[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Centrally acting antihypertensives](https://durgical.com/en/pharmacology/classes/centrally-acting-antihypertensives/) › Methyldopa [Pharmacology](https://durgical.com/en/pharmacology/) · [Centrally acting antihypertensives](https://durgical.com/en/pharmacology/classes/centrally-acting-antihypertensives/) # Methyldopa An older oral blood pressure medicine that acts in the brain. It is still a classic choice for high blood pressure in pregnancy. Updated 2026-11-01 - Class: [Centrally acting antihypertensives](https://durgical.com/en/pharmacology/classes/centrally-acting-antihypertensives/) - Receptor: Alpha-2A adrenergic receptor (through alpha-methylnorepinephrine) - ATC code: C02AB01 - WHO Model List of Essential Medicines Also called: Alpha-methyldopa ◎**Alpha-2A adrenergic receptor (through alpha-methylnorepinephrine)**Methyldopa ⓘ The figure shows noradrenaline bound to the human alpha-2A adrenergic receptor; alpha-methylnorepinephrine, the active metabolite of methyldopa, acts at the same site. **Target in 3D:** Alpha-2A adrenergic receptor (through alpha-methylnorepinephrine). PDB structure 7EJ0 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/7EJ0) · Drag to rotate · pinch to zoom ## Mechanism of action Methyldopa is an analogue of L-dopa. In adrenergic neurons it is converted to alpha-methyldopamine and then alpha-methylnorepinephrine. The metabolite stimulates alpha-2 receptors in the brainstem, reducing sympathetic outflow, so peripheral resistance falls with little change in cardiac output. - Methyldopa is converted to alpha-methylnorepinephrine in neurons - The metabolite stimulates central alpha-2 receptors - Sympathetic outflow and peripheral resistance fall ## Pharmacokinetics **Absorption** Oral; absorption is incomplete and reduced by iron salts **Metabolism** Converted in neurons to its active metabolite; also conjugated as a sulfate **Elimination** Mostly by the kidneys; removed by dialysis **Half-life** Plasma half-life about 105 minutes, but the effect lasts much longer (label) **Onset and duration** Maximum fall in pressure several hours after a dose ## Indications - High blood pressure [Arterial hypertension →](https://durgical.com/en/conditions/arterial-hypertension/) - High blood pressure in pregnancy, including preeclampsia [Preeclampsia →](https://durgical.com/en/conditions/preeclampsia/) ## Adverse effects ### Common - Sedation, mainly at the start or after a dose increase - Headache and weakness - Nasal stuffiness - Orthostatic hypotension and oedema - Positive direct Coombs test ### Serious (rare, important) - Autoimmune haemolytic anaemia - Hepatitis and, rarely, fatal hepatic necrosis - Drug fever in the first weeks - Myocarditis, pericarditis or a lupus-like syndrome - Bone marrow depression ## Contraindications - Active liver disease (acute hepatitis, active cirrhosis) - Liver disorders previously caused by methyldopa - Treatment with MAO inhibitors - Hypersensitivity, including previous methyldopa-related haemolytic anaemia ## Key interactions **Ferrous sulfate or ferrous gluconate** Lower methyldopa bioavailability and poorer blood pressure control **Lithium** Risk of lithium toxicity **MAO inhibitors** Contraindicated combination **Other antihypertensives and anaesthetics** Additive fall in blood pressure ## What is monitored - Blood pressure - Blood count and direct Coombs test before and during treatment - Liver function, especially in the first months - Temperature in the first weeks ## Nursing care - Before: baseline blood count, Coombs test and liver tests. - Warn about drowsiness at the start, so tasks that need alertness are planned around it. - Report fever, jaundice, dark urine, tiredness or pallor (possible hepatitis or haemolysis). - Methyldopa can make urine catecholamine tests read falsely high: tell the laboratory. - Before a transfusion, the blood bank is told the patient takes methyldopa (Coombs test). ## Pregnancy and breastfeeding Used in all trimesters; published experience suggests the possibility of fetal harm is remote (label), which is why it remains a classic antihypertensive in pregnancy. ## Memory aid Methyldopa for Mothers: it Makes a false Messenger (alpha-methylnorepinephrine) and can Make the Coombs test positive. ## Test yourself Think of the answer, then tap the question to see it. ## How does methyldopa lower blood pressure? It is converted to alpha-methylnorepinephrine, which stimulates alpha-2 receptors in the brainstem and reduces sympathetic outflow and peripheral resistance. ## Which laboratory finding appears in some patients on long-term methyldopa? A positive direct Coombs test; a few develop autoimmune haemolytic anaemia, so blood counts are checked. ## In which group of patients is methyldopa still a classic choice? Pregnant women with high blood pressure, because long experience suggests the fetal risk is remote. ## Which common supplement reduces the absorption of methyldopa? Iron salts (ferrous sulfate or gluconate), which lower its bioavailability and blood pressure control. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/methyldopa/) ## Related drugs - [Clonidine](https://durgical.com/en/pharmacology/clonidine/) - [Hydralazine](https://durgical.com/en/pharmacology/hydralazine/) ## Related conditions - [Arterial hypertension](https://durgical.com/en/conditions/arterial-hypertension/) - [Preeclampsia](https://durgical.com/en/conditions/preeclampsia/) [← Back to the class: Centrally acting antihypertensives](https://durgical.com/en/pharmacology/classes/centrally-acting-antihypertensives/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [DailyMed - METHYLDOPA tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9e22e1d8-04ec-4b67-92ea-b09c706f2703) (DailyMed (U.S. National Library of Medicine), 2025); [Methyldopa: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682242.html) (MedlinePlus (U.S. National Library of Medicine), 2017); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=C02AB01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Farmacología básica y clínica (Katzung), cap. 11 (McGraw Hill, 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/methyldopa/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/methyldopa/