What is "pronethalol"

n. An early non-selective beta blocker clinical candidate, never used clinically due to carcinogenicity in mice.

Pronethalol (Alderlin, Nethalide) was an early non-selective beta blocker clinical candidate. It was never used clinically due to carcinogenicity in mice, which was thought to result from formation of a carcinogenic naphthalene epoxide metabolite.