Corynanthine is one of the two diastereomers of yohimbine (the other is alpha-yohimbine). Corynanthine is an antagonist of the alpha-1, alpha-2A and alpha-2C adrenergic receptors showing greater selectivity for the alpha-1 adrenergic receptor. Corynanthine was tested as the active ingredient of eye drops in a small clinical trial for Ocular hypertension where formulations of 2% and 5% demonstrated relief of symptoms.