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PubMed1978

A comparison between spironolactone and hydrochlorothiazide with and without alpha-methyldopa in the treatment of hypertension.

In a single blind crossover trial, spironolactone (50 mg twice a day), and hydrochlorothiazide (50 mg twice a day) were equally effective hypotensive agents in 16 patients with untreated essential hypertension. The addition of alpha-methyldopa (250 mg three times a day) to each agent produced a further significant and equal fall in blood pressure. Spironolactone therapy was assoicated with fewer clinical and biochemical side effects. The hypotensive effect of the diuretics was independent of the renin status of the patients.

Adult↗
PubMed2003

Pharmacokinetic profile of methyldopa in the brain of sinaortic-denervated rats.

Pharmacokinetics of methyldopa (MD) and the effect on the dopaminergic metabolism was studied in anesthetized sham-operated (SO) and sinoaortic-denervated (SAD) rats by using the microdialysis technique. A concentric microdialysis probe was placed in the striatum or in the posterior hypothalamus. Levels of MD, homovanillic acid (HVA), and 3,4-dihydroxyphenylacetic acid (DOPAC) were measured by high pressure liquid chromatography coupled to electrochemical detection (HPLC-EC). Following the i.p. administration of MD (50 mg x kg(-1), i.p.), striatal dialysates showed that this drug rapidly reaches the brain. However, in SAD rats the MD levels of dialysates were lower and decreased more rapidly compared to SO rats. On the other hand, dialysates of posterior hypothalamus showed that in SAD animals the accumulation of MD was significantly greater than in SO rats.MD does not significantly reduce the striatal production of dopaminergic metabolite DOPAC in both groups of rats. The drug also induces a decrease of DOPAC levels in hypothalamic dialysates of SO and SAD animals. On the other hand, a no significative decay of HVA levels was seen in the striatal dialysate of both groups of experimental animals. In conclusion, this study by using a microdialysis technique shows that MD has different kinetic profiles in dialysates from posterior hypothalamus and striatum of SO and SAD rats at a dose that alters dopaminergic metabolism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Synthesis of substituted DL-3(5-benzazolyl)alanines as dopa and alpha-methyldopa analogs and their effects on dopamine beta-hydroxylase, tyrosinase and diphenoloxidase.

The influence of bioisosteric replacement of catechol moiety of L-Dopa and alpha-Methyldopa with benzimidazole and benzotriazole ring has been examined on dopamine beta-hydroxylase and tyrosinase, in order to evidentiate an inhibitory activity on the synthesis of catecholamines and a possible antihypertensive action. The preliminary results obtained so far showed that inhibition of dopamine hydroxylase occurs at 5 x 10(-4) M concentration for the most active compounds bearing a trifluoromethyl group in the azole ring (2a,c). An analogous result was observed in the case of tyrosinase inhibition with compound 2c, while other compounds (2a,e) were equiactive (92% inhibition) at higher concentration (1 x 10(-3) M). Compound 2c was also the most active in inhibition of diphenoloxidase (83% at 6 x 10(-5) M concentration).

Adrenal Glands↗
PubMed2004

[Methyldopa in therapy of hypertension in pregnant women].

Both chronic hypertensive disorders in pregnancy and pregnancy-induced hypertension are the main causes of morbidity and mortality of mothers and fetuses. The great significance in the prevention of serious complications of them has properly pharmacology treatment. One of the most early and the most often used drug is Methyldopa--a drug from the group acting via central nervous system, causing the depression in the cardio-vascular system.

Antihypertensive Agents↗
PubMed1991

Neonatal effects of methyldopa therapy in pregnancy hypertension.

This study has been performed to assess the effect of methyldopa (MD) therapy in pregnancy hypertension on the neonatal adaptation. Infants born to mothers on MD for several weeks prior to delivery and presenting with excessive tremor and irritability were evaluated according to the dose of maternal MD. Pregnancy hypertension and high dose MD was associated with impaired placental perfusion, compromised function of fetoplacental unit and more frequent surgical delivery. Infants of mothers on high (1.25-2.0 g/day) or low (less than 1 g/day) MD had gestational age, head circumference, acid-base balance, Apgar score and blood pressure similar to those born to healthy control mothers. The birth weight of infants of the high MD group, however, were significantly lower than in the low-dose or control groups. MD therapy resulted in a dose-dependent increase in plasma levels of prolactin, thyrotropin and triiodthyronine indicating decreased dopaminergic inhibition of pituitary hormone release. Plasma thyroxine concentration, however, decreased significantly. Cerebrospinal fluid noradrenaline was found to be markedly depressed after maternal MD showing disturbed central nervous system monoamine metabolism. It is suggested that MD administration to mothers presenting with pregnancy hypertension interferes with cerebral monoamine metabolism of the neonate and induces alterations in some endocrine functions under dopaminergic control. The possible role of chronic fetal distress frequently associated with pregnancy hypertension should also be considered.

