PENBRITIN-S vs UNIPEN

Independent side-by-side comparison.

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

Possible drug interaction. PENBRITIN-S and UNIPEN 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	PENBRITIN-S	UNIPEN
Rating	New	New
Pharmacy pays	~$13.42 /30	—
Type	RX	RX
Active ingredient	AMPICILLIN SODIUM	NAFCILLIN SODIUM
Manufacturer	Wyeth Ayerst	Wyeth Ayerst
Dosage forms	Injectable	Injectable
Drug class	Penicillin-Class Antibacterial	Penicillin-Class Antibacterial
Boxed warning	None	None
Treats	Actinomycosis, Human Bites, Bacillary Dysentery	Cellulitis, Bacterial Endocarditis, Osteomyelitis

penbritin-s unipen

Rating

New

Pharmacy pays

~$13.42 /30

—

Type

Active ingredient

AMPICILLIN SODIUM

NAFCILLIN SODIUM

Manufacturer

Wyeth Ayerst

Dosage forms

Injectable

Drug class

Penicillin-Class Antibacterial

Boxed warning

None

Treats

Actinomycosis, Human Bites, Bacillary Dysentery

Cellulitis, Bacterial Endocarditis, Osteomyelitis

Frequently asked questions

What is the difference between Penbritin-S and Unipen?

Penbritin-S contains Ampicillin Sodium, while Unipen contains Nafcillin Sodium — 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.