Use of moxonidine in elderly patients with resistant hypertension

Background: Treatment of hypertension in the elderly people reduces the risk of cardiovascular and cerebrovascular events. Effective treatment often will require the use of two or more antihypertensive agents. Elderly people are at increased risk of adverse events from medication because of physiological changes in pharmacokinetics and pharmacodynamics, polypharmacy and drug interactions. They might not tolerate conventional add-on regimens of antihypertensives as a result. Objective: To investigate the use of the I-1-imidazoline receptor agonist moxonidine as an 'add-on' agent in elderly patients with resistant hypertension. Methods: We investigated the safety and efficacy of moxonidine (200-400 mu g) in a group of elderly patients whose blood pressure (BP) control remained poor despite treatment with two or more antihypertensives. BP was assessed by ambulatory BP monitoring with Spacelabs oscillometric equipment (Model 90207) before and after 6 weeks of treatment with moxonidine used as an 'add-on' agent with the patients normal medication. Results: Following treatment with moxonidine, the mean daytime systolic BP fell from 169.2 to 153.8 mmHg, a significant reduction of 15.4 +/- 8.9 mmHg (P = 0.003). The mean daytime diastolic BP fell from 91.6 to 84.2 mmHg, a reduction of 7.4 +/- 5.8 mmHg (P = 0.017). For the night-time readings, the systolic BP fell from 151.1 to 141.2 mmHg, a reduction of 9.3 +/- 9.3 mmHg (P = 0.05). The corresponding diastolic fall in BP was not significant (77.9-74.7 mmHg). The 24 h-readings showed a significant reduction in the mean systolic BP from 163.0 to 148.6 mmHg (P = 0.004). The mean diastolic BP also fell significantly from 87.2 to 80.2 mmHg (P = 0.013). Clinical BP readings also showed a significant reduction from 195.9 +/- 19.6 to 174 +/- 17.8 mmHg (P = 0.002) and 103.6 +/- 9.5 to 99.0 +/- 12.4 mmHg (P = 0.013) for systolic and diastolic readings respectively. Moxonidine was well tolerated in 11 of the14 patients. Conclusion: These results suggest that moxonidine might have a place as an 'add-on' treatment in elderly patients whose hypertension is poorly controlled despite treatment with two or more antihypertensive agents.