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
Hypertension
IV methyldopate: Acute hypertensive crisis; not drug of choice because of slow onset of action
Unlabeled use: Hypertension of pregnancy
Contraindications and Cautions
Contraindicated with hypersensitivity to methyldopa, active hepatic disease, previous methyldopa therapy associated with liver disorders, concurrent use of MAOIs.
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)
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.
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.
