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Primidone 250 mg Tablet, 500-count — NDC 53746-0545-05 package photo

Primidone 250 mg Tablet, 500-count

by Amneal Pharmaceuticals of New York LLC · 500 TABLET in 1 BOTTLE (53746-545-05)
NDC 53746-0545-05
🏷️ FDA NDC (as labeled) 53746-545-05 billing pads the product segment with a zero
This package
Contains500-count Pack sizes3 compare ↓
Also priced by: Part D plans $0.1997/unit — full pricing hub ↓
Also comes in: 100 tablets 53746-0545-01 1000 tablets 53746-0545-10
Rx only Generic On market Non-controlled
🗂️ Data synced Jul 24, 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

🚨
Active recall for this product.
Class III · Jun 3, 2026 — Cross Contamination with Other Products: due to a potential for cross-contamination with Acemetacin API due to an issue at the API manufacturer. (Amneal Pharmaceuticals, LLC) · FDA recall D-0585-2026
Check your lot/expiration against the official notice — look up the recall number in the FDA recall database ↗
⚠️
Other active recalls for Primidone (different manufacturers) — 5 · tap to view
These affect other manufacturers’ products for the same ingredient — not necessarily the exact NDC on this page.
Class III · May 1, 2026 — Cross contamination with other products: API contaminated with trace amounts of Acemetacin API. (Amerisource Health Services LLC) · FDA recall D-0537-2026
Class III · May 1, 2026 — Cross contamination with other products: API contaminated with trace amounts of Acemetacin API. (Amerisource Health Services LLC) · FDA recall D-0536-2026
Class III · Apr 27, 2026 — Cross contamination with other products: API contaminated with trace amounts of Acemetacin API. (Golden State Medical Supply Inc.) · FDA recall D-0534-2026
Class III · Apr 27, 2026 — Cross contamination with other products: API contaminated with trace amounts of Acemetacin API. (Golden State Medical Supply Inc.) · FDA recall D-0535-2026
Class III · Apr 24, 2026 — Cross contamination with other products: API contaminated with trace amounts of Acemetacin API. (Lannett Company Inc.) · FDA recall D-0533-2026
Each entry is an official FDA enforcement report — look up any recall number in the FDA recall database ↗

🆔 Identity & classification

FDA NDC (as labeled) 53746-545-05
Product NDC 53746-545
11-digit billing NDC 53746054505
RxCUI 96304, 198150
UNII 13AFD7670Q
Application # ANDA040866
SPL Set ID 3cdc361a-5558-4341-ad40-f8bc29b4f1ce
Established class (EPC) Anti-epileptic Agent
Physiologic effect Decreased Central Nervous System Disorganized Electrical Activity
DEA schedule Non-controlled
Marketing category ANDA
Marketing status On market
FDA listing status Listed (active directory)
Marketing start 2009-12-24
Route ORAL
Dosage form TABLET
Substance PRIMIDONE
GPI-14 72600060000310
GPI class Primidone
GCN Seq No 004543
GCN 17321
HICL code 001886
Ingredient (HICL) Primidone
HIC1 code H
Therapeutic class — broad (HIC1) Nervous System (Except Autonomic)
HIC2 code H4
Therapeutic class — intermediate (HIC2) Anticonvulsants
HIC3 code H4B
Therapeutic class — specific (HIC3) Anticonvulsants
AHFS code 28:12.04.00
AHFS class Barbiturates (Anticonvulsants)
FDB label name PRIMIDONE 250 MG TABLET
FDB brand name Primidone
Legend status F — Federal legend — prescription drug or device
TE code (Orange Book) AB · RLD · RS
Why two NDCs? The FDA registers this code as 53746-545-05 — 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 → 53746-0545-05. 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 Anti-epileptic Agent class.

Pharmacologic class Anti-epileptic Agent
Drug family (ATC) Barbiturates and derivatives
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.

🏭 Manufacturer & labeler

LabelerAmneal Pharmaceuticals of New York LLC
Application holderAMNEAL PHARMACEUTICAL
FDA applicationANDA040866 (ANDA)
Labeler code53746
First marketedDec 2009
Product typeHuman Prescription Drug
Portfolio228 products on file
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.

🩺 Clinical

Label name PRIMIDONE 250 MG TABLET Ingredient Primidone
📖 What it is MedlinePlus · NLM

Primidone is used alone or with other medications to control certain types of seizures. Primidone is in a class of medications called anticonvulsants. It works by decreasing abnormal electrical activity in the brain.

