Methyldopa

Methyl dopa is a widely used oral antihypertensive agent. Methyldopa is analog of L-dopa. Chemically Methyldopa is identified as L-3-(3, 4-dihydroxyphenyl)-2-methylalanine. After crossing the blood-brain barrier, Methyldopa is decarboxylated to produce alpha-methylnorepinephrine. This metabolite stimulates central inhibitory alpha-adrenergic receptors, thereby reducing peripheral resistance and lowering blood pressure.it also may act as a false transmitter, thereby exerting a direct effect on peripheral sympathetic nerves. Blood pressure decreases are greatest when the patient is standing but are also significant when the patient is supine. Postural hypotension has been reported in patients receiving it. It can cause sodium and fluid retention, and tolerance can develop during long-term therapy.

Brands

ALDOPA METHYLDOPA ALDOMET DOPAMAT HYPODOPA ALDOPRESS LISKOMET REGATOP NORMET HYPERGEN BIMET CARA-DOPA CARA-DOPA

Adult Dose

Dose: 250 to 1000 mg
Single Dose: 620 (625)
Frequency: 8 hourly
Route: PO
Instructions:

Neonatal

Dose: 5 to 10 mg/kg
Single Dose: 7.5 (7.5)
Frequency: 6 hourly
Route: Intra Venous
Instructions: -

Paedriatic

Dose: 5 to 0 mg/kg
Single Dose: 2.5 (2.5)
Frequency: 6 hourly
Route: Intra Venous
Instructions: In 2-4 divided dose is 65 mg/kg,

Characteristics

. It is of Synthetic origin and belongs to Phenyl Alanine. It belongs to Alpha-2 adrenergic agonist pharmacological group on the basis of mechanism of action and also classified in Antihypertensive Agents pharmacological group.The Molecular Weight of Methyldopa is 238.20. Its pKa is 2.2, 9.2, 10.6, 12.

Contraindications

Methyldopa is contraindicated in conditions like Hepatic disease,Hypersensitivity,Postural hypotension.

Effects

The severe or irreversible adverse effects of Methyldopa, which give rise to further complications include Thrombocytopenia, Pancreatitis, Granulocytopenia, Depression, Acute colitis.Methyldopa produces potentially life-threatening effects which include Hemolytic anemia, Hepatitis, Myocarditis. which are responsible for the discontinuation of Methyldopa therapy.The signs and symptoms that are produced after the acute overdosage of Methyldopa include Bradycardia, Hypotension, Coma, Dry mouth, Hypothermia, Dizziness, Weakness.The symptomatic adverse reactions produced by Methyldopa are more or less tolerable and if they become severe, they can be treated symptomatically, these include Dizziness, Diarrhea, Fever, Skin rashes, Dry mouth, Sedation, Impotence, Loss of libido, Nasal congestion, Light headedness, Galactorrhea, Eosinophilia, Failure of ejaculation.

Indications

Methyldopa is primarily indicated in conditions like Hypertension, Hypertension in pregnancy, Hypertensive emergencies, Primary hypertension, Renal hypertension, and can also be given in adjunctive therapy as an alternative drug of choice in Postmenupausal flushing.

Interactions

Methyldopa is known to interact with other drugs, the details of drug interactions is as follows:DrugDetailsSeverityOnsetManagementAcrivastineAldesleukinEnhanced hypotensive effect when aldesleukin given with Methyldopa.AlprostadilEnhanced hypotensive effects when alprostadil given with Methyldopa.Amantadine (HCl)Methyldopa has extrapyramidal side effects.ApomorphineAntiparkinsonian effects of Apomorphine possibly antagonized by Methyldopa.BaclofenEnhanced hypotensive effect when Baclofen given with Methyldopa.CabergolineAntiparkinsonian effect of Cabergoline possibly antagonized by Methyldopa.Chlorpromazine (HCl)Chlorpromazine (HCl)DeflazacortDesipramine (HCl)DiazoxideEnhanced hypootensive effect when Diazoxide given with Methyldopa.Doxepin (HCl)FluphenazineFurazolidoneCoadministration results in alteration in blood pressure,hyperexcitability and hallucinations.MajorCoadministration is considered contraindicated.GestodeneHaloperidolIron SaltsLevodopaLevodopa increases the antihypertensive effect of methyldopa and thus increase the risk of hypotension.MinorBlood pressure should be monitor regularly.LithiumMolindoneConcurrent use with Molindone increases certain serious side effects.Noradrenaline (Acid Tartrate)Methyldopa enhanced the pressor effects of norepinephrine results in hypertension.ModerateClosely monitor the blood pressure of patient regularly. If hypertension develop, dicontinue the norepinephrine.PerphenazinePhenylephrine (HCl)ProcarbazineThe combined use of methyldopa and procarbazine may increases sympathetic stimulation in central nervous system result in loss of control on blood pressure, hyperexcitability and hallucination.MajorCoadministration is considered contraindicated. Start treatment with methyldopa after stopping (atleast 14 days) of procarbazine.Pseudoephedrine (HCl)Methyldopa and resperpine increase the afficacy of Pseduoephedrine (HCl)Selegiline (HCl)The combined use of methyldopa and selegiline may increases sympathetic stimulation in central nervous system result in loss of control on blood pressure, hyperexcitability and hallucination.MajorCoadministration is considered contraindicated. Start treatment with methyldopa after stopping (atleast 14 days) of selegiline.Tranylcypromine (Sulphate)Trimipramine (Maleate)Zalcitabine These interactions are sometimes beneficial and sometimes may pose threats to life. Always consult your physician for the change of dose regimen or an alternative drug of choice that may strictly be required.

Interfrence

Positve Coombs test, interfere with cross matching of Blood False +ve results in the Watson-Schwartz Method of Testing for Prophobilinogen Creatinine determination by Alkaline Picrate Method False +ve Urinary Catecholamine in Fluorimetric Method Clinest Tabs give false +ve test of glucose False -ve result of urinary 5-OH indoleacetic acid Colorimetric measurement of serum asparate aminotransferase

Risks

Drug should not be given to patients suffering from Kidney dysfunction, and patients suffering from Liver Malfunction.If prescribing authority justifies the benefits of the drug against the possible damages he/she should reevaluate them and consult the reference material and previous studies.

Storage

Inj Store Below 30°C. Do not Freeze. Oral Susp Store in a well closed container, at room temperature, Below 25°C. Protect from Sunlight and Moisture. Tab Store in a well closed container, Below 40°C.

Warnings

The patient should have Hemoglobin, Hemocrit and ESR assessed before and during Methyldopa therapy because of the risk of the hemolytic anemia. The drug should be used with caution in the patient with hemolytic anemia and autoimmune disease, if present, discontinue the therapy. The drug should be used with caution in the patient with hepatic or renal impairment, pheochromocytoma, and cardiovascular or cerebrovascular insufficiency, major Depression. Methyldopa can cause the sedation, so the patient should be warned that impaired physical coordination and /or reduced mental alertness can affect their ability to operate machinery or drive a vehicle.

Back to List

Any information that appears on this website page is provided for the purpose of general information. This website has been compiled in good faith by HMIS.Online. However, no guarantee is made as to the completeness, validity or accuracy of the information it contains.