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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Despite the importance of pregnancy-induced hypertension (PIH), there are few published investigations of therapeutic approaches for the postpartum management of such patients. Twenty-six gravida patients with PIH were prospectively studied during the first 24 hours after delivery while receiving intravenous magnesium sulfate. Each study subject was randomly assigned to a group also systemically administered either hydralazine or methyldopa. During the study interval, hourly measurements of blood pressure, pulse, fluid intake, and urine output were recorded. Hydralazine was found to be superior in its ability to effect more rapidly a lower mean arterial blood pressure. No significant differences in urine output or time until onset of diuresis were noted among treatment groups. No serious side effects were encountered with the use of either antihypertensive agent. Based on these preliminary findings, it appears that hydralazine is the less costly and more effective medication to lower mean arterial blood pressure in the immediate postpartum period.
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PMID:Utilization of hydralazine or alpha-methyldopa for the management of early puerperal hypertension. 278 42

In a double-blind, randomized, crossover study, the effects of intravenous pinacidil, 0.2 mg/kg, were compared with those of hydralazine, 0.3 mg/kg, before and after beta-adrenoceptor blockade in six subjects with hypertension. Both drugs equally reduced total peripheral resistance by about 40%. Pinacidil reduced mean blood pressure by an average of 30 mm Hg, while the reduction after hydralazine was 10 mm Hg. The difference in antihypertensive effect resulted from greater increases in heart rate, cardiac contractility (systolic time intervals), and cardiac index (thermodilution) after hydralazine. These effects after hydralazine could not be fully abolished by beta-blockade, as could the effects after pinacidil. Pinacidil decreased pulmonary blood pressure, whereas there was a slight rise in pulmonary blood pressure after hydralazine. Forearm blood flow (venous occlusion strain gauge plethysmography) increased equally after both drugs; thus pinacidil decreased forearm vascular resistance more than hydralazine did. Serum concentrations of both drugs were within the therapeutic range and correlated with the fall in mean blood pressure. Five subjects complained of side effects after hydralazine, but none were reported after pinacidil. Hydralazine increased myocardial oxygen consumption (as estimated from the rate-pressure product) by 35%; there was no change after pinacidil. It is suggested that hydralazine has direct cardiostimulatory effects that limit its antihypertensive effectiveness. These effects increase myocardial oxygen consumption and may be responsible for the common and sometimes severe cardiovascular side effects of hydralazine.
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PMID:Acute hemodynamic effects of pinacidil and hydralazine in essential hypertension. 285 1

The management of common medical problems in pregnancy often requires adjustments in drug therapy to assure a healthy fetus. The management of steroid-dependent bronchial asthma in pregnancy requires oxygen supplementation as well as vigorous treatment of airway obstruction to protect the fetus from maternal hypoxemia. The hypertensive pregnant patient should discontinue dietary sodium restriction and diuretic therapy and should be managed with alphmethyldopa or beta-blocker therapy. Hydralazine may be added if hypertension is severe. Mitral valve prolapse appears to produce no difficulties during pregnancy and the use of prophylactic antibiotics is probably not necessary for routine vaginal delivery, unless complications occur. Digoxin and quinidine are safe to use in pregnancy, provided careful monitoring is maintained. Oral anticoagulants are contraindicated in pregnancy and should be replaced with heparin if pregnancy is desired.
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PMID:Cardiovascular and respiratory agents during pregnancy: implications for fetal development. 286 59

New England Deaconness Hospital rats harboring a transplantable pheochromocytoma exhibit plasma norepinephrine concentrations 20-fold higher than controls. A cardiomyopathy (CM) characterized by multifocal areas of interstitial and replacement fibrosis, mixed inflammatory infiltrates and contraction band necrosis is evident 35 to 45 days after tumor implantation. Using a morphological scoring system of 0 (no cardiac damage) to 3 (involvement of almost the complete ventricular cross-section sampled), a CM score of 1.8 +/- 0.1 was found in rats harboring pheochromocytoma, a significant increase over that in age- and sex-matched controls (0.4 +/- 0.1, P less than .001). The pheochromocytoma rats also had hypertension (systolic blood pressure = 182 +/- 4 vs. 131 +/- 2 mm Hg in controls, P less than .001). In an effort to prevent the CM, rats harboring pheochromocytoma were treated with either the beta receptor antagonist timolol, the alpha receptor antagonists phentolamine or phenoxybenzamine or the nonspecific vasodilator hydralazine. Hydralazine normalized systolic blood pressure (135 +/- 6 mm Hg), whereas timolol (144 +/- 5 mm Hg), phenoxybenzamine (166 +/- 5 mm Hg) or phentolamine (154 +/- 10 mm Hg) only moderately decreased blood pressure in rats harboring pheochromocytoma. Hydralazine had no effect on CM score (1.8 +/- 0.1). Timolol markedly attenuated the CM score (0.6 +/- 0.1), whereas the alpha adrenergic antagonists were not as effective (phenoxybenzamine CM score = 1.3 +/- 0.2; phentolamine CM score = 1.7 +/- 0.2). Furthermore, timolol prevented desensitization of beta adrenergic receptor-mediated contraction in the hearts of rats harboring pheochromocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of adrenergic receptor antagonists on cardiac morphological and functional alterations in rats harboring pheochromocytoma. 288 96

