Duloxetine hydrochloride. Molecular model of the drug duloxetine hydrochloride (C18.H19.N.O.S?H.Cl). This serotonin-norepinephrine reuptake inhibitor, sold under the brand name Cymbalta, is mostly prescribed for major depressive disorder, generalized anxiety disorder, fibromyalgia and neuropathic pain. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue), oxygen (red), sulfur (yellow) and chlorine (green).