Methyldopa is an antihypertensive tablet historically preferred in pregnancy hypertension because it is safe for the fetus. It remains a first-choice option in this setting in many countries.
Also known as: Aldomet
Methyldopa increases lithium levels (reduced renal clearance), with a high risk of lithium toxicity.
Methyldopa reduces renal lithium excretion; toxicity can occur even at usual doses.
Serum lithium (1–2 weeks after starting), tremor, confusion, ataxia.
Coarse tremor, confusion, vomiting, ataxia, drowsiness.
Avoid the combination; if unavoidable, reduce the lithium dose and monitor serum lithium closely.
DailyMed — Methyldopa Tablet and Lithium Carbonate labels (documented combination toxicity): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9e22e1d8-04ec-4b67-92ea-b09c706f2703
Methyldopa plus metoprolol adds hypotensive and bradycardic effects; abrupt beta-blocker withdrawal can cause rebound hypertension.
Both reduce cardiac output and peripheral resistance; rebound results from abrupt beta-blocker withdrawal with increased sympathetic activity.
Orthostatic blood pressure, bradycardia, rebound signs after withdrawal.
Dizziness on standing, pulse < 50 bpm, hypertensive headache.
Never stop the beta-blocker abruptly; monitor blood pressure and pulse in combination.
DailyMed — Methyldopa and Metoprolol Tartrate labels, beta-blocker interactions: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=485f1fdb-6543-4f47-e063-6394a90a2459
Food reduces methyldopa absorption (~35%) but taking it with meals is recommended to reduce gastrointestinal effects; keep intake consistent.
Take with meals, always in the same way (site monograph).
DailyMed — Aldomet (methyldopa): "may be taken with food"; Prontuário 7.3.
Methyldopa causes drug-induced hepatitis — contraindicated in active liver disease and after prior drug hepatitis.
Exclude active liver disease before starting; monitor transaminases in the first months.
Prontuário Terapêutico INFARMED, 7.3 (methyldopa — drug-induced hepatitis, hepatic precaution).
Methyldopa may cause/worsen depression (central effect) — caution in patients with depressive history.
Monitor mood; consider alternative antihypertensives if active depression.
Prontuário Terapêutico INFARMED, 7.3 (methyldopa — depression as adverse reaction).
Contraindicated in phaeochromocytoma — may interfere with catecholamine assays and destabilise blood pressure.
Exclude phaeochromocytoma before starting central antihypertensive therapy.
Prontuário/EMC-UK — methyldopa SmPC 4.3 (phaeochromocytoma).
Methyldopa is the historical reference antihypertensive in pregnancy hypertension, with decades of experience and follow-up of exposed children without long-term adverse effects. NOTE on the source: the Prontuário Annex 1 contains a graphical error on the line "Methyldopa — Contraindicated in pregnancy; See Androgens" — the text belongs to the androgen entry (mesterolone); no reputable source classifies methyldopa as contraindicated, and the Prontuário itself (4.3.1.) describes it as the antihypertensive of choice in pregnancy.
Compatible in all trimesters; usual dose 250–500 mg 2–3×/day. May cause maternal depression — monitor. Continue if indicated postpartum.
Excreted into milk in small amounts; at therapeutic doses generally considered compatible with breastfeeding (EMC-UK).
Prontuário Terapêutico INFARMED — 4.3.1 (Antihypertensives): methyldopa as the antihypertensive of choice in pregnancy; Annex 1 l. 40956 (graphical error documented). EMC-UK (MHRA) — Methyldopa SmPC: https://www.medicines.org.uk/emc/product/2195/smpc (section 4.6).
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Reference central antihypertensive in pregnancy, with proven efficacy and established fetal safety over decades of use; less used outside gestation due to central effects.
Converted in the CNS to α-methylnoradrenaline, a false transmitter stimulating central (brainstem) alpha-2 receptors: reduced sympathetic outflow, peripheral vascular resistance and heart rate; renal and placental flows preserved.
Variable oral absorption (~25–50%, saturable at high doses); peak 2–4 h; maximum antihypertensive effect 6–8 h after the dose. Food does not significantly change absorption extent.
Decarboxylation and hydroxylation in the CNS (dopa decarboxylase and dopamine-β-hydroxylase); renal excretion of unchanged methyldopa (~40–60%) and conjugates. Dialysis removes the drug.
1.5–2 h (plasma); prolonged pharmacological effect (24–48 h) due to persistence of the false transmitter in central stores.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
