Question 1

What is primidone?

Accepted Answer

Chemical name: 5-ethyldihydro-5-phenyl-4,6 (1H, 5H)-pyrimidinedione. Structural formula: MYSOLINE (primidone) 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. MYSOLINE 50 mg and 250 mg tablets contain the following inactive ingredients: lactose monohydrate, NF; magnesium stearate, NF; methylcellulose, USP; microcrystalline cellulose, NF; purified water, USP; sodium lauryl sulfate, NF; sodium starch glycolate, NF; and talc, USP. MYSOLINE 250 mg tablets also contain ferric oxide yellow, NF. _______________________________________________________________________________ ACTIONS MYSOLINE 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. Chemical Structure

Question 2

What kind of drug is primidone?

Accepted Answer

The FDA classifies primidone as an anti-epileptic agent. Anti-epileptic (anticonvulsant) drugs calm the abnormal, excessive electrical activity that triggers seizures. They do this by stabilizing overactive sodium or calcium channels in nerve cells, boosting the brain's natural calming chemical GABA, or dampening excitatory signals, which makes nerves less likely to fire uncontrollably. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.

Question 3

Can you take primidone with other medicines?

Accepted Answer

It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run primidone against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.

Question 4

What brand names is primidone sold under?

Accepted Answer

We track 2 primidone-containing products in the U.S.: Mysoline and Primidone. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.

Question 5

What forms does primidone come in?

Accepted Answer

Across the brands we track, primidone is currently marketed as tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Question 6

Is there a generic primidone?

Accepted Answer

Yes. Our catalog lists 1 generic primidone product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.

Question 7

Has primidone been recalled?

Accepted Answer

The FDA's Enforcement database lists at least 5 recall records whose product description mentions primidone. The most recent: Primidone Tablets (Jun 3, 2026). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.

#	Drug	Rating	Type	Form	Generic?	Typical price
1	Mysoline	72/100	Prescription	Tablet	Generic	$3	View →
2	Primidone	70/100	Prescription	Tablet	Generic

Primidone: uses, dosing, side effects & brands

Key facts

How primidone is dosed

Primidone side effects

Every primidone product we track (2)

What primidone pills look like

Primidone recalls

Frequently asked questions

Who shouldn’t take primidone

Imprint	Strength	Colour	Shape	Maker
AN;44	50 mg	white	round	—
AN;44	50 mg	white	round	—
AN;545	250 mg	white	round	—
AN;44	50 mg	white	round	—
AN;545	250 mg	white	round	—
DAN;DAN;5321	250 mg