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Prazosin was used as additional therapy in seven patients with severe chronic congestive cardiac failure. The effect on renal function in this situation was measured. Renal function improved in four of the seven patients, and this improvement was associated with improvement in their clinical condition; in two other patients, modest improvement in renal function was not associated with symptomatic relief which may have been the result of a gain in weight.

Prazosin has been used as an antihypertensive drug in the treatment of 93 patients in Dunedin since 1971-1972, mainly those whose previous control was unsatisfactory. It has led to very significant improvement of control in many cases; 48 patients now receiving the drug have taken it for an average of 30 months. Forty-five patients have stopped taking the drug for various reasons, such as failure to respond (11-8%), side effects (20-4%), myocardial infarction (8-6%) or unrelated reasons (7-5%). This reflects to some extent the use ofa new drug in patients who are difficult to control, and its use initially without concomitant diuretic and beta-blocker therapy. We believe that the place of praxosin is primarily as a third drug for patients whose hypertension does not respond satisfactorirly to a diuretic and a beta-blocker. The first dose must be kept small, preferably 0-25 mg, and even with this dose a small proportion of patients receiving diuretic and beta-blocker therapy seem to become hypotensive; patients should be warned about this. The plasma half-life in normal volunteers was 3-8 hours but in some patients it seems to be considerably longer.

Eight cases of postural focal cerebral ischaemia due to antihypertensive medications presented to one neurologist over an eight-month period. Most patients were elderly and suffered from chronic hypertension; their symptoms resolved after the reduction or cessation of these medications. These findings re-emphasize that considerable caution is required when antihypertensive medications are used in elderly persons and in patients with chronic hypertension whose cerebral blood-flow autoregulatory curves are shifted to the right. We also draw attention to the fact that drug-induced hypotension may induce focal cerebral ischaemia rather than generalized cerebral ischaemia more frequently than is generally appreciated.

Prazosin was used as an additional antihypertensive agent for treating 38 patients with hypertension and renal functional impairment. The drug was effective in 29 of these patients at a mean daily dose of 7 mg. The mean blood pressure fall in these 29 patients was 28/22 mm Hg. The most frequent (10 patients) and important side effect of prazosin treatment was dizziness, which occurred on standing of after exertion and was seen either after the first dose or after a large dose increase. The "first-dose phenomenon" was a result of severe postural hypotension and was eliminated by using a starting dose of 0-5 mg every 12 hours, with the first dose being given before retiring to bed. Dosage increments were limited to 0-5 mg, beginning late in the evening. Eleven patients had a significant improvement in renal function, while a further eight patients had stable renal function. In no patient was there a deterioration in renal function which could be attributed to prazosin.

The clinical usefulness of prazosin was investigated in 67 patients with mild to moderate essential hypertension for 6 to 12 weeks. The daily doses were increased from 3 to 9 mg according to the responses of the patients. The average reduction of mean arterial blood pressure by 6 weeks' prazosin treatment was 13-4 +/- 1-7 mm Hg. Thirty-three patients (49-3%) showed good or excellent responses to prazosin. Serious side effects or laboratory abnormalities did not appear in this trial, through postural dizziness was found in 6-0%. Prazosin seems to be a useful antihypertensive agent in the treatment of patients with mild or moderate essential hypertension.

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.

Minoxidil is very effective in the treatment of severe or resistant hypertension but fluid retention and hypertrichosis have been side-effects. This study examines the suggestion that the use of small doses of minoxidil may be effective in the treatment of moderate hypertension without causing these adverse effects. Sixteen patients with an elevated blood pressure level that was suboptimally controlled by combination therapy with diuretic and beta-adrenoreceptor blocking agents entered a randomized open trial to compare the efficacy and acceptability of minoxidil and prazosin as supplementary therapy to bendrofluazide and metoprolol. Blood pressure control was similar in the two groups. However, relatively large doses of minoxidil were required and over-all tolerance to the drug was poor; five of eight patients who were receiving minoxidil experienced marked fluid retention that necessitated a change in diuretic agent to substantial doses of frusemide. Low doses of minoxidil do not appear to be effective in the treatment of moderate hypertension, and the drug cannot be recommended for this indication.