ferrous sulfate
Brand names: Feosol, Fer-In-Sol
Ferrous sulfate is an iron supplement. It helps increase iron levels in your body.
What it does
This medicine is used to relieve hot flashes that occur with headaches.
Common side effects
Fatigue, Diarrhea, Nausea
Key warnings
There are no boxed warnings for this medication.
How It Works
Ferrous sulfate provides iron, which is needed to make red blood cells. Red blood cells carry oxygen throughout your body. By increasing iron levels, this medicine helps your body function properly.
How to Take It
Adults and children should dissolve 5 pellets under the tongue. Do this 3 times a day when symptoms start. Continue until your symptoms get better, or follow your doctor's directions.
Pregnancy & Breastfeeding
Talk to your doctor before taking this medicine if you are pregnant or breastfeeding. They can help you decide if it is right for you.
Missed Dose
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store at room temperature away from moisture and heat.
Side Effects (from patient reports)
Based on 24,449 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 47,788 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1995–2025.
Total Reports
47,788
Death-Related Reports
5,418
Hospitalization Reports
20,748
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | FATIGUE | 3,325 |
| 2 | DIARRHOEA | 3,100 |
| 3 | NAUSEA | 2,746 |
| 4 | DYSPNOEA | 2,724 |
| 5 | DEATH | 2,345 |
| 6 | OFF LABEL USE | 2,306 |
| 7 | ACUTE KIDNEY INJURY | 2,070 |
| 8 | ANAEMIA | 1,967 |
| 9 | PNEUMONIA | 1,944 |
| 10 | HEADACHE | 1,922 |
| 11 | ASTHENIA | 1,919 |
| 12 | PAIN | 1,891 |
| 13 | DIZZINESS | 1,857 |
| 14 | VOMITING | 1,780 |
| 15 | FALL | 1,771 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
There are no boxed warnings for this medication.
Known Drug Interactions
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.
Mechanism: 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.
Drug or Drug Class Effect Phosphate Binders (e.g., calcium carbonate, ferrous sulfate, sevelamer, lanthanum) Phosphate binders may bind to levothyroxine. Drug or Drug Class Effect Phosphate Binders (e.g., calcium carbonate, ferrous sulfate, sevelamer, lanthanum) Phosphate binders may bind to levothyroxine.
Mechanism: Ferrous sulfate can stick to levothyroxine in your stomach, which prevents your body from absorbing the thyroid medicine correctly.
What to do: Take these two medications at least four hours apart to make sure your thyroid medicine works as it should.
Common Questions
What is ferrous sulfate used for?
How often should I take this medicine?
Can children take this medicine?
What should I do if my symptoms don't improve?
Can I take this medicine with food?
Are there any serious side effects I should watch out for?
Is it safe to take this medicine while pregnant?
What do I do if I miss a dose?
How should I store this medicine?
Can I take this with other medications?
What are the common side effects of ferrous sulfate?
Does ferrous sulfate interact with other medications?
What drug class is ferrous sulfate?
Is ferrous sulfate safe during pregnancy?
Has ferrous sulfate been recalled?
Active Recalls
CGMP Deviations: Firm went out of business and could no longer continue stability studies.
Akorn, Inc.
Related Medications in Iron Supplement
Other drugs grouped near ferrous sulfate — same-class peers and common alternatives.
ascorbic acid
Vitamin C
This medicine is a Vitamin C supplement.
Compare with ferrous sulfate →
biotin
Vitamin B7
Dialyvite with Zinc is a prescription vitamin supplement.
Compare with ferrous sulfate →
calcitriol
Rocaltrol
Calcitriol is a form of vitamin D that helps your body absorb and use calcium.
Compare with ferrous sulfate →
calcium carbonate
Tums, Caltrate
Calcium carbonate is a medicine that can relieve heartburn and upset stomach.
Compare with ferrous sulfate →
cholecalciferol
Vitamin D3
PNV-DHA is a multivitamin with minerals and essential fatty acids.
Compare with ferrous sulfate →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Pain Relievers Compared
NSAIDs vs acetaminophen — which OTC pain reliever to use
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
Related Health & Safety Data
🩺 Find a Doctor
Search prescribers for Iron Supplement
🏨 Hospital Quality
CMS hospital ratings, safety scores & patient outcomes
💊 Supplement Data
NIH DSLD — check supplement ingredients & label claims
🍽️ Food Safety Alerts
FDA recalls, inspections & outbreak investigations
⚠️ Product Recalls
FDA, CPSC & NHTSA recall search
💉 Procedure Costs
Medicare procedure pricing for 9,297 procedures
What the FDA Data Shows for ferrous sulfate
The FDA label for ferrous sulfate (sold under brand names such as Feosol, Fer-In-Sol) classifies it as an over-the-counter product in the Iron Supplement class. This medicine is used to relieve hot flashes that occur with headaches. Official labeling lists 7 commonly reported side effects, including Fatigue, Diarrhea, Nausea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 24,449 voluntary reports. The database also lists 2 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. Acquisition-cost data is surveyed weekly by CMS and updated as manufacturers report changes.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history (currently 1 recall record on file), and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: July 21, 2025
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages