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Dopatab M
Composition
Methyldopa equivalent to Anhydrous Methyldopa 125 mg or 250 mg per tablet.
Actions and Pharmacology
Exact mechanism of antihypertensive actions is currently thought to involve stimulation of central alpha-adrenergic receptors by a metabolite, alpha-methytnorepinephrine, thus inhibiting sympathetic outflow to the heart, kidneys, and peripheral vasculature. Reduced peripheral resistance and plasma renin activity levels may also contribute to its effect. Oral absorption is incomplete and excretion is via urine and faeces.
Indication
For treatment of moderate to severe hypertension.
Contraindication
Not recommended for patients with acute liver disease or phaeochromocytoma.
Precautions
- Evidence of hemolytic anaemia is an indication for discontinuing the drug.
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Positive Coombs' tests may indicate an incompatible cross-match when transfusion is required and an indirect Coombs' test should be carried out.
- Safety for use in pregnancy and lactation has not been established.
- Caution it any kind of surgery or dialysis is required.
Main Side/Adverse Effects
Drowsiness, edema, dry mouth and headache.
Drug Interactions
- Concurrent use with the following drugs is not recommended:
Monoamine oxidase (MAO) inhibitors, levodopa and methotrimeprazine.
- Concurrent use with the following drugs requires careful monitoring:
Alcohol, antihypertensives, general anaesthetics and norepinephrine.
Overdosage
Clinical features . Dizziness, drowsiness, hypotension, tachycardia or bradycardia, hypothermia, extra-pyramidal signs, coma.
Treat overdosage by emesis or gastric lavage, if appropriate; and IV 1-2 mg benztropine if extrapyramidal signs are present.
Dosage and Administration
Adults
Initial - Oral, 250 mg two or three times a day for two days, the dosage then being adjusted as directed.
Maintenance - Oral, 500 mg to 2 g a day, divided into two to four doses, not exceeding 3 g daily.
Children
Oral, initially 10 mg per kg of body weight daily, divided into two to four doses, the dosage then being adjusted as directed, not exceeding 65 mg per kg of body weight or 3 g daily, whichever is less.
Storage
Store below 25°C.
Protect from light.
Presentation/Packing : Film-coated tablet 125 mg x 1000's; 250 mg x 1000's, Blisters 10 x 10's.
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