Methyldopa

Indications

Hypertension

Dopamet is indicated in Hypertension.

⚠️ Always consult a registered physician before taking any medicine.

Pharmacology

Methyldopa, also known as α-methyldopa, is a centrally acting sympatholytic agent and an antihypertensive medicine. It is chemically related to DOPA (3,4-dihydroxyphenylalanine) and is a prodrug, meaning it must first be converted in the body into an active metabolite before it can produce its effects. It works by acting as an agonist at alpha(α)-2 adrenergic receptors, which suppresses outgoing adrenergic nerve signals and reduces vasoconstrictor activity, thereby lowering blood pressure. Methyldopa occurs as two isomers, D-α-methyldopa and L-α-methyldopa, of which the L-form is the biologically active one.

Methyldopa was first introduced in 1960 as an antihypertensive agent and was found to be particularly useful in certain groups of patients, including pregnant women and those with impaired kidney function. Over time, it has largely been superseded by newer antihypertensive medicines that are better tolerated, though it is still prescribed today, either alone or in combination with hydrochlorothiazide. An intravenous form of methyldopa is also available and is used to control blood pressure when oral treatment is not practical, as well as to manage hypertensive crises.

Pregnancy & Breastfeeding

Pregnancy category B. Methyldopa passes into breast milk, so it should be used cautiously in mothers who are breastfeeding.

⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.

Dosage Reference

⚠️ Reference ranges from official sources only. Consult your doctor for personalized dosing.

Adults: Adults. Initiation of therapy: the usual starting dose of Methyldopa is 250 mg two or three times a day for the first 48 hours. The daily dose may then be increased or decreased, preferably at intervals of not less than two days, until an adequate response is achieved. To minimize sedation, start any dose increase in the evening. When Methyldopa is given to patients already on other antihypertensives, the dose of those agents may need to be adjusted to allow a smooth transition. When Methyldopa is given with antihypertensives other than thiazides, the initial dose of Methyldopa should be limited to 500 mg daily in divided doses; when Methyldopa is added to a thiazide, the thiazide dose need not be changed. Maintenance therapy: the usual daily dose of Methyldopa is 500 mg to 2 g in two to four doses. Although occasional patients have responded to higher doses, the maximum recommended daily dose is 3 g. Tolerance may occasionally develop, usually between the second and third month of therapy. Adding a diuretic or increasing the dose of Methyldopa will frequently restore effective control of blood pressure. A thiazide may be added at any time during Methyldopa therapy and is recommended if therapy has not been started with a thiazide, or if effective control of blood pressure cannot be maintained on 2 g of Methyldopa daily. Methyldopa is largely excreted by the kidney, so patients with impaired renal function may respond to smaller doses. Syncope in older patients may be related to increased sensitivity and advanced arteriosclerotic vascular disease; this may be avoided by using lower doses. Pediatric use: the initial dose is based on 10 mg/kg of body weight daily in two to four doses. The daily dose is then increased or decreased until an adequate response is achieved. The maximum dose is 65 mg/kg or 3 g daily, whichever is less.

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Indications

Pharmacology

Pregnancy & Breastfeeding

Dosage Reference

Side Effects & Interactions

Side Effects

Key Interactions