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
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.
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.
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
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
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.
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
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.
Therapeutic class
Centrally Acting Antihypertensive
Storage conditions
Store below 30°C. Keep out of reach of children.
Chemical structure
Methyldopa