DAWADOPA 250MG TABLETS

Indications

• Hypertension
• Pregnancy-induced hypertension (Gestational hypertension)
• Chronic hypertension in pregnancy

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations.

Adults: Refer to the BNF for specific dosing recommendations.

Mechanism of action

Methyldopa is converted in the body to alpha-methyl norepinephrine, which stimulates alpha-2 adrenergic receptors in the central nervous system. This action leads to a decrease in sympathetic outflow from the central nervous system, resulting in reduced peripheral vascular resistance, heart rate, and blood pressure.

Pharmacodynamics

Methyldopa produces a decrease in blood pressure primarily through its central effects, resulting in vasodilation. It does not significantly affect renal blood flow or glomerular filtration rate, making it a safer option for patients with concurrent renal issues. Its effects can take several hours to become apparent, but it has a sustained antihypertensive effect.

Pharmacokinetics

Methyldopa is well absorbed from the gastrointestinal tract after oral administration. It undergoes extensive first-pass metabolism in the liver, and its bioavailability is about 25%. The drug is distributed into various tissues, including the brain, and is metabolized mainly by conjugation to form alpha-methyl-dopa glucuronide. Methyldopa and its metabolites are excreted primarily via the kidneys. The plasma half-life is approximately 2 hours, though the antihypertensive effects can last longer.

Contra-indications

• Hypersensitivity to methyldopa or any component of the formulation
• Active liver disease or liver impairment
• Severe renal impairment
• Concurrent use of monoamine oxidase inhibitors (MAOIs)

Adverse effects

• Drowsiness
• Dry mouth
• Dizziness
• Fatigue
• Orthostatic hypotension
• Hepatotoxicity
• Hemolytic anemia
• Positive Coombs' test
• Depression
• Nasal congestion

Interactions

• Alcohol may enhance the sedative effects of methyldopa
• Antihypertensives may have additive effects when used with methyldopa
• Iron supplements may reduce the absorption of methyldopa
• Tricyclic antidepressants may antagonize the antihypertensive effect of methyldopa

Precautions

• Monitor liver function tests regularly during treatment
• Exercise caution in patients with a history of depression
• Withdrawal should be gradual to prevent rebound hypertension
• Use with caution in patients with a history of heart disease or renal impairment

Pregnancy

Methyldopa is generally considered safe to use during pregnancy and is often prescribed for hypertension in pregnant women.

Breast-feeding

Methyldopa is excreted in breast milk. Caution is advised when administering to nursing mothers.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Tablets (250 mg, 500 mg)
• Injection (100 mg/ml)