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Magnesium Oxide 400 mg Tablet, 120-count — NDC 58657-0120-12 package photo
Label image from the product's FDA listing (DailyMed) — may show a different pack size or an older label revision.

Magnesium Oxide 400 mg Tablet, 120-count — NDC 58657-120-12 (Billing 58657-0120-12)

by Method Pharmaceuticals, LLC · 120 TABLET in 1 BOTTLE

This is a package of 120 tablets of Magnesium Oxide 400 mg Tablet from Method Pharmaceuticals, LLC, marketed since Jul 2018 and currently FDA-listed; retail pharmacies pay about $0.0346 per tablet (NADAC). It is this product's only package size.

NDC 58657-0120-12
🏷️ FDA NDC (as labeled) 58657-120-12 billing pads the product segment with a zero
OTC On market Non-controlled ⇄ Compare with another NDC
🗂️ FDA directory synced Oct 8, 2026 · this listing last changed Oct 8, 2026 · sources: openFDA · FDA label (DailyMed) · FDA Orange & Purple Book · First Databank · CMS NADAC, ASP, Medicare & Medicaid · RxNorm
📋 All sources & update times →

This page is curated, coded, and maintained by

Compiled from public FDA, CMS, DailyMed, NADAC, and related drug data sources. Editorial policy

NDC database record

One package, one record: these facts belong to NDC 58657-120-12 alone.

Record
FDA NDC Directory package listing · Human OTC drug
Code segments
58657 labeler · 120 product · 12 package
Package marketed since
Jul 25, 2018
Sample package
No — commercial package
Listing certified through
Dec 31, 2026
Billing quantity
120 EA per package
Barcode (UPC-A, from the NDC)
3 5865712012 2
Medicaid fills, this package
34,321 prescriptions in the last four reported quarters
FDA record last changed
Oct 8, 2026

Identity & classification

Regulatory identifiers FDA, NLM and CMS codes for this package

FDA NDC (as labeled) 58657-120-12
Product NDC 58657-120
11-digit billing NDC 58657012012
NCPDP billing unit EA — each (per item)
RxCUI 198741
UNII 3A3U0GI71G
Application # M001
SPL Set ID 0af63651-f9d9-43b9-b6f0-4878466a82e6
Established class (EPC) Calculi Dissolution Agent; Osmotic Activity
Mechanism of action Magnesium Ion Exchange Activity
Physiologic effect Increased Large Intestinal Motility; Inhibition Large Intestine Fluid/Electrolyte Absorption; Inhibition Small Intestine Fluid/Electrolyte Absorption
DEA schedule Non-controlled
Marketing category OTC MONOGRAPH DRUG
Marketing status On market
FDA listing status Listed (active directory)
Marketing start 2018-07-25
Route ORAL
Dosage form TABLET
Substance MAGNESIUM OXIDE

Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification

GPI-14 48400020000310
GPI class Magnesium Oxide
GCN Seq No 078687
GCN 45064
HICL code 000609
Ingredient (HICL) Magnesium Oxide
HIC1 code D
Therapeutic class — broad (HIC1) Biliary System/Gastro-Intestinal System
HIC2 code D4
Therapeutic class — intermediate (HIC2) Drugs Acting Principally On The Alimentary Tract
HIC3 code D4B
Therapeutic class — specific (HIC3) Antacids
AHFS code 56:04.00.00
AHFS class Antacids And Adsorbents
FDB label name MAGNESIUM OXIDE 400 MG TABLET
FDB brand name Magnesium Oxide
Legend status O — Over-the-counter (OTC) drug or device
Quick answers
  • GSN (GCN sequence number): 078687
  • GCN: 45064
  • GPI-14 (Medi-Span): 48400020000310
  • HICL (First Databank): 000609
  • AHFS class code: 56:04.00.00
  • RxCUI (RxNorm): 198741
Why two NDCs? The FDA registers this code as 58657-120-12 — a 5-3-2 layout, and that's what's printed on the package and shown on DailyMed. For insurance claims, every NDC is standardized to a uniform 11-digit 5-4-2 format by adding a zero to the product segment → 58657-0120-12. Same drug, same package — only the format differs.
Where does this data come from?
Identifiers from the FDA openFDA NDC Directory and Structured Product Labeling; RxCUI from RxNorm (NLM); GPI from Medi-Span; GCN / HIC / AHFS / legend from First Databank.

