Abstract
Background Epidemiological evidence suggests an indirect link between hypertension and tuberculosis, and several studies have reported that rifampicin has potentially diminished the hypotensive effects of many anti-hypertensive agents by inducing cytochrome P450. This study investigates rifampicin's effect on the target blood pressure in known hypertensive patients whose blood pressure had been previously controlled with anti-hypertensive drugs. Methodology This prospective observational study was conducted at the Institute of Internal Medicine, Madras Medical College and Rajiv Gandhi Government General Hospital, Chennai, from June 2021 to December 2022. A total of 160 patients with known hypertension on anti-hypertensive drugs were recruited for this study. All these patients had been recently diagnosed with tuberculosis and had been treated with rifampicin-based anti-tuberculosis therapy (ATT). Results The maximum number of patients were under 50 years of age and predominantly male (67%). A total of 91 (57%) patients were hypertensive for less than five years, and the remaining patients were hypertensive within 6-10 years or more than 10 years. However, these patients had other comorbidities such as diabetes mellitus (32%) and coronary artery disease (27%). Before ATT, the mean systolic blood pressure (SBP)/diastolic blood pressure (DBP) was recorded to be 130/80 mmHg. The last six months' course of ATT showed mean values around 154/96 mmHg even after adding additional/multiple anti-hypertensive drugs. After discontinuation of ATT, the mean SBP/DBP was effectively 130/80 mmHg at four weeks. Conclusions Rifampicin significantly diminishes the hypotensive effects of many well-established anti-hypertensives such as calcium channel blockers, beta-blockers, and diuretics to maintain blood pressure.