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(S)-Methyldopa Structural Formulae V.1.svg
Systematic (IUPAC) name
(S)-2-amino-3-(3,4-dihydroxyphenyl)-2-methyl-propanoic acid
Clinical data
AHFS/ monograph
MedlinePlus a682242
  • AU: A
  • US: B
Oral, IV
Pharmacokinetic data
Bioavailability approximately 50%
Metabolism Hepatic
Half-life 105 minutes
Excretion Renal for metabolites
555-30-6 YesY
C02AB02 (racemic)
PubChem CID 38853
DrugBank DB00968 YesY
ChemSpider 35562 N
UNII 56LH93261Y YesY
Chemical data
Formula C10H13NO4
211.215 g/mol
 N (what is this?)  (verify)

Methyldopa (L-α-Methyl-3,4-dihydroxyphenylalanine; Aldomet, Aldoril, Dopamet, Dopegyt, etc.) is an alpha-adrenergic agonist (selective for α2-adrenergic receptors) psychoactive drug used as a sympatholytic or antihypertensive. Its use is now mostly deprecated following the introduction of alternative safer classes of agents. However, it continues to have a role in otherwise difficult to treat hypertension and gestational hypertension (previously known as pregnancy-induced hypertension (PIH)).

It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.[1]

Medical uses[edit]

Methyldopa is used in the clinical treatment of the following disorders:

Side effects[edit]

Methyldopa is capable of inducing a number of adverse side effects, which range from mild to severe. Nevertheless, they are generally mild when the dose is less than 1 gram per day.[2] Side effects may include:


Rebound hypertension via withdrawal on account of tolerance upon the abrupt discontinuation of methyldopa has been reported.[3]

See also[edit]

Mechanism of Action[edit]

Methyldopa has a dual mechanism of action:


Methyldopa exhibits variable absorption from the gastrointestinal tract. It is metabolized in the liver and intestines and is excreted in urine.


When methyldopa was first introduced, it was the mainstay of antihypertensive treatment, but its use has declined on account of relatively severe adverse side effects, with increased use of other safer and more tolerable agents such as alpha blockers, beta blockers, and calcium channel blockers. Nonetheless, one of methyldopa's still current indications is in the management of pregnancy-induced hypertension (PIH), as it is relatively safe in pregnancy compared to many other antihypertensives which may affect the fetus.


  1. ^ "WHO Model List of EssentialMedicines". World Health Organization. October 2013. Retrieved 22 April 2014. 
  2. ^ British National Formulary 56. September 2008. pp. 95–96. ISBN 978-0-85369-778-7. 
  3. ^ Methyldopa (PIM 342)