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Primidone 250 mg Tablet, 32,004-count — NDC 00591-5321-77 package photo
Label image from the product's FDA listing (DailyMed) — may show a different pack size or an older label revision.

Primidone 250 mg Tablet, 32,004-count — NDC 0591-5321-77 (Billing 00591-5321-77)

by Actavis Pharma, Inc. · 32004 TABLET in 1 CONTAINER

This is a package of 32,004 tablets of Primidone 250 mg Tablet from Actavis Pharma, Inc., marketed since Jun 2010 and currently FDA-listed.

NDC 00591-5321-77
🏷️ FDA NDC (as labeled) 0591-5321-77 billing pads the labeler segment with a zero
This package
Contains32,004-count Pack sizes4 compare ↓
Product page 00591-5321-01 Also comes in: 100 tablets 0591-5321-01 1000 tablets 0591-5321-10 27000 tablets 0591-5321-00
Rx only Generic On market Non-controlled ⇄ Compare with another NDC
🗂️ FDA directory synced Oct 1, 2026 · this listing last changed Sep 3, 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

⚠️
Other active recalls for Primidone (different manufacturers) — 6 · tap to view
These affect other manufacturers’ products for the same ingredient — not necessarily the exact NDC on this page.
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
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

Regulatory identifiers FDA, NLM and CMS codes for this package

FDA NDC (as labeled) 0591-5321-77
Product NDC 0591-5321
11-digit billing NDC 00591532177
RxCUI 96304
UNII 13AFD7670Q
UPC 0305915321012
Application # ANDA083551
SPL Set ID ae0fa704-818e-4423-8e3a-6cc3390cdd7d
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 2010-06-19
Marketing end 2027-07-31
Route ORAL
Dosage form TABLET
Substance PRIMIDONE
TE code (Orange Book) AB · RLD · RS

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

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
Quick answers
  • GSN (GCN sequence number): 004543
  • GCN: 17321
  • HICL (First Databank): 001886
  • AHFS class code: 28:12.04.00
  • RxCUI (RxNorm): 96304
Why two NDCs? The FDA registers this code as 0591-5321-77 — a 4-4-2 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 labeler segment → 00591-5321-77. 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.

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 helps control certain epileptic seizures: grand mal, psychomotor, and focal seizures. You can take it alone or with other seizure medicines. It may also help grand mal se...
  • You swallow the tablets by mouth. Your doctor will usually start you on a small bedtime dose and increase it over about 10 days. After that you take it in divided doses through the...
  • Early on, many people feel dizzy or unsteady. This often fades with time or a lower starting dose. Nausea, tiredness, drowsiness, double vision, and irritability can also happen. T...
  • No. Stopping suddenly can trigger status epilepticus, a prolonged and dangerous seizure. If you want to stop or change your dose, talk to your doctor first so it can be done safely...
📖 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.

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 · quarterly No Part D plan price is available for this NDC in our data.
ℹ️
No price is published for this exact package yet. CMS surveys NADAC per package size, so a different pack of the same drug often has one.
Try another pack size: 100 tablets 1000 tablets 27000 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.

Packaging — all sizes for this product

Package NDCDescription Per unit Per pack Marketing startMarketing endStatus
00591-5321-01 0591-5321-01 Main listing 100 TABLET in 1 BOTTLE, PLASTIC $0.2276 / ea $22.76 2010-06-19 Jul 31, 2027 Active
00591-5321-10 0591-5321-10 1000 TABLET in 1 BOTTLE, PLASTIC — — 2010-06-19 — Discontinued by firm
00591-5321-00 0591-5321-00 27000 TABLET in 1 BAG — — — — Active
00591-5321-77 You're viewing this 32004 TABLET in 1 CONTAINER — — — — Active

You're viewing the largest of 4 pack sizes for this product.

Pack size FAQ

What quantity is in this package?
This is a 32,004-count package — 32004 tablet in 1 container.
How does this package differ from NDC 00591-5321-01?
Both are Primidone 250 mg Tablet — the drug itself is identical. This page's package is the 32,004-count one, while NDC 00591-5321-01 is the 100 tablets package.
What NDC number is used to bill for this package of Primidone 250 mg Tablet?
Use the 11-digit billing form listed in the identifiers section of this page. 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.

