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

Twenty-five patients whose pregnancies were complicated by chronic hypertension were entered in a double-blind study and randomly allocated to treatment with methyldopa (Aldomet) or placebo. Thirteen patients were in the treatment group and 12 in the placebo group. The two groups showed no significant difference in demographic and pretreatment laboratory profiles. Methyldopa-treated patients registering in the first trimester had a significant reduction in the mean arterial pressure (MAP) during the second and third trimesters (P less than 0.025). No significant differences in birth weight (BW), ponderal index (PI) were found when results were corrected for gestational age (GA), race, and sex. The mean GA was significantly prolonged in the methyldopa-treated group by 10.3 days (P less than 0.05). The frequency of superimposed pre-eclampsia was similar in both groups (33.3% vs. 38.4%). However, 75% of the superimposed pre-eclampsia occurred antepartum in the placebo group, while 80% of the methyldopa-treated group developed superimposed pre-eclampsia intrapartum. The results of this small study suggest that the treatment of hypertension in pregnancy may reduce MAP and possibly delay the occurrence of superimposed pre-eclampsia and thus afford a prolongation of the pregnancy.
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PMID:Treatment of hypertension in pregnancy with methyldopa: a randomized double blind study. 288 43

Methyldopa therapy for hypertension after renal transplantation could affect graft outcome adversely, since methyldopa inhibits suppressor cells. To study effects of methyldopa on transplant outcome, we analyzed prospective data on 1,648 hypertensive, first-allograft recipients; 545 patients used methyldopa and 1,103 patients did not. One-year graft functional survival was 66% and 67% for all patients using and not using methyldopa respectively. No increased acute rejection occurred related to methyldopa. During the one to six years of follow-up, no adverse effects on graft survival could be attributed solely to methyldopa except that graft survival among white recipients using methyldopa was diminished late after transplantation (P less than .05). Patient survival was not affected by methyldopa. Azathioprine and prednisone therapy may avert the suppressor cell inhibition by methyldopa. Its effect on kidney transplant outcome is not significant except in whites late in the course of graft function; methyldopa use when clinically indicated appears safe.
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PMID:Methyldopa therapy and outcome in cadaveric renal transplantation. 389 1

A self-administered symptom questionnaire was completed by 477 patients in a hypertension clinic. The complaints of the patients were analysed according to the type of therapy being given and the dose of drug taken. Methyldopa therapy was associated with sleepiness, weakness of the limbs, sleeping longer at night, and rising more frequently at night to pass urine. Diarrhoea, impotence, failure of ejaculation, blurred vision, depression, and the symptoms of postural hypotension were not related to methyldopa therapy. Bethanidine administration was related to postural hypotension, impotence, and failure of ejaculation but not to weakness of the limbs, blurred vision, depression, or diarrhoea. Patients receiving guanethidine complained of postural hypotension, failure of ejaculation, and had their bowels open more frequently. Similarly, patients receiving propranolol had an increased frequency of defaecation but also tended to complain of weakness of the limbs.Considering each drug individually, 5% of patients failed to take the prescribed dose of diuretic whereas
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PMID:Side effects of hypotensive agents evaluated by a self-administered questionnaire. 472 58

During the study of an inbred strain of Wistar rats which spontaneously develop hypertension when they reach a weight of approximately 150 g, it was found that these animals also develop an erythrocytosis. A significant increase in red cell count was observed in spontaneously hypertensive (SH) rats (8-11 x 10(6) RBC/mm(3)) when compared with normotensive rats (6-7 x 10(6) RBC/mm(3)) of the same strain. This increase in red cell count paralleled the increase in body weight and the rise in blood pressure. Since the plasma volume, as measured with labeled albumin was normal, there was an absolute increase in red cells. The hematocrit and hemoglobin content of the blood measured in SH rats were only slightly greater than those found in normotensive rats. However, the mean cell volume (MCV) of the red cells in the SH rats was 45-47 mu(3) as compared with 51-53 mu(3) in normotensive rats.A fourfold increase in 24 hr (59)Fe incorporation into the red cells was found in the SH rats when compared with normotensive controls. The bone marrow of the SH rats showed erythroid hyperplasia. When the SH rats were treated with alpha-methyldopa (Aldomet 200 mg/kg daily, i.p.) the red cell count fell in parallel with the drop in blood pressure. No change in red cell count or blood pressure was observed in normotensive rats treated in the same manner. The erythropoietin titer was high in SH rats, and was undetectable in normotensive rats. These observations suggest a direct relationship between the hypertension and the erythrocytosis mediated by erythropoietin; both are genetically controlled.
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PMID:Erythrocytosis in spontaneously hypertensive rats. 501 Nov 7

A trial of methyldopa in hypertension was conducted in 60 patients for a mean time of 9.4 months. Initially, four different dosages of methyldopa were studied and blood pressure was significantly lowered in the supine and standing positions. Standing blood pressure was significantly reduced more than supine. An average of 5.2 visits passed before maintenance blood pressure was obtained. There was no significent evidence of deterioration during the duration of this study. Side effects were mild. Only two patients voluntarily requested discontinuance of this study. Tolerance to the drug occurred and approximately 50 per cent of the patients no longer had a significant blood pressure reduction to methyldopa alone by the end of the study. Methyldopa appears to be a significant addition to the drug therapy of hypertension.
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PMID:The long-term effectiveness of methyldopa in hypertension. 590 53

