Each film-coated tablet contains: Methyldopa equivalent to Anhydrous Methyldopa 250 mg.
Pharmacotherapeutic group: antiadrenergic agents.
Pharmacology: Pharmacodynamics: Mechanism of action: It appears that several mechanisms of action account for the clinically useful effects of methyldopa and the current generally accepted view is that its principal action is on the central nervous system. The antihypertensive effect of Methyldopa is probably due to its metabolism to alpha-methylnoradrenaline, which lowers arterial pressure by stimulation of central inhibitory alpha-adrenergic receptors, false neurotransmission, and/or reduction of plasma renin activity. Methyldopa has been shown to cause a net reduction in the tissue concentration of serotonin, dopamine, epinephrine (adrenaline) and norepinephrine (noradrenaline).
Pharmacokinetics: Following oral administration, Methyldopa is variably and incompletely absorbed, apparently by an amino-acid active transport system. The mean bioavailability has been reported to be about 50%. It is extensively metabolized and is excreted in urine mainly as unchanged drug and the O-sulfate conjugate. It crosses the blood-brain barrier and is decarboxylated in the CNS to active alpha-methylnoradrenaline.
The elimination is biphasic with a half-life of about 1.7 hours in the initial phase; the second phase is more prolonged. Clearance is decreased and half-life prolonged in renal impairment. Plasma protein binding is reported to be minimal. Methyldopa crosses the placenta; small amounts are distributed into breast milk.
For the treatment of mild to moderate hypertension.
In hypertension, the usual dose by mouth is 250 mg, two or three times daily for 2 days; this is then adjusted by small increments or decrements not more frequently than every 2 days according to the response of the patient. The usual maintenance dosage is 0.5 to 2 g of Methyldopa daily. In the elderly an initial dose of 125 mg twice daily has been recommended; this dose may be increased gradually if necessary, but should not exceed 2 g daily.
Or as directed by the physician.
Symptoms: Acute overdosage may produce acute hypotension with other responses attributable to brain and gastrointestinal malfunction (excessive sedation, weakness, bradycardia, dizziness, light-headedness, constipation, distension, flatus, diarrhea, nausea, and vomiting).
Management: If ingestion is recent, emesis may be induced or gastric lavage performed. There is no specific antidote. Methyldopa is dialysable. Treatment is symptomatic. Infusions may be helpful to promote urinary excretion. Special attention should be directed towards cardiac rate and output, blood volume, electrolyte balance, paralytic ileus, urinary function and cerebral activity.
Administration of sympathomimetic agents may be indicated. When chronic overdosage is suspected, Methyldopa should be discontinued.
Methyldopa tablets are contraindicated in patients with: Phaeochromocytoma, Depression, Hepatic impairment, Jaundice, Hypersensitivity.
Should be used in caution in patients with: Pregnancy, Patients may develop a positive direct Coomb's test, Renal impairment, Acquired hemolytic anemia.
Pregnancy: Methyldopa has been used under close medical supervision for the treatment of hypertension during pregnancy. There was no clinical evidence that Methyldopa caused foetal abnormalities or affected the neonate.
Published reports of the use of Methyldopa during all trimesters indicate that if this drug is used during pregnancy, the possibility of fetal harm appears remote.
Methyldopa crosses the placental barrier and appears in cord blood.
Although no obvious teratogenic effects have been reported, the possibility of fetal injury cannot be excluded and the use of the drug in women who are, or may become pregnant requires that anticipated benefits be weighed against possible risks.
Breastfeeding: Methyldopa appears in breast milk. The use of the drug in breastfeeding mothers requires that anticipated benefits be weighed against possible risks.
Sedation, lethargy, reduced mental capacity, dry mouth, fluid retention, weight gain, impotence, nasal congestion, postural hypotension.
The hypotensive effects of Methyldopa are potentiated by diuretics, other antihypertensives, and drugs with hypotensive effects. However, there have been reports of paradoxical antagonism of the hypotensive effects by tricyclic antidepressants, antipsychotics, and beta blockers.
Sympathomimetics may also antagonize the hypotensive effects.
There may be an interaction between Methyldopa and MAOIs and care is required if they are given concomitantly. Caution is also needed with entacapone since it might inhibit the metabolism of Methyldopa.
Patients receiving Methyldopa may require lower doses of general anaesthetics.
Store at temperatures not exceeding 30°C.
Protect from light.
C02AB01 - methyldopa (levorotatory) ; Belongs to the class of methyldopa, centrally-acting antiadrenergic agents. Used in the treatment of hypertension.
Sign Out
Continue with Google
Sign up with email
Already a member?
Sign in
