Effect of antitubercular medications on blood pressure control in chronic kidney disease patients with tuberculosis: a prospective cohort study

Background: Previous anecdotal reports suggested a decrease in antihypertensive medication potency after starting antitubercular medications. This interaction could be unpredictable in presence of renal failure due to increased half-lives of most commonly used antihypertensive medications. Methods: In a cohort study involving 135 patients with chronic kidney disease (CKD), 62 patients with tuberculosis started on antitubercular medications (TB group) were prospectively compared with 73 CKD controls (with no TB and not on antitubercular medications) for a change in antihypertensive medications. Antihypertensive dose was converted to unit score. Results: The TB group had a greater increase in antihypertensive medication dose as compared with controls (89% vs. 54%, p < 0.0001). In absolute terms an overall increase in antihypertensive medications was observed in 60% of patients in the TB group, with a 2-fold dose increase from the baseline (p < 0.0001). Four patients from the TB group developed a hypertensive emergency. In multivariate linear regression, the association between TB group and increase in antihypertensives remained significant (beta = 0.38; p < 0.0001). Conclusions: In CKD patients, antihypertensive medication potency is reduced in TB patients on antitubercular therapy in a significant number of patients, to a clinically significant degree with a potential risk for hypertensive emergency.