MYSOLINE vs PHERAZINE DM

Independent side-by-side comparison.

Rated against independent regulatory sources·Last updated October 9, 2026·How we rate

Possible drug interaction. MYSOLINE and PHERAZINE DM 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	PHERAZINE DM
Rating	74/100	New
Pharmacy pays	~$2.89 /30	~$2.55 /30
Type	RX	RX
Active ingredient	PRIMIDONE	DEXTROMETHORPHAN HYDROBROMIDE AND PROMETHAZINE HYDROCHLORIDE
Manufacturer	Valeant Pharm Intl	Halsey
Dosage forms	Tablet	Syrup
Drug class	Anti-Epileptic Agent	—
Boxed warning	None	None
Half-life	—	about 9 to 16 hours
Treats	Partial Epilepsies, Tonic-Clonic Epilepsy, Tremor	—

mysoline pherazine dm

Rating

74/100

New

Pharmacy pays

~$2.89 /30

~$2.55 /30

Type

Active ingredient

PRIMIDONE

DEXTROMETHORPHAN HYDROBROMIDE AND PROMETHAZINE HYDROCHLORIDE

Manufacturer

Valeant Pharm Intl

Halsey

Dosage forms

Tablet

Syrup

Drug class

Anti-Epileptic Agent

—

Boxed warning

None

Half-life

—

about 9 to 16 hours

Treats

Partial Epilepsies, Tonic-Clonic Epilepsy, Tremor

—

Frequently asked questions

Which is cheaper, Mysoline or Pherazine Dm?

Pherazine Dm costs pharmacies less to acquire — about $2.55 vs $2.89 for a 30-count supply, per the CMS NADAC survey. That gap is in the pharmacy's cost of goods, not necessarily in what you pay: your price is set afterwards by your insurer and the pharmacy.

What is the difference between Mysoline and Pherazine Dm?

Mysoline contains Primidone, while Pherazine Dm contains Dextromethorphan Hydrobromide and Promethazine 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.