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At least 19 recordsLinked to original sources
PubMed1976

Studies with prazosin--a new effective hypotensive agent. I. Open clinical study of prazosin in combination with other antihypertensive agents.

The use of prazosin, a new antihypertensive agent, in combination with other conventional antihypertensive agents, in a hospital outpatient clinic setting, was studied in a mixed group of 104 hypertensive patients. Prazosin effectively lowered the lying and standing blood pressure in the majority of patients whose blood pressure was uncontrolled or poorly controlled before the introduction of prazosin. Blood pressure control was adequately maintained in patients who were given prazosin because of the occurrence of side effects of other antihypertensive medication. No significant change in renal function attributable to prazosin was found in patients with normal or impaired renal function.

Adult↗
PubMed1978

Propranolol as an antihypertensive agent in children.

The antihypertensive effect of oral propranolol was studied in 9 children with hypertension. After treatment with propranolol, systolic blood pressure fell by an average of 26 mmHg (P less than 0.01). Diastolic pressure decreased by 20 mmHg on average (P less than 0.01). The mean propranolol dose was 2.5 mg/kg per day. Side effects included bradycardia and anorexia. There was no correlation between pretreatment plasma renin activity and fall in blood pressure. Propranolol is an effective and well tolerated antihypertensive agent in children.

Adolescent↗
PubMedDate not supplied

Reactivity of normotensive and spontaneously hypertensive rats (SHR) to some antihypertensive agents after acute and chronic treatment.

Hypotensive action of some antihypertensive agents was studied on normotensive and spontaneously hypertensive rats in acute and chronic treatment. The reactivity of normotensive rats was much more weaker than in rats with spontaneous hypertension (SHR). Results of the experiments indicate also that the selection of new antihypertensive agents should be based on tests carried out with at least two models of hypertension.

Animals↗
PubMed1977

Preventing, detecting and managing adverse reactions of antihypertensive agents in the ambulant patient with essential hypertension.

The adverse reactions of antihypertensive agents are reviewed, including their clinical implications and suggested methods of preventing, detecting and managing them. The drugs discussed are: (1) diuretics--thiazides, furosemide, ethacrynic acid and spironolactone; (2) sympatholytics--reserpine, methyldopa, guanethidine, propranolol and clonidine; (3) vasodilators--hydralazine, prazosin and minoxidil. It is suggested that cooperative multi-disciplinary efforts should be undertaken to counteract the factors which contribute to improper use of antihypertensive agents.

Antihypertensive Agents↗
PubMed1978

Anaesthetised normotensive rats for the detection of hypotensive activity of a beta-adrenoceptor antagonist and other antihypertensive agents.

A simple method for the detection of antihypertensive activity in anaesthetised (66 mg/kg i. v. alpha-chloralose and 20 mg/kg i. v. aprobarbital) normotensive rats is described. Dihydralazine (0.5 to 2 mg/kg i. v.) reduced blood pressure dose-dependently but did not provoke the anticipated tachycardia. Clonidine (1 to 8 microgram/kg i.a.), guanethidine (0.5 to 5 mg/kg i.a.) and alpha-methyldopa (2.5 to 10 mg/kg i.a.) reduced blood pressure dose-dependently; the effect of reserpine (0.1 to 1.0 mg/kg i.a) was, however, not dose-dependent. Although all four drugs reduced heart rate, only clonidine and guanethidine did so in a dose-dependent manner. Phentolamine (0.5 to 2 mg/kg i. v.) and propranolol (0.01 to 1 mg/kg i. v.) elicited dose-dependent falls in blood pressure. Whereas phentolamine increased heart-rate slightly, propranolol elicited a bradycardia. It is concluded that the chloralose-aprobarbital anaesthetised rat is a suitable and economical model for the screening of potential antihypertensive agents including beta-adrenoceptor antagonists. However, reflex trachycardia provoked by peripheral vasodilators may not be apparent.

