Drug General Information (ID: DDIMU32JIS)
Drug Name			Methyldopa		Drug Info		Ferrous fumarate		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antihypertensive Agents				Iron Supplement
Structure

Mechanism of Methyldopa-Ferrous fumarate Interaction (Severity Level: Moderate)
Complex formation Click to Show/Hide Mechanism Graph
Drug Name		Methyldopa				Ferrous fumarate
Mechanism		Binds to polyvalent cations				Polyvalent cations
Key Mechanism Factor 1
		Factor Name		Chelation
		Factor Description		Chelation is a direct drug interaction that usually involves the formation of dimers or trimers, resulting in larger complexes and poorer absorption.
Mechanism Description		Decreased absorption of Ferrous fumarate due to formation of complexes caused by Methyldopa

Recommended Action
Management		Until more information is available, patients receiving methyldopa in combination with iron-containing products should be advised to separate the times of administration by as much as possible. Patients should be monitored closely for altered hypertensive effect and methyldopa dosage increased as necessary. Selection of an alternative antihypertensive therapy may be necessary.

References
1	Campbell N, Paddock V, Sundaram R "Alteration of methyldopa absorption, metabolism, and blood pressure control caused by ferrous sulfate and ferrous gluconate." Clin Pharmacol Ther 43 (1988): 381-6. [PMID: 3356082]
2	Campbell NR, Campbell RR, Hasinoff BB "Ferrous sulfate reduces methyldopa absorption: methyldopa: iron complex formation as a likely mechanism." Clin Invest Med 6 (1990): 329-32. [PMID: 2078911]
3	Campbell NR, Hasinoff BB "Iron supplements: a common cause of drug interactions." Br J Clin Pharmacol 31 (1991): 251-5. [PMID: 2054263]