Adaptation, Physiological↗
PubMed1990

Combination of a thiazide, a vasodilator and reserpine compared with methyldopa plus hydrochlorothiazide in the treatment of hypertension in Zimbabwe.

Brinerdin (Sandoz), a combination of a diuretic (clopamide 5 mg), a vasodilator (dihydro-ergocristine 0.5 mg) and reserpine (0.1 mg) (CDR) was compared with methyldopa (MD) plus hydrochlorothiazide (HCT) for antihypertensive effect, adverse reactions, compliance and patient preference in an open cross-over trial. Eighteen patients completed both arms of the trial and 5 patients who completed the CDR arm were withdrawn while on the MD arm because of adverse effects in 4 and poor control in 1. On HCT 50 mg daily the mean baseline systolic blood pressure was 163.9 +/- 16.3 mmHg and the diastolic blood pressure was 105.9 +/- 6.7 mmHg. On CDR these were reduced to systolic blood pressure 140.3 +/- 15.1 mmHg and diastolic blood pressure 87.8 +/- 9.3 mmHg. On MD + HCT the systolic blood pressure was reduced to 138.5 +/- 16.9 mmHg and the diastolic blood pressure to 88.9 +/- 10.3 mmHg. The differences between the two treatment periods in systolic blood pressure (1.8 mmHg; 95% confidence interval (CI) - 4.1 + 7.7 mmHg) and diastolic blood pressure (1.1 mmHg; 95% CI - 4.6 + 2.4 mmHg) were not significant with P values of 0.6 and 0.7 respectively. Compliance was 98.2% for CDR and 94.7% for MD + HCT (P = 0.02). Unusual sleepiness occurred more frequently in the MD arm (P less than 0.01). Thirteen patients chose to continue on CDR, 2 on MD + HCT and 3 had no preference (P = 0.005). CDR is similar in antihypertensive effect to MD + HCT but is better tolerated with fewer withdrawals, fewer adverse effects, better compliance and has more patients electing to continue taking it.

Adult↗
PubMedDate not supplied

Ramipril and methyldopa compared in patients with mild to moderate hypertension.

Twenty-seven patients with mild to moderate essential hypertension were randomly assigned to receive 5 mg of ramipril once daily or 250 mg of methyldopa twice daily for eight weeks. Similar reductions in diastolic blood pressure and heart rate were noted in the two treatment groups during treatment. Perhaps because of the limited number of patients, no between-group differences in the results of a measure of quality of life were found, but on overall assessments of treatment outcome by patients and the investigator, slightly better outcome was apparent in the ramipril-treated patients. No side effects or clinically significant changes in laboratory test results were reported. It is concluded that ramipril is a safe and effective agent in mild to moderate hypertension when administered as a single daily dose.

Adult↗
PubMed1990

Indoramin in the treatment of pregnancy hypertension. A placebo-controlled trial comparing the efficacy of indoramin with alpha-methyldopa.

A placebo-controlled trial was used to assess the antihypertensive efficacy of indoramin in the management of pregnancy hypertension. Sixty patients were recruited into the study and only 17 attained satisfactory blood pressure control. In the doses of drugs administered indoramin was not shown to be more effective than alpha-methyldopa.

Drug Therapy, Combination↗
PubMed1990

Coulometric determination of levodopa, methyldopa and carbidopa.

A simple and rapid method for the assay of small quantities of levodopa, methyldopa and carbidopa is presented. The method is based on coulometric titration of the investigated substances with electrogenerated chlorine in the presence of methyl orange as indicator. Results are accurate and reproducible. The method does not require any expensive instrumentation and can be applied in any laboratory for routine analysis of these substances.