Therapeutic equivalents

ProductLabelerPackNADAC/unitTEStatusPrice vs. this
Primidone 250 mg 00527-1231-01 Lannett 100 tablets $0.228 AB Availability likely —
Primidone 250 mg 50268-0687-15 AvPAK 50 tablets $0.228 AB Availability likely —
Primidone 250 mg 53746-0545-01 Amneal 100 tablets $0.228 AB Availability likely —
Primidone 250 mg 68084-0203-01 American 100 tablets $0.228 AB Availability likely —
Primidone 250 mg 69584-0685-10 Oxford 100 tablets $0.228 AB Availability likely —
Primidone 250 mg 72603-0610-01 NorthStar 100 tablets $0.228 AB Availability likely —
Primidone 250 mg 72888-0046-01 Advagen 100 tablets $0.228 AB Availability likely —
Primidone 250 mg 80005-0118-11 Carnegie 100 tablets $0.228 AB Availability likely —
Primidone 250 mg 65162-0545-10 Amneal 100 tablets $0.300 AB FDA listed —
Primidone 250 mgthis 00591-5321-77 Actavis 32004 tablets — 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 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

🏛️
2010
On the market since
Jun 2010
📍
2026
Currently FDA-listed
16 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.

What it looks like

Color white
ShapeRound
ImprintDAN;DAN;5321
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.

💡 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 F05Q2T2JA0
    Docusate sodium is a stool softener compound that helps medicines dissolve and move through the digestive tract. It acts as a surfactant, reducing surface tension in the intestines, and also serves as a wetting agent in tablet formulations.
  • UNII 70097M6I30
    Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
  • 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 OJ245FE5EU
    Sodium benzoate is a salt derived from benzoic acid, a preservative. It's added to medicines to prevent growth of bacteria, fungi, and other microorganisms that could spoil the product.
  • UNII 5856J3G2A2
    A starch-based powder made from potatoes and processed with sodium. It acts as a disintegrant, helping the tablet or capsule break apart quickly in the stomach so the medicine can be absorbed.
  • 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.

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

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

LabelerActavis Pharma, Inc.
Application holderWATSON LABORATORIES INC
FDA applicationANDA083551 (ANDA)
Labeler code00591
First marketedJun 2010
Product typeHuman Prescription Drug
Portfolio324 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.

Full prescribing information FDA SPL

The complete FDA label for this product — the official prescribing information, verbatim, section by section. Very long sections are excerpted here and marked; the full text is on DailyMed (linked in the sources below). 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 💬 Information for Patients 💬 Medication Guide ⚠️ Precautions 🍼 Nursing Mothers 📄 Package Label / Principal Display Panel
🎯 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 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. INITIAL: ADULTS AND CHILDREN OVER 8 KEY:• = 50 mg tablet; ● = 250 mg tablet DAY 1 2 3 4 5 6 AM •• •• •• NOON PM •• •• •• •• •• •• DAY 7 8 9 10 11 12 AM •• •• •• ● Adjust to Maintenance NOON •• •• •• ● PM •• •• •• ● Patients Already Receiving Other Anticonvulsants Primidone 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 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 to 250 mg three times daily or, 10 to 25 mg/kg/day in divided doses.

⛔ 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. Table 1: Risk by indication for antiepileptic drugs in the pooled analysis Indication Placebo Patients with Events Per 1000 Patients Drug Patients with Events Per 1000 Patients Relative Risk: Incidence of Events in Drug Patients/ Incidence in Placebo Patients Risk Difference: Additional Drug Patients with Events Per 1000 Patients Epilepsy 1.0 3.4 3.5

2.4Psychiatric 5.7 8.5 1.5

2.9Other 1.0 1.8 1.9

0.9Total 2.4 4.3 1.8

1.9The 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 tak… [Excerpted — this section continues on DailyMed.]

🤒 Adverse Reactions 114 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 Teva at 1-888-838-2872 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 71 words ▾

HOW SUPPLIED Primidone tablets USP, 250 mg are scored, round, white tablets imprinted DAN DAN and 5321 supplied in bottles of 100 (NDC 0591-5321-01). Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Dispense in a tight, light-resistant container with a child-resistant closure.

Manufactured In India By: Watson Pharma Private Limited Verna, Salcette Goa 403 722 INDIA Manufactured For: Teva Pharmaceuticals Parsippany, NJ 07054 Rev. B 2/2026

📋 Description 86 words ▾

DESCRIPTION Chemical name: 5-ethyldihydro-5-phenyl-4,6 (1H, 5H)-pyrimidinedione. Structural formula: Primidone, USP is a white, crystalline, highly stable substance, M.P. 279-284°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. Each tablet, for oral administration, contains 250 mg primidone.

