Comprehensive medication guide to Primidone including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$30 copay for generic; typically Tier 1–2 on most Medicare Part D and private insurance plans. Prior authorization is uncommon for generic Primidone.
Estimated Cash Pricing
$12–$36 retail for a 30-day supply of generic Primidone; as low as $16.78 with GoodRx or $5.09 (50 mg) with SingleCare coupons. Brand Mysoline is significantly more expensive.
Medfinder Findability Score
82/100
On this page
Primidone (brand name Mysoline) is a first-generation barbiturate-type anticonvulsant medication first approved by the FDA on March 8, 1954. It is used to control seizures in people with epilepsy, including grand mal (tonic-clonic), psychomotor, and focal epileptic seizures. It is also widely used off-label as a first-line treatment for essential tremor — the most common movement disorder.
Generic Primidone is available in 50 mg and 250 mg tablet forms and is manufactured by multiple companies. The brand Mysoline is made by Oceanside Pharmaceuticals. Primidone is not a DEA-controlled substance.
As of 2026, Primidone is not in an official FDA shortage. Generic formulations are available from multiple manufacturers, though individual pharmacies may vary in whether they routinely stock it — making it worth verifying availability before assuming your usual pharmacy carries it.
We have a 99% success rate finding medications, even during nationwide shortages.
Need this medication?
Primidone works through a multi-component mechanism. It is metabolized in the liver to two active compounds: phenobarbital (15-25% of each dose) and PEMA (phenylethylmalonamide). All three — primidone itself, phenobarbital, and PEMA — have anticonvulsant activity.
The phenobarbital metabolite enhances GABAergic inhibition — it strengthens the brain's natural "calm down" neurotransmitter system, making neurons less likely to fire abnormally. Primidone also raises electroshock and chemoshock seizure thresholds in animal models, reducing both the likelihood and severity of seizures.
For essential tremor, primidone's anti-tremor effect appears to be independent of phenobarbital — the parent compound itself suppresses the abnormal oscillatory activity in the cerebello-thalamo-cortical circuit responsible for tremor. The exact molecular mechanism remains incompletely understood.
50 mg — tablet
Used for initial titration and maintenance dosing in essential tremor. Scored tablet.
250 mg — tablet
Standard maintenance dose tablet. Scored — can be split in half. Used for epilepsy and higher-dose essential tremor management.
Primidone is generally available in 2026 and is not on the FDA's official drug shortage list. However, many patients report difficulty finding it at their usual pharmacy. This is largely because Primidone is an older, lower-volume generic — pharmacies that see few prescriptions for it may not keep it in regular inventory, especially the 50 mg tablet strength used for titration and essential tremor dosing.
Patients should refill at least 7-10 days before running out, since running out of Primidone can be medically dangerous — abrupt discontinuation can trigger status epilepticus in epilepsy patients. Calling ahead to verify stock, asking pharmacists to special-order, or switching to a 90-day mail-order supply are all effective strategies.
If you need help finding Primidone in stock, medfinder calls pharmacies near you and texts you which ones can fill your prescription — without you waiting on hold.
Primidone is not a controlled substance, so there are no DEA-specific prescribing restrictions. Any licensed prescriber — including physicians, nurse practitioners (NPs), and physician assistants (PAs) — can prescribe Primidone in all 50 states without special DEA authorization.
In practice, Primidone is most commonly prescribed or initiated by:
Neurologists (general and epilepsy-specialized)
Epileptologists (subspecialty neurologists focused on seizure disorders)
Movement disorder specialists (for essential tremor)
Primary care physicians (for established patients and essential tremor management)
Geriatricians (for elderly patients with essential tremor)
Nurse practitioners and physician assistants (with appropriate prescribing authority)
Telehealth prescribing of Primidone is available for established patients in most states. New epilepsy diagnoses typically require in-person evaluation with EEG and imaging before antiepileptic therapy is initiated. Essential tremor may be evaluated and treated via telehealth in many states depending on the provider.
