Isamoltan (CGP 361A) is a β-adrenoceptor and serotonin 1B receptor antagonist. Isamoltane has reported activity as an anxiolytic in man. Isamoltan had been in phase III clinical trials for the treatment of anxiety. However, this research has been discontinued.

(-)-Propranolol is a small molecule β-adrenergic receptor antagonist and the active isomer of (±)-Propranolol preparations. (-)-Propranolol blocks the binding of epinephrine, norepinephrine, and other endogenous catecholamines to the β-adrenergic receptor, impeding increases in cardiac flow velocity and general stimulation of the sympathetic nervous system signaled by the association of these molecules to the β-adrenergic receptor. In addition to blockade of agonist binding, antagonism of the β-adrenergic receptor by (-)-Propranolol produces negative chronotropic and inotropic action, effectively dampening the force and rate of cardiac contraction. These negative chronotropic and inotropic effects correlate to a demonstrated suppression of adrenaline-induced cardiac arrhythmia by (-)-Propranolol. Suppression of β-adrenergic receptor activation by (-)-Propranolol has been widely exploited in counteracting situations sensitive to heightened cardiac activity including hypertension, angina pectoris, and cardiac ischemia.