Endocrine Abstracts

The vasodilator minoxidil is a potent antihypertensive agent. However, its use has been rather limited and it can easily be overlooked in the era of ACE inhibition and angiotensin receptor blockade. It must be used with diuretic and beta-blocker cover.

We reviewed 13 male patients with refractory hypertension attending our hypertension clinic from January to July 2004 and currently receiving minoxidil. Analysis was with paired t-tests.

Median age was 55 years and mean hypertension duration 11.3 (plus/minus 3.4) years (95% confidence interval). All were receiving diuretic therapy and beta-blockers prior to minoxidil therapy. Twelve were also receiving either an ACE inhibitor or angiotensin II receptor antagonist at initiation. The mean number of anti-hypertensive agents was 4 prior to minoxidil and mean blood pressure prior to its initiation was 174/103 (plus/minus 10/7) mmHg. At 2 and 6 months this had fallen to 150/88 (plus/minus 12/6) and 148/87 (plus/minus 12/8), both p<0.01, compared to baseline. Blood pressure of <140 and <90 was achieved in 6 of 10 patients followed to 6 months and these 6, compared to none at baseline, achieved audit standard targets (British Hypertension Society IV, 2004). No patients developed side effects, such as tachycardia, heart failure or hypertrichosis. Three patients developed oedema, which resolved with increased diuretic dose. Serum creatinine was unchanged. Mean minoxidil dose in milligrams was 9.4 at 1 week after commencement and 17.5 and 16.8 at 2 and 6 months respectively.

Minoxidil is effective in refractory hypertension. Potentially severe side effects can be controlled by beta-blockers, diuretics, careful dose titration and intensive early follow up. We believe it should be used more in refractory hypertension.