Read the full MedlinePlus article ↗
📗 Our plain-language guide HelloPharmacist
  • Primidone is a seizure medicine — an anticonvulsant. It's used to control several types of epileptic seizures, including grand mal (major convulsions), psychomotor seizures, and fo...
  • Starting low and increasing gradually gives your body time to adjust. The most common early side effects — dizziness, unsteadiness, and nausea — tend to be much milder when the dos...
  • Why do I have to start at such a low dose and build up slowly?
  • Please don't stop suddenly without talking to your doctor first. Stopping an anticonvulsant abruptly can trigger a prolonged, dangerous seizure called status epilepticus — that's a...
📖 Read our full Primidone guide →
3
Nutrient depletion considerations

Primidone may be associated with lower levels of 3 nutrients — worth a chat with your pharmacist, not a cause for alarm.

🧪 Full Primidone nutrient depletion report →
An association is not a deficiency. Educational only — don't start or stop anything without professional guidance.
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.

💊 What it looks like

Color white
ShapeRound
ImprintAN;545
Size1 mm
ScoringScored — splits in 2
One label can cover several strengths, so colors may be combined — always confirm a loose pill against the dispensed prescription label or a pharmacist.
Where does this data come from?
Physical description (imprint, shape, color, scoring, coating) from this product’s FDA Structured Product Labeling (SPL), mirrored from DailyMed / openFDA.

🧪 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.

A current SPL was checked, but it does not contain a structured or narrative inactive-ingredient list for this product. This does not mean the product has no inactive ingredients.
Where does this data come from?
Source: official FDA Structured Product Labeling (SPL) via DailyMed and the openFDA label index. Structured IACT rows and label-wide narrative are kept separate; availability and product-level specificity depend on the submitted label.

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.

💲 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 eachPer package
Retail pharmacies payNADAC · weekly Not in the retail survey — common for institutional, discontinued, or low-volume packs.
Medicaid paysCMS SDUD · 12 mo No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data.
Medicare drug plans payPart D · Q2 2026 $0.1997 $99.85 / 500 tablets
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.

🔁 Therapeutic equivalents

ProductLabelerPackNADAC/unitTEStatusPrice vs. this
Primidone 250 mg 00527-1231-01 Lannett 100 tablets $0.220 AB Availability likely —
Primidone 250 mg 00591-5321-01 Actavis 100 tablets $0.220 AB Availability likely —
Primidone 250 mg 50268-0687-15 AvPAK 50 tablets $0.220 AB Availability likely —
Primidone 250 mg 68084-0203-01 American 100 tablets $0.220 AB Availability likely —
Primidone 250 mg 69584-0685-10 Oxford 100 tablets $0.220 AB Availability likely —
Primidone 250 mg 72603-0610-01 NorthStar 100 tablets $0.220 AB Availability likely —
Primidone 250 mg 72888-0046-01 Advagen 100 tablets $0.220 AB Availability likely —
Primidone 250 mg 80005-0118-11 Carnegie 100 tablets $0.220 AB Availability likely —
Primidone 250 mg 65162-0545-10 Amneal 100 tablets $0.300 AB FDA listed —
Primidone 250 mg 42291-0511-01 AvKARE 100 tablets — AB FDA listed —
Primidone 250 mg 51407-0638-01 Golden 100 tablets — AB FDA listed —
Primidone 250 mgthis 53746-0545-05 Amneal 500 tablets — AB FDA listed —
Primidone 250 mg 55111-0476-01 Dr. 100 tablets — — FDA listed —
Mysoline 250 mg 66490-0691-10 Bausch 100 tablets — AB FDA listed —
Primidone 250 mg 72789-0177-01 PD-Rx 100 tablets — AB FDA listed —
Primidone 250 mg 82804-0953-00 Proficient 100 tablets — AB FDA listed —
About this product: this is a generic version of the medicine. FDA equivalence ratings are shown when available, and other versions are listed above, least expensive first.
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

🏛️
2009
On the market since
Dec 2009
📍
2026
Currently FDA-listed
17 years listed
🔓
·
Generic on the market
this product is a generic
✅This is a generic drug

This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.

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.

