PROMETHAZINE PLAIN vs TRILAFON

Independent side-by-side comparison.

Rated against independent regulatory sources·Last updated June 7, 2026·How we rate

Possible drug interaction. PROMETHAZINE PLAIN and TRILAFON 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	PROMETHAZINE PLAIN	TRILAFON
Rating	New	New
Pharmacy pays	~$1.53 /30	~$5.68 /30
Type	RX	RX
Active ingredient	PROMETHAZINE HYDROCHLORIDE	PERPHENAZINE
Manufacturer	Pharmobedient	Schering
Dosage forms	Syrup	Tablet
Drug class	Phenothiazine	Phenothiazine
Boxed warning	Boxed warning	None
Half-life	about 9 to 16 hours	—
Treats	Anaphylaxis, Allergic Conjunctivitis, Motion Sickness	Tourette Syndrome, Huntington Disease, Nausea

promethazine plain trilafon

Rating

New

Pharmacy pays

~$1.53 /30

~$5.68 /30

Type

Active ingredient

PROMETHAZINE HYDROCHLORIDE

PERPHENAZINE

Manufacturer

Pharmobedient

Schering

Dosage forms

Syrup

Tablet

Drug class

Phenothiazine

Boxed warning

None

Half-life

about 9 to 16 hours

—

Treats

Anaphylaxis, Allergic Conjunctivitis, Motion Sickness

Tourette Syndrome, Huntington Disease, Nausea

Frequently asked questions

Which is cheaper, Promethazine Plain or Trilafon?

Promethazine Plain costs pharmacies less to acquire — about $1.53 vs $5.68 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 Promethazine Plain and Trilafon?

Promethazine Plain contains Promethazine Hydrochloride, while Trilafon contains Perphenazine — 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.