Gene/Protein Disease Symptom Drug Enzyme Compound
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 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This paper reports the findings of an open evaluation of 100 patients treated with prazosin. When prazosin was added to existing hypotensive regimens in 50 patients whose blood pressure was poorly controlled, 36 (72 percent) became normotensive. Treatment was initiated with prazosin in a further 50 patients. Satisfactory control was achieved with prazosin alone in 24 and 20 of these became normotensive. The remaining 26 patients received in addition a beta-adrenoreceptor blocking agent together with a thiazide diuretic in 14. While prazosin alone caused a mean fall of 26/14mmHg in this group, the enchanced efficacy of combined therapy achieved a normal blood pressure in 19 (73 percent) and a total mean fall in pressure of 42/28mmHg. The most frequent side effect was dizziness or faintness at the start of therapy or, less often, when the dose was increased. This is minimised by using a low initial dose of 0.5mg two or three times daily. Prazosin is an effective hypotensive agent, used alone or in combination, in most patients with hypertension of all degrees of severity.
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PMID:Prazosin in hypertension. Part I. Clinical experience in 100 patients. 2 93

20 patients with severe essential hypertension (average blood-pressure 211/123 mm Hg) had an inadequate fall in blood-pressure with beta blockade alone. They were given in random order either 5 and then 10 mg of bendrofluazide a day or prazosin 2 mg three times daily rising to 5 mg if required. The trial was a within-patient comparison of the two drug regimens. 10 patients who did not achieve a satisfactory fall in pressure with either agent were then given all three drugs together. When bendrofluazide 5 or 10 mg was added to beta blockade there was an average fall in mean blood-pressure, standing, of 13%. When prazosin was added to beta blockade the average fall in mean blood-pressure, standing, was 16%. 18 patients who completed the trial had an average final blood-pressure, standing, of 139/93 mm Hg. In the prazosin period 8 patients continued to complain of dizziness after the first 24 h. With bendrofluazide serum-potassium levels fell below 3-6 mmol/l in half the patients within the first two weeks of treatment. It is concluded that patients with essential hypertension already treated with beta blockade who need an additional agent will get a further fall in blood-pressure with 5 mg of bendrofluazide. Prazosin appears to be a potent and appropriate third agent.
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PMID:Evaluation of beta blockade bendrofluazide, and prazosin in severe hypertension. 6 3

Twenty-two chronic hemodialysis patients with hypertension were treated with prazosin. Eight patients had volume-responsive hypertension, 11 volume-indpendent, and 3 high-renin hypertension. Blood pressure fell in all volume-responsive patients from a predialysis level of 175 +/- 5/100 +/- 3 to 148 +/- 4/75 +/- 3 mm Hg (p less than 0.001) after 3 months of therapy. Prazosin alone was effective in volume responsive patients at a dose of 5 +/- 1.0 mg daily. The blood pressure fell in volume-indpendent patients from 192 +/- 7/105 +/- 2 mm Hg predialysis to 155 +/- 6/80 +/- 3 after 3 months (p less than 0.001). Two were controlled on prazosin alone at a dose of 12 +/- 2 mg daily. Nine required 27 +/- 5 mg of prazosin daily as well as additional antihypertensive treatment. The blood pressure fell from 183 +/- 3/109 +/- 6 mm Hg predialysis to 173 +/- 17/85 +/- 3 mm Hg in high-renin patients after 3 months. One patient was controlled on 40 mg of prazosin daily. Two required 40 mg of prazosin daily as well as additional antihypertensive medication. Eleven patients described transient dizziness within the first month of therapy. One patient had recurrent syncope necessitating prazosin withdrawal; Prazosin is an effective antihypertensive agent which can be used in all types of hypertensive dialysis patients either alone or in combination with minimal side effects.
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PMID:Effects of prazosin in the control of blood pressure in hypertensive dialysis patients. 9 39

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.
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PMID:Open studies with prazosin in the treatment of essential hypertension. Prazosin Research Group in Japan. 91 32

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.
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PMID:Prazosin in the treatment of patients with hypertension and renal functional impairment. 91 33

Prazosin was used as an additional antihypertensive agent for treating 16 patients with hypertension and significant renal functional impairment. The drug was effective in 13 patients at a mean daily dose of 7.9 mg. The most important side effect of prazosin treatment was dizziness which occurred on standing or following exertion, and was seen either after the first dose or following a large increase in dose. This could be prevented by giving the very first dose of 0.5 mg late in the evening. Five patients complained of palpitations. In no patient was there a deterioration in renal function which could be attributed to prazosin. Five women had a significant improvement in renal function.
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PMID:Prazosin in the treatment of patients with hypertension and renal functional impairment. 107 80

