methyldopa

Brand names: Aldomet®M Dopa™

Chemical formula:

Drug Forms:
• Methyldopa injection (below)
• Methyldopa Oral tablet
• Methyldopate Hydrochloride Solution for injection

Español:
• Inyección de metildopa
• Metildopa, Tableta oral
• Clorhidrato de Metildopa, Solución para inyección

Methyldopa injection

What is methyldopa injection?

METHYLDOPA (Aldomet®) is an antihypertensive. Methyldopa affects nerve centers in the brain that control blood vessels. As blood vessels relax, methyldopa relieves high blood pressure (hypertension). Methyldopa injection also treats high blood pressure emergency (hypertensive crisis). Generic methyldopa injections are available.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
• anemia
• depression or mental disorders
• heart or blood vessel disease
• kidney disease
• liver disease
• Parkinson's disease
• pheochromocytoma
• an unusual or allergic reaction to methyldopa, other medicines, foods, dyes, or preservatives
• pregnant or trying to get pregnant
• breast-feeding

How should I use this medicine?

Methyldopa is for infusion into a vein. It is usually given by a health care professional in a hospital or clinic setting.

What if I miss a dose?

What drug(s) may interact with methyldopa?

• hawthorn
• iron salts
• medicines for colds and breathing difficulties
• medicines for high blood pressure
• medicine for mental depression
• monoamine oxidase inhibitors (Azilect®, Eldepryl®, Emsam®, Marplan®, Nardil®, Parnate®, Zelapar™)
• some medications for Parkinson's disease, such as entacapone, levodopa or tolcapone
• tolbutamide
• water pills

Tell your prescriber or health care professional about all other medicines you are taking, including non-prescription medicines, nutritional supplements, or herbal products. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way your medicine works. Check with your health care professional before stopping or starting any of your medicines.

What should I watch for while taking methyldopa?

As soon as your blood pressure is properly controlled your prescriber or health care professional may transfer you to either tablets or oral suspension.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how methyldopa affects you. To avoid dizzy or fainting spells, do not stand or sit up quickly, especially if you are an older person. Alcohol can make you more drowsy and dizzy. Avoid alcoholic drinks.

Your mouth may get dry. Chewing sugarless gum or sucking hard candy, and drinking plenty of water will help.

What side effects may I notice from receiving methyldopa?

Side effects that you should report to your prescriber or health care professional as soon as possible:
• chest pain
• black, sore tongue
• dark yellow or brown urine
• depression
• difficulty sleeping, nightmares
• fever (usually within the first 3 months of treatment)
• slow heartbeat
• stomach pain
• swelling of the feet or legs
• unusual weakness or tiredness
• yellowing of the eyes or skin

Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):
• breast enlargement (men or women)
• diarrhea
• dizziness or lightheadedness
• drowsiness
• dry mouth
• headache
• menstrual irregularity
• nausea, vomiting
• numbness or tingling in hands or feet
• sexual difficulties (decreased sexual desire or impotence)
• skin rash
• stuffy nose
• unusual breast milk production

Where can I keep my medicine?

Keep out of the reach of children.

Store at room temperature below 30 degrees C (86 degrees F); do not freeze. Keep container tightly closed. Throw away any unused medicine after the expiration date.

Last updated: 7/1/2002

Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.

A drug used in the treatment of high blood pressure.

The noun has one meaning:

Meaning #1: antihypertensive drug (trade name Aldomet) used in the treatment of high blood pressure
  Synonyms: alpha methyl dopa, Aldomet

