 95 % CI 2.02-8.27) or angiotensin receptor blockers (ARBs; HR 3.62, 95 % CI 1.80-7.31), but not with other antihypertensive drugs. Conclusions: Exposure to NSAIDs leads to an intensification of hypertension treatment, especially in patients treated with ACEIs or ARBs. Renin-angiotensin system blockers should be avoided whenever NSAIDs are prescribed.