RxNorm drug class

This medicine belongs to the Magnesium compounds class.

Drug family (ATC) Magnesium compounds, Osmotically acting laxatives, Magnesium
Where does this data come from?
Therapeutic classes from RxNorm RxClass (U.S. National Library of Medicine) — Established Pharmacologic Class (FDA), ATC drug family (WHO) and mechanism of action, matched by this product’s RxCUI.

Clinical

Label name MAGNESIUM OXIDE 400 MG TABLET Ingredient Magnesium Oxide
📗 Our plain-language guide HelloPharmacist
  • It's used to relieve acid indigestion and upset stomach. Some products, like Magnesium Oxide 400mg, are also used as a magnesium supplement. Check which use your product is labeled...
  • For antacid use, the labels say 1 tablet twice a day or as directed by your doctor. For supplement use, the directions vary by product, from 1 tablet daily to 1 to 2 tablets daily....
  • The dietary supplement tablet suggests taking it preferably with food. The other labels don't give a food instruction, so follow what's on your package or what your prescriber tell...
  • The main one is a laxative effect, meaning looser or more frequent stools. If that bothers you or you're using more than the label allows, check in with your doctor or pharmacist.
📖 Read our full Magnesium Oxide guide →

Supplement & herbal interactions

🌿 Drug–supplement interaction checker →
Where does this data come from?
Plain-language summary from MedlinePlus (U.S. National Library of Medicine); supplement & herbal interactions and nutrient depletion data from the Natural Medicines database; our full guide is HelloPharmacist editorial content.

Pricing

A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.

Price systemPer eaPer package
Retail pharmacies payNADAC · weekly $0.035 $4.15 / 120 tablets
Medicaid paysCMS SDUD · 12 mo $0.2027 $24.32 / 120 tablets
Medicare drug plans payPart D · quarterly No Part D plan price is available for this NDC in our data.
NADAC price history (per ea) — tap or hover for the price & month
Jan 2022 Aug 2022 Jan 2026 Sep 2026 $0.039 $0.031
▼ Down 5% over the last 24 months.
Where does this data come from?
NADAC (National Average Drug Acquisition Cost) is the CMS weekly pharmacy-acquisition-cost survey — what pharmacies pay. ASP (Average Sales Price) is the CMS Medicare Part B drug-payment file, published quarterly. Medicaid pays is computed by us from CMS State Drug Utilization Data (total reimbursed ÷ units, trailing 12 months) — gross of rebates and inclusive of dispensing fees, so it reflects what Medicaid paid, not an acquisition cost. Medicare drug plans pay is the median negotiated point-of-sale unit cost across plans listing this NDC in the CMS quarterly Prescription Drug Plan pricing files, before rebates. The VA pays is the federal contract price (FSS, and the statutory Big 4 ceiling where listed) from the VA National Acquisition Center pharmaceutical price file. All are free public government data; each measures a different payer, so the figures are not directly comparable.

Packaging — all sizes for this product

Package NDCDescription Marketing startMarketing endStatus
58657-0120-12 You're viewing this Main listing 120 TABLET in 1 BOTTLE 2018-07-25 — Active

