The Hypertension in the Very Elderly trial (HYVET), demonstrated the benefit of antihypertensive treatment in patients >or=80 years. However, patients in this age group are at increased risk of drug interactions and adverse effects. We conducted a retrospective cohort study, in hypertensive patients aged >or=80 years, to determine whether it is possible to follow the HYVET guidelines in an everyday clinical setting. We identified 100 patients aged >or=80 years referred to the Hypertension Clinic, University Hospital Birmingham, over a 10-year period. Most patients were referred to the clinic because of poorly controlled blood pressure despite treatment and all had 24 h ambulatory blood pressure monitoring (ABPM) as part of their assessment. All patients tolerated ABPM, and a 'white coat' effect was demonstrated in 33 patients. In 64 out of 100 patients (57 on treatment), the ABPM confirmed poor blood pressure control. Despite this, 26 of these patients had an antihypertensive either stopped (15), and /or reduced (3) or left unchanged (9) at clinic because of documented adverse drug reactions (ADRs). In 36 out of 100 patients, no additional antihypertensive therapy was needed because the blood pressure was either well-controlled on treatment (28), over-treated (4), or normotensive with a white coat effect (4). Despite this, antihypertensive agents were either stopped (10), and or reduced (5) because of ADRs in half the patients (14) from the well-controlled group. In conclusion, 40% patients had documented ADRs overall which limited further intervention, suggesting that implementation of the HYVET recommendations in clinical practice may be difficult.