Adults: 250 mg orally 2–3 times daily; may increase gradually to 2 g/day in divided doses
Pregnancy: Same dosing; commonly used in gestational hypertension or preeclampsia management
Children: 10–30 mg/kg/day in 2–3 divided doses (specialist guidance required)
Note: Dose adjustments may be required in renal impairment. Monitor blood pressure and liver function.
Route of Administration
Oral (tablet, oral solution), IV (rare, inpatient use)
Mechanism of Action
Methyldopa is converted to alpha-methyl norepinephrine in the CNS, which stimulates central alpha-2 adrenergic receptors. This reduces sympathetic outflow, leading to decreased peripheral vascular resistance and lower blood pressure.
Common Adverse Effects
Drowsiness, sedation
Headache
Dry mouth
Weakness
Orthostatic hypotension
Serious Adverse Effects
Hepatotoxicity (rare)
Hemolytic anemia or positive Coombs test
Severe hypotension
Bradycardia
Contraindications
Hypersensitivity to methyldopa
Active liver disease
Concurrent use with MAO inhibitors (risk of hypertensive crisis)
Precautions
Monitor blood pressure, liver function tests, and hemoglobin/hematocrit
Use with caution in patients with depression or Parkinson’s disease
Gradually taper if discontinuing therapy to avoid rebound hypertension
Drug Interactions
MAO inhibitors – risk of hypertensive crisis
Other antihypertensives – additive hypotensive effect
Iron supplements – may reduce absorption if taken simultaneously
Pregnancy & Lactation
Preferred antihypertensive in pregnancy. Use with caution during breastfeeding; monitor infant for hypotension or sedation.
Patient Counseling
Take at the same times each day
Do not stop therapy abruptly; taper gradually
Monitor blood pressure regularly
Report jaundice, unusual fatigue, or signs of anemia