Therapeutic equivalents

ProductLabelerPackNADAC/unitTEStatusPrice vs. this
Magnesium Oxide 400 mg 00603-0209-22 Endo 120 tablets $0.035 — Availability likely —
Magnesium Oxide 400 mg 24689-0132-01 APNAR 120 tablets $0.035 — Availability likely —
Magnesium Oxide 400 mgthis 58657-0120-12 Method 120 tablets $0.035 — Availability likely —
Magnesium Oxide 400 mg 69367-0298-20 Westminster 120 tablets $0.035 — Availability likely —
Magnesium Oxide 400 mg 81033-0027-01 Kesin 1000 tablets $0.035 — Availability likely —
Magnesium Oxide 400 mg 10135-0786-62 Marlex 120 tablets — — FDA listed —
Magnesium Oxide 400 mg 50090-7432-00 A-S 120 tablets — — FDA listed —
Magnesium Oxide 400 mg 54738-0973-12 Richmond 120 tablets — — Discontinued —
Magnesium Oxide 400 mg 63629-1126-01 Bryant 120 tablets — — Discontinued —
Magnesium Oxide 400 mg 63629-9420-01 Bryant 120 tablets — — FDA listed —
Magnesium Oxide 400mg 400 mg 69168-0174-06 Allegiant 120 tablets — — FDA listed —
Magnesium Oxide 400 mg 71335-1960-01 Bryant 60 tablets — — FDA listed —
Magnesium Oxide 400 mg 71610-0172-60 Aphena 90 tablets — — FDA listed —
Magnesium Oxide 400 mg 71610-0182-60 Aphena 90 tablets — — FDA listed —
Magnesium Oxide 400 mg 72162-1648-04 Bryant 120 tablets — — FDA listed —
Magnesium Oxide 241.3 mg/1000mg 84447-0001-12 Belleview 120 mg — — FDA listed —
About this product: other versions of the same ingredient, strength and form are listed above, least expensive first, with FDA equivalence ratings where available.
Where does this data come from?
Equivalents are other NDCs of the same ingredient, form and route from the openFDA NDC Directory, ranked least-expensive-first by NADAC. Therapeutic-equivalence (AB) ratings come from the FDA Orange Book; biologics use the FDA Purple Book for biosimilar & interchangeable status.

Availability & generic status

🏛️
2018
On the market since
Jul 2018
📍
2026
Currently FDA-listed
8 years listed
🔒
·
No generic listed yet
brand only
ℹ️No FDA-approved generic found

We did not find an FDA-approved generic match for this exact strength, form and route.

Where does this data come from?
Patents and exclusivity from the FDA Orange Book (small-molecule drugs), refreshed from public FDA data. Generic launch timing is an estimate, not a guarantee.

Inactive Ingredients / Excipients

Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.

🧪 Avoiding an ingredient? See Magnesium Oxide inactive ingredients by manufacturer: every current product's list side by side, so you can ask your pharmacy for the version that does not list it.

💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.

  • UNII OP1R32D61U
    Microcrystalline cellulose is a purified form of cellulose, a natural fiber from plant sources. It acts as a binder and filler in tablets and capsules, helping hold ingredients together and give the medicine its shape and size.
  • UNII M28OL1HH48
    Croscarmellose sodium is a plant-based substance derived from cellulose. It acts as a disintegrant, helping tablets and capsules break down quickly in the digestive system so the medicine can be absorbed.
  • UNII ETJ7Z6XBU4
    Silicon dioxide is a naturally occurring mineral used as a glidant and anti-caking agent. It helps powder ingredients flow smoothly and prevents clumping during manufacturing and storage.
  • UNII 4ELV7Z65AP
    Stearic acid is a fatty acid derived from plant or animal sources. It acts as a binder and lubricant in tablets and capsules, helping them hold together and flow smoothly during manufacturing.

4 inactive ingredients listed in the exact product block matched to this NDC.

The official label also statesCroscarmellose Sodium, Microcrystalline Cellulose, Silicon Dioxide, and Stearic Acid.

Label-section wording can be broader than the structured product block and may mention additional formulation ingredients.

Where does this data come from?
Data sourced from official FDA Structured Product Labeling (SPL) via DailyMed — ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.

Inactive ingredient FAQ

Are inactive ingredients the same for every manufacturer?
No. Inactive ingredients can differ by manufacturer, dosage form, strength, and package / product version.
Why might an inactive ingredient be missing?
Some SPLs do not provide a complete structured inactive-ingredient list, and older or unusual labels may only include the information in narrative text.
Can inactive ingredients matter?
Yes. They can matter for allergies, intolerances, dyes, gluten / lactose concerns, preservatives, and formulation differences — but confirm with a pharmacist or the manufacturer when it’s clinically important.

