Methyldopa is a drug used to lower blood pressure in people with hypertension (high blood pressure).
Methyldopa can decrease vitamin B12 levels, thus increasing the risk of vitamin B12 deficiency.1
Iron supplements have been found to decrease methyldopa absorption.2 , 3 Taking methyldopa two hours before or after iron-containing products can help avoid this interaction.
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.
1. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 74.
2. Campbell NR, Hasinoff BB. Iron supplements: A common cause of drug interactions. Brit J Clin Pharmacol 1991;31:251–5.
3. 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.
4. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 171–2 .
Last Review: 05-01-2013
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