FLAGYL ER vs PROTOSTAT

Independent side-by-side comparison.

Rated against independent regulatory sources·Last updated August 20, 2026·How we rate

Attribute	FLAGYL ER	PROTOSTAT
Rating	64/100	New
Pharmacy pays	$0.10 /g	$0.10 /g
Type	RX	RX
Active ingredient	METRONIDAZOLE	METRONIDAZOLE
Manufacturer	Pfizer	Ortho Mcneil Pharm
Dosage forms	Tablet, extended release	Tablet
Drug class	Nitroimidazole Antimicrobial	Nitroimidazole Antimicrobial
Boxed warning	None	None
Half-life	about 8 hours	about 8 hours
Treats	Abscess, Amebiasis, Bacteroides Infections	Abscess, Amebiasis, Bacteroides Infections

flagyl er protostat

Rating

64/100

New

Pharmacy pays

$0.10 /g

Type

Active ingredient

METRONIDAZOLE

Manufacturer

Pfizer

Ortho Mcneil Pharm

Dosage forms

Tablet, extended release

Tablet

Drug class

Nitroimidazole Antimicrobial

Boxed warning

None

Half-life

about 8 hours

Treats

Abscess, Amebiasis, Bacteroides Infections

Frequently asked questions

Which is cheaper, Flagyl ER or Protostat?

Pharmacies pay about the same to acquire either one — roughly $0.10 per gm, per the CMS NADAC survey. That is not what you will be charged: your price is set by your insurer and the pharmacy, not by what the drug cost them.

What is the difference between Flagyl ER and Protostat?

Both Flagyl ER and Protostat share the active ingredient Metronidazole.

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.