Methyldopa

Hypertension.

• Adults : Initiation of Therapy : The usual starting dosage of methyldopa tablets is 250 mg two to three times a day in the first 48 hours
• The daily dosage then may be increased or decreased, preferably at intervals of not less than 2 days, until an adequate response is achieved
• To minimize the sedation, start dosage increases in the evening
• By adjustment of dosage, morning hypotension may be prevented without sacrificing control of afternoon blood pressure
• When methyldopa tablets are given to patients on other antihypertensives, the dose of these agents may need to be adjusted to effect a smooth transition
• When methyldopa tablets are given with anti-hypertensives other than thiazides, the initial dosage of methyldopa tablets should be limited to 500 mg daily in divided doses; when methyldopa tablets are added to a thiazide, the dosage of thiazide need not be changed
• Maintenance of Therapy : The usual daily dosage of methyldopa tablets is 500 mg to 2 g in two to four doses
• Although occasional patients have responded to higher doses, the maximum recommended daily dosage is 3 g
• Once an effective dosage range is attained, a smooth blood pressure response occurs in most patients in 12 to 24 hours
• Since methyldopa has a relatively short duration of action, withdrawal is followed by return of hypertension usually within 48 hours
• This is not complicated by an overshoot of blood pressure
• Occasionally tolerance may occur, usually between the second and third month of therapy. …

• There are no well-controlled clinical trials
• In pediatric patients
• Information on dosing
• In pediatric patients is supported by evidence from published literature regarding the treatment of hypertension
• In pediatric patients. (See DOSAGE AND ADMINISTRATION .)

Of the total number of subjects (1,685) in clinical studies of methyldopa, 223 patients were 65 years of age and over, while 33 patients were 75 years of age and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individual …

Methyldopa is contraindicated in patients: – with active hepatic disease, such as acute hepatitis and active cirrhosis. – with liver disorders previously associated with methyldopa therapy (see WARNINGS ). – with hypersensitivity to any component of this product. – on therapy with monoamine oxidase (MAO) inhibitors.

When methyldopa is used with other antihypertensive drugs, potentiation of antihypertensive effect may occur. Patients should be followed carefully to detect side reactions or unusual manifestations of drug idiosyncrasy. Patients may require reduced doses of anesthetics when on methyldopa. If hypotension does occur during anesthesia, it usually can be controlled by vasopressors. The adrenergic receptors remain sensitive during treatment with methyldopa. When methyldopa and lithium are given concomitantly, the patient should be carefully monitored for symptoms of lithium toxicity. Read the circular for lithium preparations. …

It is important to recognize that a positive Coombs test, hemolytic anemia, and liver disorders may occur with methyldopa therapy. The rare occurrences of hemolytic anemia or liver disorders could lead to potentially fatal complications unless properly recognized and managed. Read this section carefully to understand these reactions. With prolonged methyldopa therapy, 10% to 20% of patients develop a positive direct Coombs test which usually occurs between 6 and 12 months of methyldopa therapy. Lowest incidence is at daily dosage of 1 g or less. This on rare occasions may be associated with hemolytic anemia, which could lead to potentially fatal complications. …

Sedation, usually transient, may occur during the initial period of therapy or whenever the dose is increased. Headache, asthenia, or weakness may be noted as early and transient symptoms. However, significant adverse effects due to methyldopa have been infrequent and this agent usually is well tolerated. The following adverse reactions have been reported and, within each category, are listed in order of decreasing severity. Cardiovascular : Aggravation of angina pectoris, congestive heart failure, prolonged carotid sinus hypersensitivity, orthostatic hypotension (decrease daily dosage), edema or weight gain, bradycardia. …

Pregnancy Teratogenic Effects . Reproduction studies performed with methyldopa at oral doses up to 1000 mg/kg in mice, 200 mg/kg in rabbits and 100 mg/kg in rats revealed no evidence of harm to the fetus. These doses are 16.6 times, 3.3 times and 1.7 times, respectively, the maximum daily human dose when compared on the basis of body weight; 1.4 times, 1.1 times and 0.2 times, respectively, when compared on the basis of body surface area; calcula …

Acute overdosage may produce acute hypotension with other responses attributable to brain and gastrointestinal malfunction (excessive sedation, weakness, bradycardia, dizziness, light-headedness, constipation, distention, flatus, diarrhea, nausea, vomiting). In the event of overdosage, symptomatic and supportive measures should be employed. When ingestion is recent, gastric lavage or emesis may reduce absorption. When ingestion has been earlier, infusions may be helpful to promote urinary excretion. …

Take it when you remember, unless it is nearly time for the next dose. Then skip the missed one. Never take two doses at once to make up for it. Check your leaflet, as some medicines are different.