No. Primidone is not a DEA-controlled substance. Although it is a barbiturate-type drug and is metabolized to phenobarbital (which is Schedule IV), primidone itself does not carry a DEA scheduling classification.
This means Primidone can be prescribed by any licensed healthcare provider — physicians, nurse practitioners, and physician assistants — without DEA-specific prescribing restrictions. It can be transferred between pharmacies without controlled substance limitations, and no federal law mandates monthly prescription limits.
While not scheduled, Primidone should still be used only as prescribed. Do not share it with others, and do not stop taking it abruptly without medical guidance — abrupt discontinuation poses a serious risk of seizure rebound even in the absence of controlled substance scheduling.
Most common side effects occur particularly during the first few weeks of treatment and often improve as the body adjusts:
Drowsiness and sedation
Ataxia (poor coordination, unsteady gait)
Vertigo (dizziness, room-spinning sensation)
Nausea and vomiting (especially at treatment start)
Fatigue, irritability, emotional disturbances
Decreased libido / sexual impotency
Serious side effects (rare):
Granulocytopenia, agranulocytosis, blood cell disorders (rare)
Megaloblastic anemia (responds to folic acid supplementation)
Stevens-Johnson syndrome / toxic epidermal necrolysis (very rare)
Increased risk of suicidal thoughts or behavior (FDA boxed warning for all AEDs)
Know what you need? Skip the search.
Propranolol (Inderal)
Only FDA-approved medication for essential tremor. First-line alternative for ET. Contraindicated in asthma/COPD.
Levetiracetam (Keppra)
Modern antiepileptic for partial and generalized seizures. Different mechanism (SV2A binding), widely available, not controlled.
Lamotrigine (Lamictal)
Voltage-gated sodium channel blocker for seizures and bipolar disorder. Requires slow titration to avoid Stevens-Johnson syndrome.
Gabapentin (Neurontin)
Second-line option for essential tremor. Also used adjunctively for epilepsy. Generally well-tolerated. Schedule V in many states.
Prefer Primidone? We can find it.
Alcohol
majorSevere CNS and respiratory depression, potentially fatal. Avoid entirely during Primidone therapy.
Opioids / CNS depressants
majorProfound sedation, respiratory depression, coma risk. Use lowest effective doses with close monitoring if combination unavoidable.
Warfarin
moderatePrimidone reduces warfarin levels via enzyme induction. Monitor INR closely and adjust dose when starting or stopping Primidone.
Oral contraceptives
majorPrimidone significantly reduces effectiveness of hormonal birth control. Use alternative non-hormonal contraception.
Voriconazole
majorPrimidone dramatically reduces voriconazole levels, potentially causing treatment failure. Generally contraindicated.
Carbamazepine
moderateBoth drugs can reduce each other's levels, risking poor seizure control. Serum level monitoring required.
Phenytoin
moderateUnpredictable interaction — may increase or decrease phenytoin levels. Serum level monitoring required.
Corticosteroids
moderatePrimidone reduces corticosteroid effectiveness. Dose adjustment may be needed for patients on chronic steroids.
Primidone has been treating seizures and tremors for over 70 years — and despite the introduction of many newer antiepileptic drugs, it retains a meaningful clinical role in 2026. For patients with essential tremor who can't tolerate propranolol, and for epilepsy patients who have not responded adequately to first-line modern agents, Primidone remains a legitimate and effective therapeutic option.
The practical challenge for most patients is not finding a prescription — it's finding a pharmacy that reliably stocks this lower-volume generic. Proactive refill management, prescription discount cards like GoodRx or SingleCare, and mail-order pharmacy enrollment can all help ensure consistent access at an affordable price.
If you or a loved one takes Primidone and need help locating it at a pharmacy near you, medfinder can call pharmacies on your behalf and text you results — making it easier to find your medication without hours of phone calls.
Medfinder Editorial Standards
Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
Real-time availability
Medfinder is actively checking pharmacy inventory for Primidone. We don't publish a number until we have enough verified pharmacy checks to be accurate — start a search and our team confirms current availability near you, usually within 24 hours.
ChatGPT
Claude
Gemini