In addition, each tablet contains the following inactive ingredients: colloidal silicon dioxide, docusate sodium, magnesium stearate, microcrystalline cellulose, sodium benzoate, sodium starch glycolate and stearic acid. Primidone structural formula

💬 Information for Patients 132 words ▾

Information for Patients Suicidal Thoughts and Behavior Patients, their caregivers, and families should be counseled that AEDs, including primidone, may increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of 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 Patients should be encouraged to enroll in the NAAED Pregnancy Registry if they become pregnant.

This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll free number 1-888-233-2334 (see WARNINGS, Pregnancy ). Please refer to the Primidone Medication Guide provided with the product for more information.

💬 Medication Guide ~3 min read ▾

MEDICATION GUIDE Primidone (prim' i done) Tablets, USP Read this Medication Guide before you start taking primidone tablets 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 tablets? 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 primidone tablets without first talking to a healthcare provider.

Stopping primidone tablets 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 are primidone tablets?

Primidone tablets are 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 tablets? Do not take primidone tablets if you: have a genetic disorder called porphyria are allergic to phenobarbital What should I tell my healthcare provider before taking primidone tablets?

Before you take primidone tablets, 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 tablets.

You and your healthcare provider will decide if you should take primidone tablets while you are pregnant. If you become pregnant while taking primidone tablets, 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 tablets.

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Taking primidone tablets 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 many primidone tablets to take and when to take it. Your healthcare provider may change your dose.

Do not change your dose with… [Excerpted — this section continues on DailyMed.]

⚠️ Precautions ~1 min read ▾

PRECAUTIONS The total daily dosage should not exceed 2 g. Since primidone therapy generally extends over prolonged periods, a complete blood count and a sequential multiple analysis-12 (SMA-12) test should be made every six months. Nursing Mothers There is evidence in mothers treated with primidone that the drug appears in breast milk in substantial quantities.

Since tests for the presence of primidone in biological fluids are too complex to be carried out in the average clinical laboratory, it is suggested that the presence of undue somnolence and drowsiness in nursing newborns of primidone-treated mothers be taken as an indication that nursing should be discontinued. Information for Patients Suicidal Thoughts and Behavior Patients, their caregivers, and families should be counseled that AEDs, including primidone, may increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of 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 Patients should be encouraged to enroll in the NAAED Pregnancy Registry if they become pregnant. This registry is collecting information about the safety of antiepileptic drugs during pregnancy.

To enroll, patients can call the toll free number 1-888-233-2334 (see WARNINGS, Pregnancy ). Please refer to the Primidone Medication Guide provided with the product for more information.

🍼 Nursing Mothers 69 words ▾

Nursing Mothers There is evidence in mothers treated with primidone that the drug appears in breast milk in substantial quantities. Since tests for the presence of primidone in biological fluids are too complex to be carried out in the average clinical laboratory, it is suggested that the presence of undue somnolence and drowsiness in nursing newborns of primidone-treated mothers be taken as an indication that nursing should be discontinued.

📄 Package Label / Principal Display Panel 24 words ▾

PRINCIPAL DISPLAY PANEL NDC 0591-5321-01 Primidone Tablets, USP 250 mg PHARMACIST: Dispense the accompanying Medication Guide to each patient Rx Only 100 Tablets 1

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

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.

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) ✓ 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 form printed on the packaging and shown on DailyMed is the one the FDA registered. Insurance claims use a fixed 11-digit 5-4-2 format, so the short segment is padded with a leading zero and the dashes are dropped. The Identity section at the top of this page lists each form of this code.
Is this package still being marketed?
Yes, per the latest FDA NDC Directory data on this page it is currently marketed — but Actavis Pharma, Inc. has reported a marketing end date of 2027-07-31, after which this package is expected to stop being marketed. The directory data on this page refreshes weekly.
Does this product come in other package sizes?
Yes — the FDA directory lists 3 other package presentations of this same product, including 100 tablets (00591-5321-01), 1000 tablets (00591-5321-10), 27000 tablets (00591-5321-00). 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?
Actavis Pharma, Inc. 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.
← 00591-5319-01 · Actavis 00591-5325-01 · Actavis →
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.