Generic
Methyldopa
6 brands available in the market
At a glance
Methyldopa is a centrally acting antihypertensive used to control high blood pressure (hypertension).
Description
Methyldopa is a centrally acting sympatholytic agent that stimulates alpha-2 adrenergic receptors reducing sympathetic tone and lowering blood pressure. It is a DOPA analog and a prodrug that is converted to an active metabolite. It is considered safe for treating hypertension during pregnancy and is preferred for hypertensive disorders in pregnancy.
Indications
- Hypertension (high blood pressure)
- Hypertension during pregnancy
- Hypertension with renal insufficiency
Therapeutic class
Centrally Acting Antihypertensive
Pharmacological class
Central Sympatholytic
Pharmacology
Methyldopa acts as an agonist at alpha-2 adrenergic receptors, inhibiting adrenergic neuronal outflow and reducing vasoconstrictor adrenergic signals. It is converted to α-methylnorepinephrine in the CNS which stimulates presynaptic α-2 receptors reducing sympathetic nervous system activity.
Mechanism of action
Lowers blood pressure by reducing sympathetic nervous system activity and dilating blood vessels.
Dosage
Adult Dose (Oral):
- Monotherapy: Initial: 250 mg 2-3 times daily for 2 days; adjust at intervals of at least 2 days according to response
- Maintenance: 500-2,000 mg daily
- Maximum: 3,000 mg daily
- Combination therapy: Initial dose should not exceed 500 mg daily
- Elderly: Initial: 125 mg twice daily; gradually increase; Maximum 2,000 mg daily
Child Dose: 10 mg/kg or 300 mg/m² daily (2-4 divided doses); Max: 65 mg/kg or 3,000 mg daily
Renal Dose: CrCl >50 mL/min: q8hr; CrCl 10-50: q8-12hr; CrCl <10: q12-24hr
Administration
- Swallow tablet whole; do not chew, crush or break
- May be taken with or without food
- Take at the same time each day
- Take last dose at bedtime (to minimize sedation)
- Avoid high protein meals (cottage cheese, Swiss cheese, protein powder, eggs, milk)
Missed dose
If you miss a dose, take it as soon as you remember; skip if it's almost time for next dose; do not double the dose.
Side effects
Common Side Effects:
- Dizziness
- Fatigue and sleepiness
- Dry mouth
- Orthostatic hypotension (sudden lowering of BP on standing)
- Headache
- Asthenia (weakness)
Rare Side Effects:
- Angina pectoris, congestive heart failure
- Edema or weight gain
- Bradycardia, pancreatitis
- Hepatitis, jaundice
- Bone marrow depression, leukopenia
- Thrombocytopenia, hemolytic anemia
- Parkinsonism, psychosis or depression
Precautions & warnings
- Caution while driving or operating machinery (may cause drowsiness and dizziness)
- Monitor liver function (inform doctor if jaundice symptoms appear)
- Do not stop abruptly (blood pressure may rise)
- Monitor blood pressure regularly
- Contraindicated in active liver disease
Contraindications
- Active liver disease (acute hepatitis, active cirrhosis)
- Depression
- Concomitant use with MAOIs
- Hypersensitivity to Methyldopa or components
- Liver disorders previously associated with Methyldopa therapy
Drug interactions
- Phenothiazines, TCAs, amphetamines: Reduced hypotensive effects
- Levodopa: Additive hypotensive effects; psychosis may occur
- Oral iron preparations: Reduced absorption and effects
- MAOIs: Risk of severe hypertension (potentially fatal)
- Lithium: Increased toxicity
- General anesthetics: Dose reduction may be required
- Ephedrine: Effect may be reduced
Food interactions
Avoid high protein meals (cottage cheese, Swiss cheese, protein powder, eggs, milk) with Methyldopa. Alcohol should be taken with caution.
Use in pregnancy
Use in Pregnancy (Category B): Considered safe during pregnancy. Animal studies show low or no adverse effects on developing baby. Preferred drug for hypertension during pregnancy.
Pregnancy Category: B — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Safe during breastfeeding. Human studies suggest the drug does not pass into breastmilk in significant amounts and is not harmful to the baby.
Pediatric use
Pediatric dose established: 10 mg/kg daily (2-4 divided doses); Max: 65 mg/kg or 3,000 mg daily.
Geriatric use
Elderly: Initial dose 125 mg twice daily; gradually increase; Maximum 2,000 mg daily. Caution: Syncope may occur.
Renal / hepatic impairment
Renal Impairment: Dose interval adjustment required: CrCl >50: q8hr; CrCl 10-50: q8-12hr; CrCl <10: q12-24hr. Regular blood pressure monitoring recommended.
Hepatic Impairment: Probably unsafe in liver disease - avoid. Consult your doctor.
Overdose effects
Acute overdose may cause acute hypotension, excessive sedation, weakness, bradycardia, dizziness, constipation, diarrhea, nausea, vomiting. Symptomatic and supportive treatment. Recent ingestion: gastric lavage or emesis.
Storage conditions
Store below 30°C. Keep out of reach of children.
Chemical structure
Methyldopa