💊 Medicaid utilization by pack size

Medicaid (SDUD) totals over the four most recent reported quarters for every package size of this drug — handy when a specific package (e.g. a starter/titration pack) carries little or no Medicaid volume on its own.
100 tablets53746-0545-01 4,342 Rx · $113,115
500 tablets this page53746-0545-05 No Medicaid data
1000 tablets53746-0545-10 No Medicaid data
Drug total (last 4 qtrs): 4,342 Rx · 331,080 units · $113,115 gross reimbursed
Tap a pack size to open its page. Source: CMS State Drug Utilization Data, last 4 quarters.

📊 Medicare Part D spend CMS · PART D · 2026 (Q1)

Medicare Part D (outpatient prescription) spending for Primidone — the program that covers self-administered drugs. 9 manufacturers.
⚠️ Drug-level data: CMS publishes Part D spending by drug, not by NDC — these figures combine every manufacturer, strength and package size sold under the name Primidone. That’s a different level of aggregation than the Medicaid card above, which is specific to this exact 11-digit NDC (pack size included), so the two aren’t directly comparable.
Period
Total Part D spend
$9.81M
Claims incl. refills
378.1K
Beneficiaries
228.5K
Spend / beneficiary
$42.95
Spend / claim
$25.96
Trend by period
💵 About the dollar figures: spending is what Part D plans paid before confidential manufacturer rebates, so the program’s real net cost is lower. A blank patient count means fewer than 11 people — CMS hides counts that small to protect privacy. Source: CMS Medicare Quarterly Part D Spending by Drug (data.cms.gov), updated quarterly.

🔬 Reported adverse events (FAERS)

Read carefully: FAERS reports are voluntary and unverified. Counts are not incidence, do not establish causation, are subject to reporting bias, and cannot be used to compare one drug to another. Shown for signal context only. Reports for Primidone — the ingredient across all brands.

Top reported reactions

Fall670
Fatigue645
Tremor585
Diarrhoea499
Dizziness498
Nausea471
Drug Interaction407

Age at onset

Neonate21
Infant3
Child22
Adolescent10
Adult460
Elderly827

Reporter sex

10,126 reports
Male · 40%
Female · 60%
Unknown · 0%

Serious outcomes

Hospitalization3,162
Death874
Reports over time (by year) — tap or hover for the count & year
2019 2021 2023 2026 692 311
Most recent year is provisional (FAERS lags ~3 months).
Where does this data come from?
Adverse-event reports from the FDA Adverse Event Reporting System (FAERS) via openFDA. FAERS reports are voluntary and unverified — counts are not incidence and don’t establish causation.

📦 Packaging — all sizes for this product

Package NDCDescription Per unit Per pack Marketing startStatus
53746-0545-01 100 TABLET in 1 BOTTLE (53746-545-01) $0.2197 / ea $21.97 2009-12-24 Active
53746-0545-05 You're viewing this 500 TABLET in 1 BOTTLE (53746-545-05) — — 2009-12-24 Active
53746-0545-10 1000 TABLET in 1 BOTTLE (53746-545-10) — — 2009-12-24 Active

You're viewing one of 3 pack sizes for this product.

This pack shows little to no recent Medicaid volume — the 100 tablets pack carries most fills. See all packs ↓

Pack size FAQ

What quantity is in NDC 53746-0545-05?
NDC 53746-0545-05 is a 500-count package — 500 tablet in 1 bottle.
What is the difference between NDC 53746-0545-05 and NDC 53746-0545-01?
Both are Primidone 250 mg Tablet — the drug itself is identical. NDC 53746-0545-05 is the 500-count package, while NDC 53746-0545-01 is the 100 tablets package.
What NDC number is used to bill for this package of Primidone 250 mg Tablet?
Bill NDC 53746-0545-05 — the 11-digit billing format is 53746054505. Pharmacy and medical claims use the 11-digit form; the FDA label may print a shorter form of the same code.

Prices are the latest CMS NADAC pharmacy acquisition cost per NDC; per-pack figures are per-unit × pack quantity, shown only when the pack is denominated in the same measure NADAC prices.