Azo Compounds↗
PubMedDate not supplied

Differential blood pressure responses to intracisternal clonidine, alpha-methyldopa, and 6-hydroxydopamine in conscious normotensive and spontaneously hypertensive rats.

The cardiovascular effects of three drugs that activate central alpha-adrenoceptor mechanisms were investigated in conscious normotensive Wistar and Wistar-Kyoto rats, and in spontaneously hypertensive rats (SHR). From dose-response curves, near-maximal intracisternal (i.c.) depressor doses of clonidine, alpha-methyldopa (alpha-MD), and 6-hydroxydopamine (6-OHDA; a neurotoxic agent that acutely releases central noradrenaline) were determined. In all three strains of rats, alpha-MD (1 mg i.c.) produced a 23-25% reduction in blood pressure. Clonidine (2.5 micrograms i.c.) and 6-OHDA (400 micrograms i.c.) produced similar falls in blood pressure in SHR to that observed with alpha-MD, but they were much less effective in normotensive rats (7 and 13%, respectively, in Wistar; 22 and 21% in SHR). Higher doses of clonidine increased blood pressure in Wistar rats, but further reduced it in SHR. The late pressor response observed 2-3 h after 6-OHDA administration in Wistar rats was not observed in SHR. These results support the view that clonidine and 6-OHDA, but not alpha-MD, have central pressor actions in the rat that oppose their antihypertensive action. The absence of this pressor effect in SHR indicates that there are significant differences in central noradrenergic pathways and alpha-adrenoceptor distribution among the three strains of rats.

Animals↗
PubMed1987

Evaluation of a new antihypertensive agent ketanserin versus methyldopa in the treatment of essential hypertension in older patients: an international multicenter trial.

The serotonergic antagonist ketanserin (K) was compared to methyldopa (M) in a four-center international study in 119 hypertensive patients over 50 years of age. After a 4-week placebo run-in period, patients randomly received K (20-40 mg b.i.d.) or M (250-500 mg b.i.d.) for 3 months. The drugs were given in monotherapy for at least 1 month, then a diuretic could be added if blood pressure remained abnormally high. For the patients on monotherapy, active drug was replaced by placebo at the end of the 3-month period until the patients were hypertensive again. K and M had a similar effect on systolic blood pressure, but diastolic blood pressure was reduced significantly more by K than by M. Significantly more patients had their blood pressure normalized in the K group (75%) than in the M group (49%). The twice daily dosage schedule caused trough blood pressure control with both drugs. No rebound hypertension occurred at discontinuation of treatment. Monotherapy with K caused a decrease in heart rate (-5 beats/min) while M produced no change. Body weight decreased with K (-0.5 kg) and increased with M (+ 0.4 kg). No important hematological or biochemical changes were seen with either drug. Slightly fewer patients reported adverse reactions during K monotherapy (40%) than with M (45%). In the latter group mainly central side effects were observed. The data confirm K to be an effective first-line antihypertensive agent with a favorable side-effect profile.

Blood Pressure↗
PubMed1989

Treatment of resistant hypertension: 3 years of follow-up with the combination of verapamil and methyldopa.

A combination of verapamil (V), methyldopa (M), and hydrochlorothiazide (H) was tried in hypertensive patients resistant to the usual stepped-care therapy. After at least 60 days with a third-step regimen, placebo was added during the last 2 weeks. Twenty patients whose diastolic blood pressure (DBP) remained greater than 100 mm Hg were assigned to the study. During the initial titration period patients received increasing doses of V (240-480 mg) and M (500-1,500 mg). H was kept at 50 mg/day. Other previously administered drugs were gradually withdrawn. Goal pressure was DBP less than or equal to 95 mm Hg. Follow-up lasted 3 years. Sixteen patients participated in the investigation until the end and all but one reached the goal DBP. Mean systolic BP dropped from 187 +/- 17 to 150 +/- 15 mm Hg (p less than 0.05) and DBP from 118 +/- 12 to 90 +/- 9 mm Hg (p less than 0.01). Adverse effects were rare and mild. Other control measurements did not show any change except improvement of the electrocardiogram of 11 patients, and of the optic fundus of 10 patients. The number of drug unities to be taken dropped from 10 +/- 4 to 7 +/- 2 (p less than 0.05). The abovementioned combination seems to be useful in the control of resistant hypertension. Efficacy was sustained and tolerability was excellent. A potential to reverse target organ damage, namely of the heart and optic fundus, is suggested.

