Methyldopa

Also indexed as: Aldomet®

Combination drugs: Aldoclor®, Aldoril®

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

Summary of Interactions with Vitamins, Herbs, and Foods
(for details about the summarized interactions, read the full article)

Beneficial May be Beneficial: Depletion or interference—The medication may deplete or interfere with the absorption or function of the nutrient. Taking these nutrients may help replenish them.

Vitamin B12*
Avoid Avoid: Reduced drug absorption/bioavailability—Avoid these supplements when taking this medication since the supplement may decrease the absorption and/or activity of the medication in the body.

Iron
Avoid Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results.

Sodium
Side effect reduction/prevention

None known
Supportive interaction

None known

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 Dietary 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.

Interactions with Foods and Other Compounds

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.