What to do when blood pressure is difficult to control

There is no universally accepted definition of blood pressure that is difficult to control, uncontrolled, resistant, or refractory. One consensus based US national guideline defines resistant hypertension as blood pressure that cannot be reduced below 140/90 mm Hg (below 160 mm Hg for isolated systolic hypertension) in patients who are complying with adequate triple drug regimens in appropriate dosage.1 This definition covers many hypertensive patients but not those for whom the target is an even lower pressure. #### Summary points Consider the following causes for apparently resistant blood pressure: inaccurate measurement, antagonising substances such as non-steroidal anti-inflammatory drugs, aggravating conditions such as obesity or sleep apnoea, suboptimal treatment regimens, non-compliance When apparent resistance remains unexplained or when there are clues suggesting white coat hypertension, consider this and arrange for multiple measurements by self monitoring, visits to or by nurses or health visitors, or ambulatory monitoring If hypertension is still unexplained, or for patients who fit specific patterns of higher risk, consider a selective, sequential evaluation for secondary causes of hypertension, starting with relatively common conditions, such as renovascular causes and renal parenchymal disease Work closely with patients to identify preferred and feasible solutions for correcting any cause that is found Consider referral of patients with severe or persistently resistant hypertension to a centre specialising in its diagnosis and treatment Both clinical experience and research surveys suggest that resistant blood pressure is common in everyday practice. For example, population and clinic surveys in North America, Europe, and Australia show that in as many as 50% to 75% of people being treated for hypertension target blood pressure levels are not achieved.2 Fifty per cent of the 19 196 participants in one recent trial had uncontrolled blood pressure levels when enrolled despite already being treated for hypertension; 59% of these uncontrolled patients were being …