penbutolol

Penbutolol is a **non-selective beta-adrenergic receptor antagonist (beta blocker)** used primarily to treat mild to moderate hypertension (high blood pressure), either alone or in combination with other antihypertensive agents[1][3][8]. It binds to **both beta-1 and beta-2 adrenergic receptors** and possesses **intrinsic sympathomimetic activity** as a partial agonist at these sites[1][3][7]. This partial agonism helps reduce the risk of excessive bradycardia compared to pure antagonists[1][3][7]. Penbutolol also acts as an **antagonist at serotonin 5-HT1A and 5-HT1B receptors**[1][3]. By blocking beta-1 receptors in the heart and kidneys, penbutolol reduces heart rate, cardiac output, and renin secretion, thus lowering arterial blood pressure[1][3][7]. It was approved by the FDA in 1987 for hypertension, but was withdrawn from the US market by 2015, though not for safety reasons[1].

Brand names

LevatolLevatololLobetaPaginolHostablocBetapressin

Other names

penbutololum(2S)-1-(tert-butylamino)-3-(2-cyclopentylphenoxy)propan-2-ol