Methyldopa
Systematic (IUPAC) name
(S)-2-amino-3-(3,4-dihydroxyphenyl)-2-methyl-propanoic acid
Identifiers
CAS number	555-30-6
ATC code	C02AB01
PubChem	4138
DrugBank	APRD01106
Chemical data
Formula	C10H13NO4
Mol. mass	211.215 g/mol
Pharmacokinetic data
Bioavailability	approximately 50%
Metabolism	Hepatic
Half life	105 minutes
Excretion	Renal for metabolites
Therapeutic considerations
Pregnancy cat.	a drug of choice in PIH
Legal status	℞ Prescription only
Routes	Oral, IV
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Methyldopa (L-α-Methyl-3,4-dihydroxyphenylalanine; Aldomet, Aldoril, Dopamet, Dopegyt, etc) is a psychoactive drug used as a sympatholytic or antihypertensive. Its use is now deprecated following introduction of alternative safer classes of agents. However, it continues to have a role in otherwise difficult to treat hypertension and gestational hypertension (also known as pregnancy-induced hypertension (PIH)).

Contents 1 Indications 2 Pharmacology 3 Pharmacokinetics 4 History 5 Side Effects 5.1 Rebound / Withdrawal 6 See also 7 References

Indications

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

• High blood pressure (HBP) or hypertension (HTN)
• Preeclampsia and eclampsia or hypertensive disorder of pregnancy (HDP)
• Gestational hypertension (GH) or pregnancy-induced hypertension (PIH)

Pharmacology

Methyldopa has a dual mechanism of action:

• It is a competitive inhibitor of the enzyme DOPA decarboxylase, also known as aromatic L-amino acid decarboxylase, which converts L-DOPA into dopamine, and subsequently norepinephrine (noradrenaline) and epinephrine (adrenaline). This inhibition results in reduced dopaminergic and adrenergic neurotransmission in the peripheral nervous system. This effect may lower blood pressure and cause and central nervous system effects such as depression, anxiety, apathy, anhedonia, and parkinsonism.

• It is converted to α-methylnorepinephrine, an agonist of presynaptic central nervous system α₂-adrenergic receptors. Activation of these receptors in the brainstem appears to inhibit sympathetic nervous system output and lower blood pressure.

Pharmacokinetics

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

History

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.

Side Effects

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.^[1] Side effects may include:

• Psychological
  • Depression and/or even suicidal ideation, as well as nightmares
  • Apathy and/or anhedonia, as well as dysphoria
  • Anxiety, especially of the social anxiety variant
  • Decreased alertness, awareness, and wakefulness
  • Impaired attention, focus, and concentration
  • Decreased desire, drive, and motivation
  • Fatigue or lethargy and/or malaise or lassitude
  • Sedation or drowsiness and/or somnolence or sleepiness
  • Agitation or restlessness
  • Cognitive and memory impairment
  • Derealization and/or depersonalization, as well as mild psychosis
  • Sexual dysfunction including impaired libido, desire, and drive

• Physiological
  • Dizziness, lightheadedness, or vertigo
  • Miosis or pupil constriction
  • Xerostomia or dry mouth
  • Gastrointestinal disturbances such as diarrhea and/or constipation
  • Headache or migraine
  • Myalgia or muscle aches, arthralgia or joint pain, and/or paresthesia ("pins and needles")
  • Restless legs syndrome (RLS)
  • Parkinsonian symptoms such as muscle tremors, rigidity, hypokinesia, and/or balance or postural instability
  • Akathisia, ataxia, dyskinesia as well as even tardive dyskinesia, and/or dystonia
  • Bell's palsy or facial paralysis
  • Sexual dysfunction consisting of impaired erectile dysfunction and/or anorgasmia
  • Hyperprolactinemia or excess prolactin, gynecomastia ("man boobs") or breast enlargement in males, and/or amenorrhoea or absence of menstrual cycles in females
  • Bradycardia or decreased heart rate
  • Hypotension or decreased blood pressure (though this may also be considered a therapeutic benefit)
  • Orthostatic hypotension (also known as postural hypotension)
  • Hepatitis, hepatotoxicity, or liver dysfunction or damage
  • Pancreatitis or inflammation of the pancreas
  • Haemolytic anaemia or deficiency in red blood cells (RBCs)
  • Myelotoxicity or bone marrow suppression, potentially leading to thrombocytopenia or blood platelet deficiency and/or leukopenia or white blood cell (WBC) deficiency
  • Hypersensitivity such as lupus erythematosus, myocarditis, and/or pericarditis
  • Lichenoid reactions such as skin lesions and/or rashes

