Acute overdosage may produce acute hypotension with other responses attributable to brain and gastrointestinal malfunction (excessive sedation, weakness, bradycardia, dizziness, lightheadedness, 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. Otherwise, management includes special attention to cardiac rate and output, blood volume, electrolyte balance, paralytic ileus, urinary function and cerebral activity.

Sympathomimetic drugs [e.g., levarterenol, epinephrine, ARAMINE¹ (Metaraminol Bitartrate)] may be indicated. Methyldopa is dialyzable. The degree to which hydrochlorothiazide is removed by hemodialysis has not been established. The oral LD₅₀ of methyldopa is greater than 1.5 g/kg in both the mouse and the rat. The oral LD₅₀ of hydrochlorothiazide is greater than 10 g/kg in the mouse and rat.

ALDORIL (methyldopa-hydrochlorothiazide) 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 anuria
• with hypersensitivity to methyldopa, or to hydrochlorothiazide or other sulfonamide-derived drugs
• on therapy with monoamine oxidase (MAO) inhibitors.

Last reviewed on RxList: 4/30/2009
This monograph has been modified to include the generic and brand name in many instances.