Methyldopa and Ferrous Sulfate Interaction
Drug interaction information between Methyldopa and Ferrous Sulfate.
Methyldopa and Ferrous Sulfate have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Methyldopa and Ferrous Sulfate. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Iron supplements can prevent the body from absorbing the blood pressure medicine correctly. This means the medicine may not work well enough to control your blood pressure.
What To Do
It is recommended that you do not take these two medications at the same time. Talk to your doctor about the best way to schedule your doses.
FDA Label Information
Several studies demonstrate a decrease in the bioavailability of methyldopa when it is ingested with ferrous sulfate or ferrous gluconate. Coadministration of methyldopa with ferrous sulfate or ferrous gluconate is not recommended.
Methyldopa Also Interacts With
- Carbidopa/Levodopa moderate
- Tranylcypromine moderate
- Lithium minor
- Colestipol minor
- Enalapril minor
Frequently Asked Questions
Can I take Methyldopa and Ferrous Sulfate together?
This is a moderate interaction. It is recommended that you do not take these two medications at the same time. Talk to your doctor about the best way to schedule your doses.
How serious is the interaction between Methyldopa and Ferrous Sulfate?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Methyldopa and Ferrous Sulfate interact?
Iron supplements can prevent the body from absorbing the blood pressure medicine correctly. This means the medicine may not work well enough to control your blood pressure.
Understanding the Methyldopa and Ferrous Sulfate Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Methyldopa belongs to the Central Alpha-2 Agonist class and Ferrous Sulfate belongs to the Iron Supplement class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Iron supplements can prevent the body from absorbing the blood pressure medicine correctly. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Methyldopa has 7 total documented interactions on file in this dataset, and Ferrous Sulfate has 2. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: It is recommended that you do not take these two medications at the same time. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Methyldopa or Ferrous Sulfate based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.