Rebound / Withdrawal

Rebound hypertension via withdrawal on account of tolerance upon the abrupt discontinuation of methyldopa has been reported.^[2]

See also

• D-DOPA (Dextrodopa)
• L-DOPA (Levodopa; Sinemet, Parcopa, Atamet, Stalevo, Madopar, Prolopa, etc)
• L-DOPS (Droxidopa)
• Dopamine (Intropan, Inovan, Revivan, Rivimine, Dopastat, Dynatra, etc)
• Norepinephrine (Noradrenaline; Levophed, etc)
• Epinephrine (Adrenaline; Adrenalin, EpiPed, Twinject, etc)

References

1. ^ British National Formulary 56. September 2008. p. 95–96. ISBN 978-0-85369-778-7. 
2. ^ Methyldopa (PIM 342)

v • d • e Sympatholytic (and closely related) antihypertensives (C02) Sympatholytics (antagonize α-adrenergic vasoconstriction) Central α2 agonist Clonidine • Guanfacine • Methyldopa # Guanidine derivatives: Betanidine • Guanethidine • Guanoxan • Debrisoquine • Guanoclor • Guanazodine • Guanoxabenz Imidazoline receptor agonist Moxonidine • Rilmenidine Ganglion-blocking/nicotinic antagonist Mecamylamine • Trimethaphan Peripheral Indirect MAOI Pargyline Adrenergic uptake inhibitor Rescinnamine • Reserpine Tyrosine hydroxylase inhibitor Metirosine Direct α1 blockers Prazosin • Indoramin • Trimazosin • Doxazosin • Urapidil Non-selective α blocker Phentolamine Other antagonists Serotonin antagonist Ketanserin Endothelin antagonist (for PH) dual (Bosentan) • selective (Ambrisentan, Sitaxentan) #WHO-EM. ‡Withdrawn from market. CLINICAL TRIALS: †Phase III. §Never to phase III

