Initial experience with prazosin in New Zealand. A multicentre report. New Zealand Hypertension Study Group.

Data are presented on 282 patients who began taking prazosin before March, 1975, and whose progress was followed until March, 1976. The following conclusions can be drawn. (i) Prazosin is an effective and useful antihypertensive agent, best used with a diuretic and a beta-blocker. (ii) For patients with suspected or definite coronary artery disease, prazosin should not be used without a beta-blocker. (iii) In patients suspected of having incipient heart failure, prazosin should not be used without a diuretic, and the latter should be given first. (iv) many patients have little or no rise in heart rate with prazosin. However, patients with sinus tachycardia or a history of arrhythmias should preferably not be treated with prazosin. (v) The initial dose should be kept small (0-25 to 0-5 mg). Subsequent increments should also be small, not more than 2 mg/day. (vi) If prazosin is added to a regimen containing an adrenergic neurone-blocking drug, the dose of the latter should first be reduced. (vii) Prazosin should not, in the meantime, be used concomitantly with a phenothiazine, as the combination appears to be capable of causing agitation and confusion. (viii) There seems to be no long-term toxicity.