During 1983, 38 patients with pregnancy-induced hypertension were treated with hydralazine-apresoline (1-hydrazinophthalazine). During the course of their treatment, five of these patients showed evidence of the HELLP syndrome described by Weinstein (hemolysis, thrombocytopenia, and elevated liver enzymes). Evidence is presented on the role of hydralazine in producing hepatocellular damage. Liver function is compromised during the natural course of pregnancy-induced hypertension, and 5-10% of preeclamptic patients develop the HELLP syndrome. In many places hydralazine is the drug of choice in the treatment of pregnancy-induced hypertension.
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PMID:Hydralazine-induced hepatitis in pregnancy. 289 36

The purpose of these studies was to evaluate structural and functional changes in a model of hypertension-induced cardiac hypertrophy in which vasodilator therapy prevented the increase in blood pressure. Uninephrectomized weanling (125 g) Sprague-Dawley rats received a Silastic implant containing deoxycorticosterone acetate (DOCA, 150 mg/kg) subcutaneously and were given drinking water containing sodium chloride and potassium chloride. Vasodilator antihypertensive treatment (hydralazine; HYD) was started immediately after DOCA implantation. The rise in blood pressure was prevented in DOCA + HYD (124 +/- 5.4 mm Hg, +/- S.E.M.) compared to DOCA (213 +/- 7.5 mm Hg), and blood pressure was not different from control (CON; 118 +/- 5.5 mm Hg). Hydralazine lowered blood pressure in CON + HYD (102 + 3.9 mm Hg) but this decrease was not significant (P greater than 0.05). Hydralazine treatment prevented hypertension in DOCA + HYD but did not prevent development of cardiac hypertrophy (heart weight/body weight of DOCA + HYD 3.99 +/- 0.1 vs. DOCA 4.15 +/- 0.1; CON, 3.23 +/- 0.2 and CON + HYD 3.27 +/- 0.1). Coronary flow reserve measured by adenosine vasodilatation in a modified Langendorff isolated perfused rat heart model, was decreased in hearts from DOCA rats (41% increase in flow above baseline) compared to controls (CON, 132%; CON + HYD 139%), and was significantly improved in DOCA + HYD (98%). Morphometric evaluation of perfusion-fixed coronary arteries demonstrated a significant increase in the slope of the regression line comparing the square root of medial area vs. outer diameter in DOCA (0.619) compared to CON (0.501) and CON + HYD (0.491). Blood vessels from DOCA + HYD were not different from control (0.503). These studies suggest that significant alterations in coronary vascular structure and function occur in hypertension-induced cardiac hypertrophy. The coronary vasculature is responsive to blood pressure, independent of cardiac hypertrophy, although coronary deficits do remain after antihypertensive therapy.
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PMID:Coronary vascular function and morphology in hydralazine treated DOCA salt rats. 297 41

The response of renin release to the administration of renin inhibitors cannot be studied with conventional enzymatic methods used to measure plasma renin. In the present experiments, a novel multirange enzyme-linked immunosorbent assay for human and primate renin was used to investigate the changes in plasma immunoreactive renin after renin inhibition. A potent and long-acting statine-containing renin inhibitor, CGP 29 287, was injected in conscious marmosets after mild or severe sodium depletion. In mildly sodium-depleted marmosets, CGP 29 287 (0.1 mg/kg i.v.) reduced mean arterial blood pressure and completely inhibited plasma renin activity for up to 30 minutes. This response was associated with a transient increase in plasma immunoreactive renin concentration. After a dose of 1.0 mg/kg i.v., the reduction of mean arterial pressure and the complete inhibition of plasma renin activity persisted for up to 120 minutes. These effects were accompanied by a sustained increase in plasma immunoreactive renin concentration. In severely sodium-depleted marmosets, CGP 29 287 (1.0 mg/kg i.v.) induced a marked fall in systolic blood pressure and complete inhibition of plasma renin activity within 30 minutes of injection. Plasma immunoreactive renin levels increased to 257% of pretreatment values. The converting-enzyme inhibitor enalaprilat (2 mg/kg i.v.) induced a fall in systolic blood pressure of similar magnitude, which was accompanied by an increase in plasma renin activity. Levels of plasma immunoreactive renin increased to 210% of pretreatment values. Hydralazine (0.2 mg/kg i.v.) did not increase plasma renin activity or plasma immunoreactive renin levels despite a comparable hypotensive effect.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension
PMID:Increased plasma renin during renin inhibition. Studies with a novel immunoassay. 298 26

