MYSOLINE vs SEMPREX-D

Independent side-by-side comparison.

Rated against independent regulatory sources·Last updated October 8, 2026·How we rate

Possible drug interaction. MYSOLINE and SEMPREX-D are different prescription medicines. Combining or switching between them can cause interactions — talk to a pharmacist or prescriber before making changes. This page is not medical advice.

Attribute	MYSOLINE	SEMPREX-D
Rating	74/100	New
Pharmacy pays	~$2.89 /30	—
Type	RX	RX
Active ingredient	PRIMIDONE	ACRIVASTINE AND PSEUDOEPHEDRINE HYDROCHLORIDE
Manufacturer	Valeant Pharm Intl	Endo Operations
Dosage forms	Tablet	Capsule
Drug class	Anti-Epileptic Agent	—
Boxed warning	None	None
Half-life	—	roughly 3 to 16 hours — the label does not give one number, because the elimination half-life depends on urine pH: about 3 to 6 hours when urine pH is 5 (acidic), and about 9 to 16 hours when urine pH is 8 (alkaline)
Treats	Partial Epilepsies, Tonic-Clonic Epilepsy, Tremor	—

mysoline semprex-d

Rating

74/100

New

Pharmacy pays

~$2.89 /30

—

Type

Active ingredient

PRIMIDONE

ACRIVASTINE AND PSEUDOEPHEDRINE HYDROCHLORIDE

Manufacturer

Valeant Pharm Intl

Endo Operations

Dosage forms

Tablet

Capsule

Drug class

Anti-Epileptic Agent

—

Boxed warning

None

Half-life

—

roughly 3 to 16 hours — the label does not give one number, because the elimination half-life depends on urine pH: about 3 to 6 hours when urine pH is 5 (acidic), and about 9 to 16 hours when urine pH is 8 (alkaline)

Treats

Partial Epilepsies, Tonic-Clonic Epilepsy, Tremor

—

Frequently asked questions

What is the difference between Mysoline and Semprex-D?

Mysoline contains Primidone, while Semprex-D contains Acrivastine and Pseudoephedrine Hydrochloride — they have different active ingredients.

Ratings are based on FDA regulatory (recall-safety) data. This comparison is for general reference only — not medical advice. Always consult a licensed professional before choosing or switching a medication.