🧭 About this NDC listing & data coverage

Finished prescription product
What data is (and isn’t) available for this NDC — tap to expand
NDC identity (package / product / labeler codes) ✓ Available
Labeler ✓ Available
Product & package description ✓ Available
Marketing category & status ✓ Available
Active ingredient / dosage form / route ✓ Available
FDA label (SPL via DailyMed) ✓ Available
Package photos ✓ Available
Inactive ingredients (structured) — Not published for this NDC The labeler did not submit a structured excipient list, or no SPL is available.
NADAC pharmacy acquisition price (CMS) — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey.
Orange Book / therapeutic-equivalence data ✓ Available
HCPCS J-code billing crosswalk — Not published for this NDC Most self-administered / retail products have no J-code — that is normal.
Medicaid utilization (CMS SDUD) — Not published for this NDC CMS reports utilization only for NDCs with Medicaid claims above its privacy threshold.
“Not published” reflects what the public FDA / CMS / NLM sources provide for this exact package code — it is a property of the data feeds, not a judgment about the product.

Questions about this listing

Why is there no price listed?
The pricing shown on our NDC pages comes from CMS NADAC, a voluntary survey of retail community pharmacy invoices. CMS does not publish a NADAC for every NDC — packages outside the retail survey (institutional and hospital products, bulk packages, discontinued items, and many OTC items) may never receive one. A missing price reflects the survey's scope, not this product's actual cost, and does not mean the product is free or unavailable.
Is the NDC printed on the package the same as the 11-digit billing NDC?
Yes, they identify this exact package in different formats. The FDA registers it as 53746-545-05, which is what is printed on the packaging and shown on DailyMed. Insurance claims use a fixed 11-digit 5-4-2 format, so the short segment is padded with a leading zero: 53746-0545-05, written without dashes as 53746054505. The Identity section at the top of this page lists every form of this code.
What do the three segments of this NDC mean?
In 53746-0545-05, the first segment (53746) is the labeler code FDA assigned to Amneal Pharmaceuticals of New York LLC; the middle segment (0545) identifies this specific product — its ingredient, strength, and dosage form; and the last segment (05) identifies this exact package size and type. Together they name one specific package of one specific product.
Is this package still being marketed?
Yes, per the latest FDA NDC Directory data on this page: this package is listed as actively marketed, with no marketing end date reported by Amneal Pharmaceuticals of New York LLC. Listing status can change — the directory data on this page refreshes weekly.
Does this product come in other package sizes?
Yes — the FDA directory lists 2 other package presentations of this same product, including 100 tablets (53746-0545-01), 1000 tablets (53746-0545-10). Each has its own NDC and its own page — see the package list near the top of this page.
Who lists this product with the FDA?
Amneal Pharmaceuticals of New York LLC is the labeler of record for this NDC — the company under whose FDA-assigned code the package is listed. The labeler may be the manufacturer itself or a distributor marketing the product under its own code.
Do I need a prescription for this product?
This NDC is listed with FDA as a prescription product, so it is dispensed under a prescriber's order. Your pharmacist can tell you whether any over-the-counter forms of the same medication exist.
This page identifies an FDA-listed package (the NDC) and reports public regulatory and pricing data about the listing. It is reference information, not a medical recommendation — talk to your pharmacist or prescriber about your own medication.
Where does this data come from?
Listing facts (marketing category, packager status, marketing dates) from the FDA openFDA NDC Directory; label availability from DailyMed; pricing coverage from CMS NADAC; equivalence scope from the FDA Orange Book.

📄 Full prescribing information FDA SPL

The complete FDA label for this product — the official prescribing information, verbatim, section by section. Jump with a chip, search within the label, or expand everything.
🎯 Indications and Usage ⏱️ Dosage and Administration ⛔ Contraindications ⚠️ Warnings 🤒 Adverse Reactions 🧬 Clinical Pharmacology 📦 How Supplied / Storage and Handling 📋 Description 💬 Medication Guide
🎯 Indications and Usage 36 words ▾

INDICATIONS AND USAGE Primidone tablets used alone or concomitantly with other anticonvulsants, are indicated in the control of grand mal, psychomotor, and focal epileptic seizures. It may control grand mal seizures refractory to other anticonvulsant therapy.

⏱️ Dosage and Administration ~2 min read ▾

DOSAGE AND ADMINISTRATION Usual Dosage Patients 8 years of age and older who have received no previous treatment may be started on primidone tablets according to the following regimen using either 50 mg or scored 250 mg primidone tablets: Days 1 to 3: 100 to 125 mg at bedtime. Days 4 to 6: 100 to 125 mg twice a day. Days 7 to 9: 100 to 125 mg three times a day.