Manufacturer & labeler

LabelerMethod Pharmaceuticals, LLC
FDA applicationM001 (OTC MONOGRAPH DRUG)
Labeler code58657
First marketedJul 2018
Product typeHuman Otc Drug
Portfolio78 products on file

More NDCs from Method Pharmaceuticals, LLC labeler code 58657

The labeler markets the product; the application holder owns the FDA approval. They’re often the same company but can differ (e.g. a repackager or an authorized generic). A mailing address / phone appears here when the manufacturer includes it in the product’s FDA label (not all do).
Where does this data come from?
Labeler, application holder and registered establishment from the FDA openFDA NDC Directory and Drugs@FDA; address/contact from the product’s FDA label.

FDA label — Drug Facts FDA SPL

The complete FDA label for this product — the official Drug Facts labeling, verbatim, section by section. Jump with a chip, search within the label, or expand everything.
🎯 Indications and Usage ⏱️ Dosage and Administration ⚠️ Warnings 📦 Storage and Handling 🧪 Active Ingredient 🧪 Inactive Ingredients 🎯 Purpose 📄 Ask a Doctor Before Use If 📄 Keep Out of Reach of Children 📄 Questions or Comments 📄 Package Label / Principal Display Panel
🎯 Indications and Usage 8 words ▾

Use relieves: ■ acid indigestion ■ upset stomach

⏱️ Dosage and Administration 18 words ▾

Directions take one or two antacid tablets daily. Do not exceed two tablets unless directed by a physician.

⚠️ Warnings 53 words ▾

Warnings Ask a doctor before use if you have kidney disease you are taking a prescription drug (antacids may interact with certain prescription drugs) you are pregnant or breast feeding. Do not take more than 2 tablets in a 24 hour period. May have a laxative effect. Keep out of reach of children.

📦 Storage and Handling 28 words ▾

Other information Store at controlled room temperature 15° to 30°C (59° to 86°F). Tamper evident, do not use if imprinted safety seal under cap is broken or missing.

🧪 Active Ingredient 10 words ▾

Active ingredient Magnesium Oxide 400 mg (241.3 mg Elemental Magnesium)

🧪 Inactive Ingredients 11 words ▾

Inactive ingredients Croscarmellose Sodium, Microcrystalline Cellulose, Silicon Dioxide, and Stearic Acid.

🎯 Purpose 2 words ▾

Purpose Antacid

📄 Ask a Doctor Before Use If 46 words ▾

Ask a doctor before use if you have kidney disease you are taking a prescription drug (antacids may interact with certain prescription drugs) you are pregnant or breast feeding. Do not take more than 2 tablets in a 24 hour period. May have a laxative effect.

📄 Keep Out of Reach of Children 6 words ▾

Keep out of reach of children.

📄 Questions or Comments 20 words ▾

Questions? Call Method at 1-877-250-3427 or FDA at 1-800-FDA-1088 Manufactured for: Method Pharmaceuticals, LLC Fort Worth, Texas 76118 Rev. 04/18

📄 Package Label / Principal Display Panel 16 words ▾

Principal Display Panel NDC 58657-120-12 Magnesium Oxide 400 mg 241.3 Elemental Magnesium Antacid 120 Tablets label

Source: FDA Structured Product Labeling, mirrored from DailyMed / openFDA. Prefer the government’s original formatting? View this label on DailyMed ↗