v • d • e Dopaminergics Receptor Ligands Agonists Benzazepines: 6-Br-APB • Fenoldopam • SKF-38,393 • SKF-77,434 • SKF-81,297 • SKF-82,958 • SKF-83,959; Ergot-derivatives: Bromocriptine • Cabergoline • Dihydroergocryptine • Lisuride • LSD • Pergolide; Dihydrexidine-derivatives: 2-OH-NPA • A-86,929 • Dihydrexidine • Dinapsoline • Dinoxyline • Doxanthrine; Morphine-derivatives: Apomorphine • Propylnorapomorphine; Piperazines: ABT-724 • Aripiprazole • Piribedil • WAY-100,635; Others: 7-OH-DPAT • 8-OH-PBZI • A-68,930 • A-77,636 • A-412,997 • ABT-670 • Amantadine • Aplindore • CY-208,243 • Memantine • PD-128,907 • PF-219,061 • Pramipexole • Pukateine • Quinpirole • RDS-127 • Rimantadine • Ropinirole • Rotigotine • SKF-89145 • SKF-89626 Antagonists Typical Antipsychotics: Acepromazine • Azaperone • Benperidol • Bromperidol • Clopenthixol • Chlorpromazine • Chlorprothixene • Droperidol • Flupentixol • Fluphenazine • Fluspirilene • Haloperidol • Loxapine • Mesoridazine • Methotrimeprazine • Molindone • Penfluridol • Perazine • Periciazine • Perphenazine • Pimozide • Prochlorperazine • Promazine • Sulforidazine • Thioridazine • Thiothixene • Trifluoperazine • Triflupromazine • Trifluperidol • Zuclopenthixol; Atypical Antipsychotics: Amisulpride • Asenapine • Clozapine • Iloperidone • Melperone • Olanzapine • Paliperidone • Perospirone • Quetiapine • Risperidone • Sertindole • Sulpiride • Ziprasidone • Zotepine; Antiemetics: AS-8112 • Alizapride • Bromopride • Clebopride • Domperidone • Metoclopramide • Thiethylperazine; Others: Amoxapine • Blonanserin • Buspirone • Butaclamol • N-Ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline • Ecopipam • Eticlopride • Fananserin • Mosapramine • Nafadotride • Nemonapride • Nuciferine • Raclopride • Remoxipride • SB-277,011-A • SCH-23,390 • SKF-83,566 • Spiperone • Spiroxatrine • Stepholidine • Tetrahydropalmatine • Tiapride • UH-232 • Yohimbine Reuptake Inhibitors Plasmalemmal DAT Inhibitors Piperazines: DBL-583 • GBR-12,935 • Nefazodone • Vanoxerine; Piperidines: BTCP • Desoxypipradrol • Dextromethylphenidate • Ethylphenidate • Methylnaphthidate • Methylphenidate • Phencyclidine • Pipradrol; Pyrrolidines: Diphenylprolinol • Methylenedioxypyrovalerone (MDPV) • Naphyrone • Prolintane • Pyrovalerone; Tropanes: β-CPPIT • Altropane • Brasofensine • CFT • Cocaine • Dichloropane • Difluoropine • FE-β-CPPIT • FP-β-CPPIT • Ioflupane (123I) • Iometopane • RTI-112 • RTI-113 • RTI-121 • RTI-126 • RTI-150 • RTI-177 • RTI-336 • Tenocyclidine • Tesofensine • Troparil • Tropoxane • WF-11 • WF-23 • WF-31 • WF-33; Others: Amfonelic Acid • Amineptine • Benzatropine • Bromantane • BTQ • BTS-74,398 • Bupropion (Amfebutamone) • Diclofensine • Dimethocaine • Dizocilpine • DOV-102,677 • DOV-21,947 • DOV-216,303 • Etybenzatropine • Fencamine • Fencamfamine • GYKI-52,895 • Indatraline • Ketamine • Lefetamine • LR-5182 • Manifaxine • Medifoxamine • Mesocarb • Nefopam • Nomifensine • NS-2359 • O-2172 • Propylamphetamine • Radafaxine • SEP-225,289 • SEP-227,162 • Sibutramine • Tametraline • Tripelennamine TRPC6 Activators Adhyperforin • Hyperforin Vesicular VMAT Inhibitors Deserpidine • Ibogaine • Reserpine • Tetrabenazine Releasing Agents Oxazolines: 4-Methylaminorex (4-MAR, 4-MAX) • Aminorex • Clominorex • Cyclazodone • Fenozolone • Fluminorex • Pemoline • Thozalinone; Phenethylamines (also Amphetamines, Cathinones, Phentermines, etc): 2-Hydroxyphenethylamine (2-OH-PEA) • 4-Methylamphetamine (4-MA) • 4-Methylmethamphetamine (4-MMA) • α-Ethylphenethylamine (α-Et-PEA) • Alfetamine • Amphetamine (Dextroamphetamine, Levoamphetamine) • Amphetaminil • Amfepentorex • β-Methylphenethylamine (β-Me-PEA) • Benzodioxolylbutanamine (BDB) • Benzodioxolylhydroxybutanamine (BOH) • Benzphetamine • Buphedrone • Butylone • Cathine • Cathinone • Clobenzorex • Clortermine • Diethylcathinone (Diethylpropion, Amfepramone) • Dibutylone • Dimethoxyamphetamine (DMA) • Dimethoxymethamphetamine (DMMA) • Dimethylamphetamine • Dimethylcathinone (Dimethylpropion, Metamfepramone) • Ethcathinone (Ethylpropion) • Ethylamphetamine • Ethylbenzodioxolylbutanamine (EBDB) • Ethylone • Fenethylline • Fenproporex • Flephedrone • Fludorex • Furfenorex • Hordenine • Indanorex • Indanylamphetamine (IAP) • Lophophine (Homomyristicylamine) • Mefenorex • Mephedrone • Methamphetamine (Desoxyephedrine, Methedrine; Dextromethamphetamine, Levomethamphetamine) • Methcathinone (Methylpropion) • Methedrone • Methoxymethylenedioxyamphetamine (MMDA) • Methoxymethylenedioxymethamphetamine (MMDMA) • Methylbenzodioxolylbutanamine (MBDB) • Methylenedioxyamphetamine (MDA; Tenamfetamine) • Methylenedioxyethylamphetamine (MDEA) • Methylenedioxyhydroxyamphetamine (MDOH) • Methylenedioxymethamphetamine (MDMA) • Methylenedioxymethylphenethylamine (MDMPEA; Homarylamine) • Methylenedioxyphenethylamine (MDPEA; Homopiperonylamine) • Methylone • Naphthylamphetamine (NAP) • Ortetamine • Oxaflozane • Parabromoamphetamine (PBA) • Parachloroamphetamine (PCA) • Parafluoroamphetamine (PFA) • Parafluoromethamphetamine (PFMA) • Parahydroxyamphetamine (PHA) • Paraiodoamphetamine (PIA) • Paramethoxyamphetamine (PMA) • Paramethoxyethylamphetamine (PMEA) • Paramethoxymethamphetamine (PMMA) • Paredrine (Norpholedrine, Oxamphetamine) • Phendimetrazine • Phenethylamine (PEA) • Phenmetrazine • Pholedrine • Phenpromethamine • Propylamphetamine • Tiflorex (Flutiorex) • Tyramine (TRA) • Xylopropamine • Zylofuramine; Piperazines: 2,5-Dimethoxy-4-bromobenzylpiperazine (2C-B-BZP) • Benzylpiperazine (BZP) • Methoxyphenylpiperazine (MeOPP; Paraperazine) • Methylbenzylpiperazine (MBZP) • Methylenedioxybenzylpiperazine (MDBZP; Piperonylpiperazine); Others: 2-Aminoindane (2-AI) • 2-Aminotetralin (2-AT) • 4-Benzylpiperidine (4-BP) • Clofenciclan • Cyclopentamine • Cypenamine • Cyprodenate • Feprosidnine • Gilutensin • Heptaminol • Hexacyclonate • Isometheptene • Methylhexanamine • Octodrine • Phthalimidopropiophenone • Propylhexedrine (PHX) • Tuaminoheptane (Tuamine) Enzyme Inhibitors Anabolism PAH Inhibitors 3,4-Dihydroxystyrene TH Inhibitors 3-Iodotyrosine • Aquayamycin • Bulbocapnine • Metirosine • Oudenone AAAD / DDC Inhibitors Benserazide • Carbidopa • Methyldopa Catabolism MAO Inhibitors (MAOIs) Nonselective: Iproclozide • Iproniazid • Isocarboxazid • Nialamide • Phenelzine • Pheniprazine • Tranylcypromine; MAO-A Selective: Befloxatone • Brofaromine • Cimoxatone • Clorgiline • Harmala Alkaloids • Minaprine • Moclobemide • Pirlindole • Toloxatone • Tyrima; MAO-B Selective: Lazabemide • Pargyline • Rasagiline • Selegiline COMT Inhibitors Entacapone • Tolcapone DBH Inhibitors Disulfiram • Nepicastat • Tropolone Others Precursors L-Phenylalanine → L-Tyrosine → L-DOPA (Levodopa) Cofactors Ferrous Iron (Fe2+) • Tetrahydrobiopterin • Vitamin B3 (Niacin, Nicotinamide → NADPH) • Vitamin B6 (Pyridoxine, Pyridoxamine, Pyridoxal → Pyridoxal Phosphate) • Vitamin B9 (Folic Acid → Tetrahydrofolic Acid) • Vitamin C (Ascorbic Acid) • Zinc (Zn2+) Others Activity Enhancers: Benzofuranylpropylaminopentane (BPAP) • Phenylpropylaminopentane (PPAP)

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