Day 10 to maintenance: 250 mg three times a day. For most adults and children 8 years of age and over, the usual maintenance dosage is three to four 250 mg primidone tablets in divided doses (250 mg three times a day or four times a day). If required, an increase to five or six 250 mg tablets daily may be made but daily doses should not exceed 500 mg four times a day.

Dosage should be individualized to provide maximum benefit. In some cases, serum blood level determinations of primidone may be necessary for optimal dosage adjustment. The clinically effective serum level for primidone is between 5 to 12 mcg/mL.

Patients Already Receiving Other Anticonvulsants Primidone tablets should be started at 100 to 125 mg at bedtime and gradually increased to maintenance level as the other drug is gradually decreased. This regimen should be continued until satisfactory dosage level is achieved for the combination, or the other medication is completely withdrawn. When therapy with primidone tablets alone is the objective, the transition from concomitant therapy should not be completed in less than two weeks.

Pediatric Dosage For children under 8 years of age, the following regimen may be used: Days 1 to 3: 50 mg at bedtime. Days 4 to 6: 50 mg twice a day. Days 7 to 9: 100 mg twice a day.

Day 10 to maintenance: 125 mg three times a day to 250 mg three times a day. For children under 8 years of age, the usual maintenance dosage is 125 mg to 250 mg three times daily or, 10 mg/kg/day to 25 mg/kg/day in divided doses. 36e4a4a6-figure-03

⛔ Contraindications 21 words ▾

CONTRAINDICATIONS Primidone is contraindicated in: 1) patients with porphyria and 2) patients who are hypersensitive to phenobarbital (see CLINICAL PHARMACOLOGY ).

⚠️ Warnings ~3 min read ▾

WARNINGS The abrupt withdrawal of antiepileptic medication may precipitate status epilepticus. The therapeutic efficacy of a dosage regimen takes several weeks before it can be assessed. Suicidal Behavior and Ideation Antiepileptic drugs (AEDs), including primidone, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication.

Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior. Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated.

There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide. The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.

The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5 to 100 years) in the clinical trials analyzed.

Table 1 shows absolute and relative risk by indication for all evaluated AEDs. The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications. Anyone considering prescribing primidone or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness.

Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated. Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm.

Behaviors of concern should be reported immediately to healthcare providers. Pregnancy To provide information regarding the effects of in utero exposure to primidone, physicians are advised to recommend that pregnant patients taking primidone enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll free number 1-888-233-2334, and must be done by patients themselves.

Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/. The effects of primidone in human pregnancy and nursing infants are unknown. Recent reports suggest an association between the use of…

🤒 Adverse Reactions 115 words ▾

ADVERSE REACTIONS The most frequently occurring early side effects are ataxia and vertigo. These tend to disappear with continued therapy, or with reduction of initial dosage. Occasionally, the following have been reported: nausea, anorexia, vomiting, fatigue, hyperirritability, emotional disturbances, sexual impotency, diplopia, nystagmus, drowsiness, and morbilliform skin eruptions.

Granulocytopenia, agranulocytosis, and red-cell hypoplasia and aplasia, have been reported rarely. These and, occasionally, other persistent or severe side effects may necessitate withdrawal of the drug. Megaloblastic anemia may occur as a rare idiosyncrasy to primidone and to other anticonvulsants.

The anemia responds to folic acid without necessity of discontinuing medication. To report SUSPECTED ADVERSE REACTIONS, contact Amneal Pharmaceuticals at 1-877-835-5472 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

🧬 Clinical Pharmacology 56 words ▾

CLINICAL PHARMACOLOGY Primidone raises electro- or chemoshock seizure thresholds or alters seizure patterns in experimental animals. The mechanism(s) of primidone's antiepileptic action is not known. Primidone per se has anticonvulsant activity as do its two metabolites, phenobarbital and phenylethylmalonamide (PEMA). In addition to its anticonvulsant activity, PEMA potentiates the anticonvulsant activity of phenobarbital in experimental animals.

📦 How Supplied / Storage and Handling 169 words ▾

HOW SUPPLIED Primidone Tablets USP, 50 mg are supplied as white, round, flat-faced, bevel-edged tablet, debossed “AN” above “44” on one side and cut-bisected on the other side. They are available as follows: Bottles of 100: NDC 53746-544-01 Bottles of 500: NDC 53746-544-05 Bottles of 1000: NDC 53746-544-10 Primidone Tablets USP, 250 mg are supplied as white, round, flat-faced, bevel-edged tablet, debossed “AN” bisect “545” on one side and plain on the other side. They are available as follows: Bottles of 100: NDC 53746-545-01 Bottles of 500: NDC 53746-545-05 Bottles of 1000: NDC 53746-545-10 Store at 20° to 25°C (68° to 77°F); excursions permitted between 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].