Medicaid utilization & spend

📍 This exact package only: Medicaid data is reported per full 11-digit NDC — labeler, product and pack size — so every number here is for this package alone, not the drug overall. Other pack sizes report separately.
💊 Pharmacy benefit only: These are Medicaid outpatient pharmacy claims, billed by NDC. They exclude the medical benefit — clinic- or hospital-administered drugs billed under HCPCS J-codes — so drugs used mostly that way (e.g. Avastin, Lucentis, Keytruda) can look low or missing here. That’s expected, not an error.
📅 Q1 2025 – Q1 2026 · 5 quarters of data
ⓘ The newest quarter is usually incomplete when first published; states restate recent quarters in later CMS releases, so the latest figures typically revise upward. State coverage-policy changes can also shift quarter-to-quarter totals.
Prescriptions last 4 qtrs
34.3K
Units reimbursed last 4 qtrs
1.7M
Gross reimbursed last 4 qtrs
$349K
Avg / prescription
$10.17
Avg / unit
$0.2027
Latest quarter Q1 2026
7.4KRx
Medicaid pays / ea
$0.2027
gross reimbursed
vs
NADAC / ea
$0.0346
acquisition cost
=
Spread
+$0.1681
+486% vs cost
What Medicaid paid per ea (before rebates; includes the pharmacy’s dispensing fee) compared with NADAC — the average price pharmacies pay to buy the drug. A positive spread means Medicaid reimbursed more than the purchase price, before manufacturer rebates.
Fee-for-service vs managed care ⓘ
84% FFS 16% MCO
Fee-for-service · 28,838 Rx Managed care · 5,483 Rx
State Medicaid map
Alaska: no data reported AK Maine: 1,260 units · 90.3 per 100k residents ME Washington: no data reported WA Idaho: no data reported ID Montana: no data reported MT North Dakota: 2,848 units · 364 per 100k residents ND Minnesota: 15,618 units · 272 per 100k residents MN Wisconsin: no data reported WI Michigan: 47,435 units · 473 per 100k residents MI New York: 886,473 units · 4,530 per 100k residents NY Vermont: 164,995 units · 25,502 per 100k residents VT New Hampshire: 15,546 units · 1,109 per 100k residents NH Oregon: 2,989 units · 70.6 per 100k residents OR Nevada: 11,890 units · 372 per 100k residents NV Wyoming: no data reported WY South Dakota: no data reported SD Iowa: 1,560 units · 48.6 per 100k residents IA Illinois: 31,606 units · 252 per 100k residents IL Indiana: 750 units · 10.9 per 100k residents IN Ohio: 11,817 units · 100 per 100k residents OH Pennsylvania: 19,743 units · 152 per 100k residents PA New Jersey: 6,183 units · 66.6 per 100k residents NJ Massachusetts: 1,018 units · 14.5 per 100k residents MA California: 316,039 units · 811 per 100k residents CA Utah: no data reported UT Colorado: no data reported CO Nebraska: 29,767 units · 1,505 per 100k residents NE Missouri: no data reported MO Kentucky: 12,292 units · 272 per 100k residents KY West Virginia: 29,631 units · 1,674 per 100k residents WV Virginia: 19,236 units · 221 per 100k residents VA Maryland: no data reported MD Connecticut: 734 units · 20.3 per 100k residents CT Rhode Island: no data reported RI Arizona: 7,161 units · 96.4 per 100k residents AZ New Mexico: no data reported NM Kansas: no data reported KS Arkansas: no data reported AR Tennessee: no data reported TN North Carolina: no data reported NC South Carolina: 22,713 units · 423 per 100k residents SC Delaware: no data reported DE Oklahoma: no data reported OK Louisiana: no data reported LA Mississippi: no data reported MS Alabama: no data reported AL Georgia: 4,126 units · 37.4 per 100k residents GA D.C.: no data reported DC Hawaii: 4,252 units · 296 per 100k residents HI Texas: 54,238 units · 178 per 100k residents TX Florida: no data reported FL
Units reimbursed · per 100k residents
10.925,502
gray = no data reported ⓘ
Colors are per 100,000 residents, so big states don’t automatically dominate. Tap or hover a state for its actual totals.
Tap or hover a state
…for its Medicaid breakdown
🏆 Top states by units · per 100k residents
1 Vermont 25,502 /100k
2 New York 4,530 /100k
3 West Virginia 1,674 /100k
4 Nebraska 1,505 /100k
5 New Hampshire 1,109 /100k
6 California 811 /100k
7 Michigan 473 /100k
8 South Carolina 423 /100k
National units — by quarter
💵 About the dollar figures: “reimbursed” is what Medicaid paid pharmacies before confidential manufacturer rebates, so the program’s real net cost is lower than these numbers. Fee-for-service and managed-care claims are combined unless split above. Source: CMS State Drug Utilization Data; per-100k rates use 2023 Census population estimates.
← 58657-0119-01 · Method 58657-0151-01 · Method →
For educational and professional reference only — not medical advice. Pricing reflects published NADAC and CMS ASP (free public data) and may differ from your acquisition cost; always verify before billing or dispensing.