Methyldopa(meth ill doe’ pa)
Methyldopa
Apo-Methyldopa (CAN), Nu-Medopa (CAN)
Methyldopate Hydrochloride
PREGNANCY CATEGORY B (ORAL)
PREGNANCY CATEGORY C (IV)
Drug Classes
Antihypertensive
Sympatholytic (centrally acting)
Therapeutic Actions
Mechanism of action not conclusively demonstrated; probably due to drug’s metabolism, which lowers arterial BP by stimulating CNS alpha2-adrenergic receptors, which in turn decreases sympathetic outflow from the CNS.
Indications
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Hypertension
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IV methyldopate: Acute hypertensive crisis; not drug of choice because of slow onset of action
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Unlabeled use: Hypertension of pregnancy
Contraindications and Cautions
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Contraindicated with hypersensitivity to methyldopa, active hepatic disease, previous methyldopa therapy associated with liver disorders, concurrent use of MAOIs.
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Use cautiously with previous liver disease, renal failure, dialysis, bilateral cerebrovascular disease, pregnancy, lactation, and in elderly patients.
Available Forms
Tablets—250, 500 mg; injection—50 mg/mL
Dosages
Adults
Oral therapy (methyldopa)
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Initial therapy: 250 mg PO bid–tid in the first 48 hr. Adjust dosage at minimum intervals of at least 2 days until response is adequate. Increase dosage in the evening to minimize sedation. For maintenance, 500 mg–2 g/day in two to four doses. Usually given in two to four doses; some patients may be controlled with a single dose at bedtime.
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Concomitant therapy: With antihypertensives other than thiazides, limit initial dosage to 500 mg/day PO in divided doses. When added to a thiazide, dosage of thiazide need not be changed.
IV therapy (methyldopate)
250–500 mg IV every 6 hr as required (maximum 1 g every 6 hr). Switch to oral therapy as soon as control is attained; use the dosage schedule used for parenteral therapy.
Pediatric patients
Oral therapy (methyldopa)
Individualize dosage; initial dosage is based on 10 mg/kg/day PO in two to four doses. Maximum dosage is 65 mg/kg/day or 3 g/day, whichever is less.
IV therapy (methyldopate)
20–40 mg/kg/day IV in divided doses every 6 hr. Maximum dosage is 65 mg/kg or 3 g/day, whichever is less.
Geriatric patients and patients with impaired renal function
Reduce dosage. Drug is largely excreted by the kidneys.
Pharmacokinetics
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