Dispense contents with a child-resistant closure (as required) and in a tight, light-resistant container as defined in the USP. KEEP THIS AND ALL MEDICATION OUT OF THE REACH OF CHILDREN. Manufactured by: Amneal Pharmaceuticals Pvt.

Ltd. Oral Solid Dosage Unit Ahmedabad 382213, INDIA Distributed by: Amneal Pharmaceuticals LLC Bridgewater, NJ 08807 Rev. 02-2022-05

📋 Description 81 words ▾

DESCRIPTION Primidone, USP is a white, crystalline, highly stable substance, M.P. 279 to 284° C. It is poorly soluble in water (60 mg per 100 mL at 37°C) and in most organic solvents.

It possesses no acidic properties, in contrast to its barbiturate analog. Chemical name: 5-ethyldihydro-5-phenyl-4,6 (1H, 5H)-pyrimidinedione. Structural formula: Primidone tablets USP, 50 mg and 250 mg, contain the following inactive ingredients: corn starch, lactose monohydrate, magnesium stearate, methyl cellulose, microcrystalline cellulose, sodium lauryl sulfate, sodium starch glycolate.

36e4a4a6-figure-01

💬 Medication Guide ~3 min read ▾

MEDICATION GUIDE Primidone ( prim’ i done ) Tablets, USP Read this Medication Guide before you start taking primidone and each time you get a refill. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or treatment.

What is the most important information I should know about primidone? Like other antiepileptic drugs, primidone may cause suicidal thoughts or actions in a very small number of people, about 1 in 500. Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you: thoughts about suicide or dying attempts to commit suicide new or worsening depression new or worsening anxiety feeling agitated or restless panic attacks trouble sleeping (insomnia) new or worsening irritability acting aggressive, being angry, or violent acting on dangerous impulses an extreme increase in activity and talking (mania) other unusual changes in behavior or mood Do not stop taking primidone without first talking to a healthcare provider.

Stopping primidone suddenly can cause serious problems. Stopping a seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus). Suicidal thoughts or actions can be caused by things other than medicines.

If you have suicidal thoughts or actions, your healthcare provider may check for other causes. How can I watch for early symptoms of suicidal thoughts and actions? Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings.

Keep all follow-up visits with your healthcare provider as scheduled. Call your healthcare provider between visits as needed, especially if you are worried about symptoms. What is primidone?

Primidone is a prescription medicine used alone or with other medicines to treat people with: generalized tonic-clonic (grand mal) seizures complex partial (psychomotor) seizures partial (focal) epileptic seizures Who should not take primidone? Do not take primidone if you: have a genetic disorder called porphyria are allergic to phenobarbital What should I tell my healthcare provider before taking primidone? Before you take primidone, tell your healthcare provider if you: have or have had depression, mood problems, or suicidal thoughts or behavior have any other medical conditions are pregnant or planning to become pregnant.

Primidone may harm your unborn baby. Tell your healthcare provider right away if you become pregnant while taking primidone. You and your healthcare provider will decide if you should take primidone while you are pregnant.

If you become pregnant while taking primidone, talk to your healthcare provider about registering with the North American Antiepileptic Drug (NAAED) Pregnancy Registry. You can enroll in this registry by calling 1-888-233-2334. The purpose of this registry is to collect information about the safety of antiepileptic drugs during pregnancy. are breastfeeding or plan to breastfeed.

Primidone can pass into breast milk. Talk to your healthcare provider about the best way to feed your baby if you take primidone. Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.

Taking primidone with certain other medicines can cause side effects or affect how well they work. Do not start or stop other medicines without talking to your healthcare provider. Know the medicines you take.

Keep a list of them and show it to your healthcare provider and pharmacist each time you get a new medicine. How should I take primidone tablets? Take primidone tablets exactly as prescribed.

Your healthcare provider will tell you how much primidone tablets to take and when to take it. Your healthcare provider may change your dose. Do not change your dose without talking to your healthcare provider.

Do not stop taking primidone tablets without first talking to your hea…

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