Over-the-counter medication · Mineral Supplement
magnesium oxide
Also sold as Mag-Ox. Mag-Ox treats acid indigestion and upset stomach.
Data updated 2026-05-15
- 39,831
- FDA reportsModerately reported
- 1
- InteractionFew interactions
- <$0.01
- Generic price (NADAC)
What the data shows
magnesium oxide (Mag-Ox) is an over-the-counter Mineral Supplement, reported at a middle-of-the-pack volume (39,831 FDA reports), with 1 documented drug interaction.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
magnesium oxide (Mag-Ox) is an over-the-counter Mineral Supplement. Mag-Ox treats acid indigestion and upset stomach.
Magnesium oxide (Mag-Ox) is a mineral supplement. It helps relieve acid indigestion and upset stomach.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
<$0.01/unit
Generic Available
Yes (14 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
NADAC price trail: MAGNESIUM CITRATE SOLUTION
Same CMS presentation as the headline generic unit price above (3 effective dates). Adjacent % compares consecutive NADAC releases for this description only, not a patient out-of-pocket quote. Latest step: +5.6% vs prior release.
| Effective | NADAC / unit | vs prior | NDCs |
|---|---|---|---|
| May 22, 2024 | $0.0067/ML | - | 1 |
| July 17, 2024 | $0.0071/ML | +5.5% | 2 |
| December 18, 2024 | $0.0075/ML | +5.6% | 1 |
What it does
Mag-Ox treats acid indigestion and upset stomach.
Common side effects
Diarrhea
Key warnings
No specific warnings noted. Always follow your prescriber's instructions.
The sections below are summarized in plain English from magnesium oxide's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Mag-Ox contains magnesium oxide, which neutralizes stomach acid. This helps to reduce discomfort caused by excess acid. It provides relief from indigestion and upset stomach.
Side Effects (from patient reports)
Based on 39,831 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for magnesium oxide, by number of reports
- Nausea
Nausea
2,795 reports
- Diarrhoea
Diarrhoea
2,580 reports
- Fatigue
Fatigue
2,419 reports
- Dyspnoea
Dyspnoea
2,054 reports
- Pneumonia
Pneumonia
2,029 reports
- Pyrexia
Pyrexia
1,829 reports
- Vomiting
Vomiting
1,666 reports
- Death
Death
1,601 reports
- Headache
Headache
1,598 reports
- Anaemia
Anaemia
1,465 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for magnesium oxide each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where magnesium oxide sits
magnesium oxide has more FDA adverse-event reports than 69% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is magnesium oxide; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 39,831 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2002–2025.
Total Reports
39,831
Reports Mentioning Death
6,280
15.8% of reports — not proof of cause
Hospitalization Reports
19,832
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | NAUSEA | 2,795 |
| 2 | DIARRHOEA | 2,580 |
| 3 | FATIGUE | 2,419 |
| 4 | DYSPNOEA | 2,054 |
| 5 | PNEUMONIA | 2,029 |
| 7 | PYREXIA | 1,829 |
| 8 | VOMITING | 1,666 |
| 9 | DEATH | 1,601 |
| 10 | HEADACHE | 1,598 |
| 11 | ANAEMIA | 1,465 |
| 12 | PAIN | 1,453 |
| 13 | DECREASED APPETITE | 1,440 |
| 14 | CONSTIPATION | 1,404 |
| 16 | FALL | 1,335 |
| 17 | ASTHENIA | 1,302 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Known Drug Interactions
Antacids and Sucralfate Clinical Impact: Concomitant administration of some antacids (magnesium oxide or aluminum hydroxide) and sucralfate can delay the absorption of naproxen. Intervention: Concomitant administration of antacids such as magnesium oxide or aluminum hydroxide, and sucralfate with naproxen tablets and naproxen sodium tablets is not recommended.
Mechanism: Magnesium oxide can slow down how quickly your body absorbs naproxen into your bloodstream. This might make the naproxen take longer to start working.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
What is Mag-Ox used for?
How many tablets can I take each day?
Can I take Mag-Ox with food?
What should I do if I miss a dose?
How should I store Mag-Ox?
Can I take Mag-Ox if I am pregnant?
What if my symptoms do not improve?
Is Mag-Ox safe for children?
Can I take Mag-Ox with other medications?
What are the possible side effects of Mag-Ox?
What are the common side effects of magnesium oxide?
Does magnesium oxide interact with other medications?
What drug class is magnesium oxide?
What pregnancy or breastfeeding source fields are listed for magnesium oxide?
Related Medications in Mineral Supplement
Other drugs grouped near magnesium oxide - same-class peers and common alternatives.
ascorbic acid
Vitamin C
This medicine is a Vitamin C supplement.
Compare with magnesium oxide →
biotin
Vitamin B7
Dialyvite with Zinc is a prescription vitamin supplement.
Compare with magnesium oxide →
calcitriol
Rocaltrol
Calcitriol is a form of vitamin D that helps your body absorb and use calcium.
Compare with magnesium oxide →
calcium carbonate
Tums, Caltrate
Calcium carbonate is a medicine that can relieve heartburn and upset stomach.
Compare with magnesium oxide →
cholecalciferol
Vitamin D3
PNV-DHA is a multivitamin with minerals and essential fatty acids.
Compare with magnesium oxide →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for magnesium oxide: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 39,831.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 15.77%.
- enoxaparin Δ 0.06 pts · 55,714 reports · Low-Molecular-Weight Heparin 15.70%death share
- furosemide Δ 0.14 pts · 387,984 reports · Loop Diuretic 15.63%death share
- palonosetron Δ 0.18 pts · 3,330 reports · 5-HT3 Receptor Antagonist (Antiemetic) 15.59%death share
- cilostazol Δ 0.19 pts · 5,992 reports · PDE3 Inhibitor (Antiplatelet) 15.95%death share
Medication Guides
Understanding Drug Interactions
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Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
What the FDA Data Shows for magnesium oxide
The FDA label for magnesium oxide (sold under brand names such as Mag-Ox) classifies it as an over-the-counter product in the Mineral Supplement class. Mag-Ox treats acid indigestion and upset stomach. Official labeling lists 1 commonly reported side effect, including Diarrhea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 39,831 voluntary reports. The database also lists 1 documented drug interaction derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of <$0.01.
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, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: October 21, 2025
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
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