What development phase is Bay 4503 in?

Bay 4503 is FDA-approved (marketed).

What is the generic name of Bay 4503?

PROPIRAM is the generic (nonproprietary) name of Bay 4503.

Last reviewed 2026-04-20 · How we verify

Bay 4503 (PROPIRAM)

FDA-approved active Small molecule Quality 10/100

Propiram, marketed as Bay 4503, is an opioid receptor agonist currently on the market, with a key composition patent expiring in 2028. Its primary competitive advantage lies in its mechanism of action, which targets the Mu-type opioid receptor, similar to other established drugs like alfentanil and alvimopan. The primary risk is the potential for increased competition from off-patent generics, particularly alfentanil, which has been available since 1986.

At a glance

Generic name	PROPIRAM
Target	Mu-type opioid receptor
Modality	Small molecule
Therapeutic area	Pain
Phase	FDA-approved

Approved indications

No approved indications tracked.

Common side effects

No common side effects on file.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

Bay 4503 CI brief — competitive landscape report
Bay 4503 updates RSS · CI watch RSS