Methyldopa, clonidine, and a more recently developed drug, guanabenz, have similar antihypertensive mechanisms, predominantly suppression of central sympathetic outflow by alpha 2-receptor agonism and consequent reduction in peripheral sympathetic activity. Recent studies clearly demonstrate an important role of the sympathetic nervous system in the control of sodium excretion. Therefore, the interrelationships between the use of central alpha-adrenergic agonists as antihypertensive agents and their influence on renal handling of sodium are important. Certain problems accompany the use of the older centrally acting drugs as monotherapy. As a response to the hypotensive effects of these drugs, certain renal adaptations take place which presumably are homeostatic attempts to restore blood pressure and plasma volume to baseline, but which lead to a positive sodium balance, antihypertensive tolerance and occasionally the development of overt edema. The high incidence of tolerance has led most physicians to use diuretics on a routine basis, superimposing the side effects of diuretics and compromising compliance. The potential natriuretic properties of guanabenz appear to counter-balance the sodium retaining side effects commonly seen with other centrally acting and vasodilating antihypertensive drugs. This property, therefore, makes this agent a scientifically interesting and potentially useful therapeutic drug for the therapy of high blood pressure.
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PMID:Natriuretic and water diuretic effects of central alpha 2-adrenoceptor agonists. 608 25

Overall, the worldwide experience on enalapril to date is very encouraging. The drug produces good to excellent responses in 54 to 66 percent of patients with essential hypertension and is at least as effective as either diuretics or beta blockers. The effects of enalapril compared with those of diuretics confirm that patients more dependent upon the renin-angiotensin system respond better. When hydrochlorothiazide is administered concomitantly with enalapril, almost all patients respond, with good long-term maintenance. In patients with severe hypertension, Blocadren or Aldomet may be added in addition to hydrochlorothiazide and will produce additional benefit. Enalapril attenuates the adverse metabolic effects of hydrochlorothiazide, particularly hypokalemia. Overall, although the efficacy of enalapril and that of captopril are similar, enalapril is better tolerated and does not appear to be associated with any significant occurrence of captopril-type side effects, particularly the skin rash and loss of taste. As expected, enalapril and other converting inhibitors may be associated with azotemia in patients with bilateral renovascular hypertension.
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PMID:Enalapril worldwide experience. 608 56

Clonidine (Catapres, Catapresan), guanfacine (Estulic), and methyldopa (Aldomet) are the prototypes of centrally acting antihypertensive drugs. Clonidine and guanfacine are lipophilic drugs that readily penetrate into the brain, where they stimulate alpha-adrenergic receptors in the pontomedullary region. The stimulation of these central alpha-adrenergic receptors has been shown to activate an inhibiting neuron, which causes a reduction of peripheral sympathetic tone and a subsequent fall in arterial blood pressure and heart rate. Both a centrally initiated reduction of vagus reflex activity and the activation of presynaptic alpha 2-adrenergic blocking agents in the heart may contribute to the bradycardia. Studies indicate that methyldopa also penetrates into the brain, where it is converted into alpha-methylnorepinephrine. This amine may stimulate the same central alpha-adrenergic receptors as those activated by clonidine, which will result in a hypotensive effect. Possibly, alpha-methyldopamine might also play a role. Accordingly, the modes of action of clonidine and alpha-methyldopa probably are very similar at a basic level. The central adrenergic receptors probably are located postsynaptically. Their receptor demand corresponds more closely to that of the alpha 2-subtype. Central alpha 1-adrenergic receptors might possibly play a part in the modulation of vagally induced baroreflex bradycardia. A discussion on the pharmacological basis of the side effects of the centrally acting antihypertensives has been limited to those adverse reactions that are somehow related to alpha-adrenergic receptors. Sedation, a common side effect, appears to be mediated by central alpha 2-adrenergic receptors, at least in animal models.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension
PMID:The hypotensive activity and side effects of methyldopa, clonidine, and guanfacine. 609 46

Once the diagnosis of chronic hypertension in pregnancy has been made, many centers in the United States treat moderate to severe cases of chronic hypertension pharmacologically, hoping to delay or obviate the onset of superimposed preeclampsia and to improve perinatal outcome. Methyldopa, which is most often used, is the only antihypertensive drug for which there is no evidence of adverse effects in long-term follow-up studies of fetuses exposed to it. Newer beta-blocker drugs such as atenolol and labetalol are receiving much attention abroad. These newer drugs have fewer maternal side effects and, as yet, no adverse effects on fetuses have been seen. Clinical trials of labetalol will soon start in the United States.
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PMID:Management of the pregnant patient with chronic hypertension. 613 51

There are few studies of hypertension in Sudan. In this report, 124 patients attending a newly established hypertension clinic are studied, most of whom were taking irregular treatment initially. Seventy-three (59%) had a strong family history of hypertension. There was a very low incidence of cigarette smoking (13.7%), and alcohol consumption (4.8%). As with blacks in the U.K. and the U.S.A., the commonest complications were cerebrovascular accidents and congestive cardiac failure. Most of the patients had moderately elevated blood pressures on the first visit, which fell significantly after 3 and 6 months of clinic attendance. Methyldopa and thiazides were the commonest drugs used, but a small pilot survey demonstrated that beta-blockers were effective. The high cost and poor availability of drugs contribute to poor compliance in these patients.
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PMID:A blood pressure clinic in a developing country. 613 97


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