This randomized double-blind crossover trial was conducted to assess the effects of prazosin, an alpha 1-adrenoceptor blocking drug, on the voiding of 35 patients with benign prostatic obstruction. Maximum and mean flow rates, residual urine, blood pressure and heart rate were measured at baseline and 2, 4, 6, and 8 weeks after starting the treatment with placebo or prazosin. At 4 weeks the treatments were switched over. The patients filled micturition charts at home and scored their voiding associated feelings. The maximum and mean flow rates increased significantly during prazosin treatment, as also did the maximum and mean voided volumes. Residual urine decreased and voiding improved subjectively but these changes were not statistically significant. Blood pressure was lowered and heart rate increased. Prazosin caused postural dizziness more often than placebo. Prazosin seems to offer an alternative to improve voiding in some patients with prostatic obstruction.
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PMID:Efficacy and side-effects of prazosin as a symptomatic treatment of benign prostatic obstruction. 171 Aug 23

Isradipine is a dihydropyridine calcium-entry blocking agent with pronounced vasodilator activity and no significant cardiac effects at clinical doses, a desirable profile for an antihypertensive drug. Prazosin, a post-junctional alpha-adrenoceptor blocking agent, may produce a similar hemodynamic pattern. Therefore, we compared the effects of isradipine (2.5-10 mg bid) with those of prazosin (2-8 mg bid) in 83 patients with established essential hypertension, using a randomized, double-blind, parallel-group design. Patients received a placebo for 3-5 weeks, then either isradipine or prazosin over a 6-week titration period, followed by a 4-week plateau phase. During the plateau period, isradipine therapy lowered sitting blood pressure more effectively than did the administration of prazosin: Mean systolic BP fell 16.7 versus 8.1 mmHg (p less than 0.001) and mean diastolic BP was reduced 15.6 versus 12.6 mmHg (p less than 0.01). In the dosing range used (while also noting that prazosin is occasionally titrated up to doses of 30 mg qd), 83% of isradipine-treated patients had at least a 10 mmHg reduction in diastolic BP, compared with 64% of prazosin-treated patients (p = 0.05, FET). Tachyphylaxis did not occur with either drug. The rate of occurrence of side effects was similar in both treatment groups; the most common adverse event seen with isradipine was headache (20%) and with prazosin, dizziness (19%).
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PMID:A multicenter comparison of isradipine and prazosin for treatment of essential hypertension. 214 12

Prazosin and terazosin are two alpha 1-adrenoceptor blocking agents, their principal difference being the longer half-life of terazosin. The present study was carried out to determine if elderly subjects are different from the young in their pharmacokinetic handling of these two drugs and if age influences the blood pressure response to each drug. Ten young healthy subjects (aged 19-30 years) and five older healthy subjects (aged 54-62 years) received 1 or 2 mg terazosin, 1 or 2 mg prazosin, or placebo 1 week apart according to a 5 X 5 Latin square design. Concentrations of prazosin and terazosin were measured using a high-performance liquid chromatographic procedure with a detection limit of approximately 0.25 ng/ml. Pharmacokinetic parameters of prazosin were virtually the same in both groups, whereas mean terazosin plasma concentrations were higher in the older group and pharmacokinetic analysis revealed higher peak plasma concentrations and a longer terminal elimination half-life. There was no evidence of increased sensitivity to the hypotensive action of the drug, as peak upright blood pressure falls were similar in the two groups. Symptoms of dizziness in the upright position were also less common. In view of their lack of sedative effects and minimal metabolic disturbances, further studies should be conducted to assess the suitability of these drugs as monotherapy for hypertension in elderly patients.
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PMID:Effect of age on pharmacokinetics of and blood pressure responses to prazosin and terazosin. 244 Nov 67

Selective alpha 1 adrenergic receptor blocking agents lower blood pressure by reducing the increased peripheral vascular resistance that characterizes essential hypertension. Prazosin and terazosin have been shown to be well tolerated in clinical practice and seldom cause impotence or metabolic abnormalities. The most common adverse effects--dizziness, headache, and asthenia--are generally well tolerated and infrequently lead to discontinuation of therapy. First-dose syncope can usually be avoided by initiating therapy with low doses administered at bedtime. Finally, the alpha 1 receptor antagonists do not adversely affect such cardiovascular risk factors as hypokalemia, serum lipid profile, and left ventricular hypertrophy. In fact, alpha 1 antagonists reduce total cholesterol and low-density-lipoprotein plus very-low-density-lipoprotein cholesterol and thus may contribute to the overall management of cardiovascular risk by blood pressure reduction and improvement of the serum lipid profile. Since the goal of treating chronic essential hypertension is to improve morbidity and mortality, the choice of therapy should be influenced by the agent's ability to modify as many risk factors as possible. Alpha 1 adrenoreceptor antagonists beneficially impact several cardiovascular risk factors and thus merit consideration as first-line antihypertensive therapy.
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PMID:New perspectives on selective alpha 1 blockade. 257 43


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