Methyldopa

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Also indexed as:

Aldomet

Combination List

Combination drugs:

• Aldoclor
• Aldoril

Methyldopa is a drug used to lower blood pressure in people with hypertension (high blood pressure).

Herbs

Summary of Interactions for Methyldopa

Depletion or interference	Vitamin B12*
Adverse interaction	Sodium
Side effect reduction/prevention	None known
Supportive interaction	None known
Reduced drug absorption/bioavailability	Iron

An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

Interactions with Supplements

Iron

Iron supplements have been found to decrease methyldopa absorption.^{1, 2} Taking methyldopa two hours before or after iron-containing products can help avoid this interaction.

Vitamin B12

Methyldopa can decrease vitamin B12 levels, thus increasing the risk of vitamin B12 deficiency.³

Sodium

Excess dietary sodium (salt) intake can cause fluid retention and interfere with the blood pressure lowering action of methyldopa.⁴ Reducing the use of table salt and heavily salted foods during methyldopa therapy reduces the likelihood of this interference.

Other Interactions

Food

Food can interfere with methyldopa absorption.⁵ Taking methyldopa one hour before or two hours after eating can prevent this interference.

References

1. Campbell NR, Hasinoff BB. Iron supplements: A common cause of drug interactions. Brit J Clin Pharmacol 1991;31:251-5.
2. Campbell N, Paddock V, Sundaram R. Alteration of methyldopa absorption, metabolism, and blood pressure control caused by ferrous sulfate and gluconate. Clin Pharmacol Ther 1988;43:381-6.
3. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 74.
4. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 171-2 .
5. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 170-1.

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Last Review: 01-21-2009

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