Adult↗
PubMed1989

[Efficacy and acceptability of rilmenidine in mild to moderate arterial hypertension. A multicenter, randomized, double-blind trial, in comparison with methyldopa in 157 patients].

UNLABELLED: A dissociation between the hypotensive activity and the central side effects has been demonstrated with rilmenidine (RIL) in previous studies. The object of this trial was to compare RIL with methyldopa (MD) during a 12 weeks' treatment (Day 0 to Day 84) and after stopping therapy (Day 84-Day 91). In particular, the trial was designed to evaluate the acceptability of the two agents. After 4 weeks of placebo, 76 men and 81 women (average age 55 years) were allocated according to a randomised double-blind protocol to RIL (N = 78) or MD (N = 79). The two groups were comparable with systolic/diastolic BP of 165/102 mmHg and 165/101 mmHg respectively. Monotherapy was administered to all the patients from Day 0 to Day 56 in order to compare RIL (1 mg every morning or 1 mg twice daily if necessary) and MD (250 mg morning and evening or 500 mg twice daily if necessary). Hydrochlorothiazide (25 mg daily) was associated from Day 56 to Day 84 if the supine diastolic BP was greater than or equal to 90 mmHg. A placebo was substituted from Day 84 to Day 91 to study the effect of withdrawing therapy. RESULTS: at Day 56 under monotherapy, the average supine systolic/diastolic BP had decreased significantly with RIL and MD to 140/110 mmHg and 140/100 mmHg respectively. An equivalent number of patients had normalised their blood pressures in both groups (systolic/diastolic BP less than or equal to 160/90 mmHg): 50% with RIL and 42% with MD (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Spectrophotometric determination of microquantities of Carbidopa, Levodopa and alpha-methyldopa using molybdatophosphoric acid.

A convenient spectrophotometric procedure for the determination of microquantities of Carbidopa (I), Levodopa (II) and alpha-methyldopa (III) was developed. The method was based on the interaction of acidified molybdatophosphoric acid (MPA) solution with (I), (II) and (III). The resulted deep blue solution was measured spectrophotometrically at lambda = 600-900 nm. The molar absorptivities (epsilon) and the Sandell's sensitivity for (I), (II) and (III) were: 2.4 x 10(4) (I), 3.0 x 10(4) (II), 3.1 x 10(4) (III) and 10.2 ng.cm-2 (I), 6.6 ng.cm-2 (II) and 7.7 ng.cm-2 (III), respectively. The calibration curves were conformed to Lambert-Beer's law between 0.5 and 10.0 micrograms.ml-1.

Carbidopa↗
PubMed1978

Sodium and fluid balance during hypotensive response to alpha-methyldopa.

1. Detailed observations on sodium and fluid balance during treatment with alpha-methyldopa were made in five hypertensive patients. The initial fall in blood pressure concurred with a decline in fluid and sodium excretion. Sodium balance increased 100-300 mEq. In one patient with serve hypertension the sodium balance was incompletely restored, the relationship with blood pressure indicating a negative feedback loop. In the other patients sodium balance reverted to baseline, while the hypotensive response was maintained. This is probably due to a decrease in renal arteriolar tone. 2. Parallel systemic and renal vasodilatation may account for the discrepancy between a significant increase in blood volume and insignificant long-term changes in the fluid and sodium status.

Adult↗
PubMed1978

Clinical experiences with methyldopa.

1. The hypotensive effect of methyldopa alone or associated with other hypotensive drugs was evaluated in 155 patients. After 10 days of treatment, the blood pressure was back to normal in 80% and in 50% of the patients with mild and moderate hypertension, and it was significantly decreased in those with severe hypertension. 2. Contrary to other hypotensive drugs, it did not produce a significant increase in BUN and serum creatinine. Occasional or recurrent episodes of orthostatic hypotension were observed in about 18% of the cases, but in none did it produce important symptoms of cerebral or myocardial ischaemia.

Blood Pressure↗
PubMed1986

Black tongue secondary to methyldopa therapy.

A case of black tongue associated with methyldopa administration is reported. The symptoms disappeared when the medication was discontinued. The possible mechanism is discussed.

Humans↗