Spontaneously hypertensive rats (SHR) demonstrate an elevated minimal coronary vascular resistance by the seventh month of age. In an attempt to determine the role of long-standing hypertension in the etiological process of the elevated minimal coronary vascular resistance, we treated SHR and normotensive Wistar-Kyoto rats (WKY) with the vasodilator hydralazine from the time of weaning (1 month) until they were 7 to 8 months of age. The animals were instrumented 24 hours after their last drug dose and then studied on the following day. Using microspheres we measured myocardial perfusion in conscious rats at rest and during maximal coronary dilation induced with dipyridamole infusion. Hydralazine maintained arterial blood pressures in the normotensive range throughout the experimental period, but had little effect on left ventricular weight/body weight ratios (control SHR = 2.95 +/- 0.07, treated SHR = 2.73 +/- 0.08, control WKY = 2.39 +/- 0.09, mean +/- SEM). In treated SHR, left ventricular minimal coronary vascular resistance (per 100 g of tissue) was markedly lower (0.10 +/- 0.01) than in the controls (0.16 +/- 0.01) and not significantly different from that of WKY (0.11 +/- 0.01). Similar differences were noted in the nonhypertrophic right ventricle (treated SHR = 0.08 +/- 0.01, control SHR = 0.16 +/- 0.01, control WKY = 0.10 +/- 0.01). Total minimal coronary vascular resistance was also lower in both ventricles of the treated SHR compared with their nontreated controls. In WKY, hydralazine treatment significantly reduced blood pressure and total minimal coronary vascular resistance (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension
PMID:Prevention of coronary vasodilator reserve decrement in spontaneously hypertensive rats. 315 64

Nine children, hospitalized for severe respiratory failure following scorpion envenomation, were a part of a group of 61 youngsters and infants admitted to the Pediatric Intensive Care Unit of the Soroka Medical Center, Beer-Sheva during the years 1983-87 because of scorpion venom intoxication. Four out of the nine had cardiogenic shock, three had severe systemic hypertension and one had severe airway obstruction. All nine patients had central nervous system manifestations, including lethargy, confusion and agitation (three cases), and markedly reduced level of consciousness (six cases). Hemodynamic studies performed in two patients showed 'high pressure' (cardiogenic) pulmonary edema. Seven patients recovered completely, one died and another one was left severely handicapped. Hydralazine i.v. showed a remarkable effect on the systemic blood pressure and central nervous system disturbances in addition to mechanical ventilation. Based on our own experience and previous clinical and experimental studies, the possible pathogenetic mechanisms underlying the respiratory and central nervous system dysfunction following scorpion sting are discussed.
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PMID:Respiratory failure in children following envenomation by the scorpion Leiurus quinquestriatus: hemodynamic and neurological aspects. 320 82

Sixty peripartum patients with diastolic blood pressures (BP) 110 mmHg or higher were randomized in a 2:1 ratio to receive repeated intravenous injections of either labetalol (20-80 mg) or hydralazine (5 mg) until the diastolic BP was below 100 mmHg. There were four treatment failures in the labetalol group (N = 40) and none in the hydralazine group (N = 20). Hydralazine lowered mean arterial pressure (MAP) more than did labetalol (33.3 +/- 13.2 versus 25.5 +/- 11.2 mmHg; mean +/- SD), but labetalol had a more rapid effect. There was considerable interpatient variability in the dose of labetalol required to control BP, which could not be predicted by any clinical characteristic before therapy. The duration of action also varied in the labetalol group, with the shortest duration occurring in those patients who required the highest dosage for BP control. No significant fetal or neonatal problems ascribable to drug treatment were noted in the 13 instances in which labetalol was given before delivery. However, fetal distress occurred in two of the six cases involving antenatal hydralazine. We conclude that labetalol appears to be a safe and effective alternative to hydralazine for treating hypertension in the peripartum period, but serious rare side effects have not yet been quantified.
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PMID:A comparative trial of labetalol and hydralazine in the acute management of severe hypertension complicating pregnancy. 330 94


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