Adrenergic beta-Antagonists↗
PubMed1977

Physiologic evaluation of a new antihypertensive agent: prazosin HCl.

The mechanism of action of prazosin hydrochloride, a new antihypertensive agent was studied in 14 patients with essential hypertension. Mean supine blood pressure for the group fell from 148/102 +/- 3/2 (SE) mm Hg at baseline to 139/91 +/- 5/4 after eight weeks of therapy (P less than 0.05). No significant postural hypotension was noted in the patients who responded to therapy. Glomerular filtration rate (endogenous creatinine or inulin clearance) and effective renal plasma flow (PAH clearance) remained unchanged during therapy as did supine and stimulated peripheral plasma renin activity. Cardiac output did not change significantly although plasma volume increased in ten out of 12 patients in whom it was measured (P less than 0.025). Among the patients whose mean blood pressure fell 10 mm Hg or more, peripheral vascular resistance fell significantly (P less than 0.025), and the change in plasma volume was not statistically significant. Among the patients whose mean blood pressure changed less than 10 mm Hg with therapy, there was no significant change in peripheral vascular resistance and plasma volume increased significantly (P less than 0.025). Prazosin hydrochloride appears to be an effective antihypertensive agent which acts by peripheral vasodilatation. It may cause fluid retention. The drug does not appear to affect renal function or renin secretion.

Adult↗
PubMed1978

[Hemodynamics and metabolic parameters during use of the antihypertensive agent diazoxide].

The antihypertensive remedy diazoxide (hyperstat) was applied in 11 patients with hypertension of the clinical stages III and IV. The patients were applied a single intravenous injection of 20 ml = 300 mg diazoxide. The behaviour of blood pressure, pulse, blood sugar and cortisol level as well as of the blood supply in rest of the musculature of the extremities was tested and evaluated. Within 1 minute after the injection the systolic blood pressure decreased by 12%, the diastolic by 20%. After an above all show increase of the diastolic blood pressure once more a slight decrease of the systolic blood pressure followed after 90 minutes, which lasted several hours. Also after 24 hours the blood pressure did not reach the original value. The increase of the pulse rate was clinically not relevant. The blood glucose increased in the 5th minute, after 15 minutes it reached its culmination point and, beginning with the 30th minute it showed a decreasing tendency. The initial values were got after 180 minutes. After the 15th minute began a relative short-term decrease of the plasma cortisol, which, however, again increased after 60 minutes. On the other hand the occlusion-plethysmographic investigations of the veins showed an increasing blood flow in rest up to 3 hours after the injection.

Adult↗
PubMed1977

[Interaction between antihypertensive agents and psychotropic drugs (author's transl)].

The present review paper is dealing with the interaction between antihypertensive agents and various psychotropic drugs. Various psychotropic drugs enhance certain-side-effects of the antihypertensive substances, like sedation, extrapyramidal disorders and orthostatic hypotension. On the other hand, the blood-pressure lowering effect of clonidine, guanethidine and related drugs, and possibly also that of alpha-methy-dopa is reduced by phenothiazine-neuroleptics and tricyclic antidepressants (thymoleptics), but not by benzodiazepine tranquilizers or by butyrophenone-like neuroleptics. The pharmacological background and the clinical relevance of these interaction phenomena are discussed.

Antihypertensive Agents↗
PubMed1977

Increased pulmonary vascular resistance with systemic hypertension. Effect of minoxidil and other antihypertensive agents.

Recent case reports suggest that pulmonary hypertension could be caused by minoxidil, a new potent vasodilating antihypertensive drug. Therefore, we evaluated the incidence and severity of pulmonary hypertension in 110 patients with systemic hypertension. Fourteen patients were treated with minoxidil for 2 to 35 months (mean 19.9 months), 15 were treated with no drugs, and the remaining 81 patients received conventional antihypertensive agents of several types. Pulmonary vascular resistance correlated positively (P is less than 0.05) with systemic vascular resistance. Minoxidil-treated patients with hypertension previously refractory to conventional therapy had slightly lower pulmonary vascular resistance than other hypertensive subjects. There was no correlation between pulmonary vascular resistance and duration of minoxidil therapy or other types of antihypertensive regimens. The positive correlation between pulmonary and systemic vascular resistance suggests the possibility of a causal hypertension relation in the two vascular beds.

