Food and medicine interaction
Iron supplements and multivitamins with iron and levodopa (in Sinemet and Stalevo) for Parkinson's disease
EstablishedEvidence level: established. Shown in drug labeling or in controlled studies in people.
Last reviewed
What can happen
Iron can reduce how much levodopa the body absorbs. In a randomized crossover study in 8 healthy people, a 325 mg ferrous sulfate tablet cut peak levodopa levels by 55 percent and total exposure by 51 percent.
- Why it happens
- Iron binds (chelates) levodopa in the small intestine, and the bound drug is not absorbed.
- At ordinary food amounts
- The concern is iron tablets and multivitamins with iron, not iron-rich foods at ordinary meal amounts.
What to do
U.S. levodopa labels warn that iron supplements may reduce its effect. Ask your neurologist or pharmacist how to space iron and levodopa, and tell them if your symptoms change after starting iron.
Never stop or change a prescribed medicine without talking to the prescriber.
Common questions
Can I have iron supplements and multivitamins with iron while taking Parkinson's medicines?
U.S. levodopa labels warn that iron supplements may reduce its effect. Ask your neurologist or pharmacist how to space iron and levodopa, and tell them if your symptoms change after starting iron. The concern is iron tablets and multivitamins with iron, not iron-rich foods at ordinary meal amounts.
Sources
- NIH Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals.
- MedlinePlus (U.S. National Library of Medicine). Levodopa and Carbidopa: drug information.
- Campbell NR, Hasinoff B. Ferrous sulfate reduces levodopa bioavailability: chelation as a possible mechanism. Clin Pharmacol Ther. 1989. PMID 2920496.