Exposição a interações medicamentosas de pacientes com hipertensão resistente e pseudorresistente: um estudo caso-controle

Abstract

Background: Resistant hypertension is the condition in which blood pressure remains uncontrolled (BP ≥ 140/90 mmHg) even with the use of three antihypertensive drugs synergistically, and preferably a diuretic in adequate doses. Diagnosis is often overestimated, given that some confounding factors aren’t considered, as inadequate blood pressure measurement, white-coat effect, poor adherence and therapeutic inadequacy, which lead us to pseudoresistance. Another factor to consider is the possible occurrence of drug interactions, defined as the result of interference in the effect of a drug by another drug, eminent among hypertensive patients taking antihypertensive drugs and drugs for the treatment of comorbidity. Drug interactions sometimes reduce the efficiency of anti-hypertensive, leading to blood pressure uncontrolled. Objective: To evaluate the relationship between exposure to drug interactions of reduction of the effectiveness of antihypertensive treatment and the occurrence of resistant hypertension and pseudoresistant hypertension. Methods: This is a case-control study with hypertensive patients assisted at the Hospital University Professor Alberto Antunes, in the city Maceió. Two pairs of comparison were structured, one among patients with resistant hypertension (cases-1) and hypertensive patients with controlled blood pressure, with similar characteristics (controls), and another between patients with pseudoresistant hypertension (cases-2) and controls, in a ratio of 1 : 4. Blood pressure measurements were performed, patients with resistance characteristics were submitted to ambulatory blood pressure monitoring, in order to exclude the effect of white-coat. Excluding confounding factors, patients were evaluated by a cardiologist who gave the diagnosis of resistant hypertension. The data was collected through questionnaire to obtain sociodemographic data, medication use and adherence. Potential drug interactions were identified through the Micromedex Healthcare Series software and manifest drug interactions through clinical data and confirmation with supporting literature. Results: 17 (6.9%) patients were resistant (cases-1) and 102 (41.3%) were pseudoresistant (cases-2), both were compared to 128 (51.8%) patients with controlled blood pressure and similar characteristics (controls). Among the resistant, 5 (41.7%) patients evidenced potential drug interaction of reduction the antihypertensive efficiency, of which 100% manifested, different from the control group that didn’t present this type of interaction. Among the pseudoresistant, 48 (80.0%) patients evidenced potential drug interaction of reduction the antihypertensive efficiency, of which 100% manifested, different from the control group that didn’t present this type of interaction. Conclusion: The occurrence of drug interactions among resistant hypertensives may be a confusion factor, because may suggest resistance, when the patients should be pseudoresistant, necessitating the cessation of drug interactions to confirm the diagnosis of resistant hypertension.