Adolescent↗
PubMed1977

The regional localisation of a new potent centrally acting antihypertensive agent R 28935 and its less active threo-isomer R29814 in the cat brain.

Systemic administration of the centrally acting antihypertensive agent R 28935 to cats resulted in a long lasting decrease of mean arterial pressure (+/-30%) whereas the same dose of the threo-isomer R 29814 was ineffective. The antihypertensive activity was due to the unaltered drug. In spite of an identical log P, pKa, dose and a comparable plasma level, the concentration of R 28935 in all the brain areas tested was about twice that of the threo-isomer, suggesting a stereoselective uptake and/or binding of R 28935.

Animals↗
PubMed1977

Conformational analogues of antihypertensive agents related to guanethidine.

In an effort to clarify the conformational requirements, if any, of agents producing adrenergic neuronal blockade through mechanisms similar to guanethidine, the synthesis and pharmacological evaluation of 15 analogues of cinnamylguanidine are described. These analogues represent derivatives in which the distance between the center of the ring system and the guanidinium nitrogen atom varies from 3.9 to 6.2 A. While conformational relationships could not be defined in this study, three analogues (3, 4, and 5) were apparently more potent than guanethidine in the in vitro assay employed.

Adrenergic Agents↗
PubMed1977

BRL 13776: a novel antihypertensive agent with interesting monoamine depleting properties.

1. Oral doses of 10-100 mg/kg of BRL 13776 lowered the blood pressure of both deoxycorticosterone acetate (DOCA)/NaCl-treated hypertensive rats and untreated normotensive rats. 2. BRL 13776 (100 mg/kg, orally) also reduced the blood pressure of renal hypertensive cats (cellophane perinephritis model). 3. No tolerance developed to the blood-pressure lowering action of BRL 13776 when an oral daily dose of 100 mg/kg was administered repeatedly for up to 15 days to hypertensive rats and cats. 4. The fall in blood pressure to BRL 13776 in rats was associated with a reduction of tissue catecholamines. 5. The catecholamine depletion occurred in all the peripheral tissues examined but in the brain was restricted to certain regions, these being the hind-brain on single dosing and the hind-brain, hypothalamus and mid-brain on repeated dosing. Catecholamine levels in the cerebral hemispheres were not affected by either single or repeated doses of BRL 13776. 6. BRL 13776 caused some reduction of the 5-hydroxytryptamine content of the heart but not of whole brain or any brain region. 7. Neither single doses (up to 900 mg/kg orally) nor repeated doses (100-300 mg/kg orally) of BRL 13776 produced any significant behavioural effects in animals. 8. BRL 13776 is a new type of agent to display both antihypertensive and monoamine-depleting properties. The reduction of noradrenaline in certain brain regions may be a cause of the antihypertensive response but depletion in the periphery could contribute in a major or minor way. The differential action on noradrenaline in the brain together with the lack of effect on 5-hydroxytryptamine might also explain the apparent absence of behavioural effects.

Animals↗
PubMed1977

[Synthesis and physico-chemical properties of the antihypertensive agent urapidil (author's transl)].

6-(3-[4-(o-Methoxyphenyl)-1-piperazinyl]-propylamino)-1,3-dimethyluracil (Urapidil, Ebrantil) is a new antihypertensive agent whose synthesis and physico-chemical properties are described. The size of the permeation constant KD of the passive transport through collodion-lecithin membranes and the value of the partition coefficient P in the neutral area indicate a good absorption and uniform distribution of the substance in the organism.

Antihypertensive Agents↗