The present invention is directed to substituted propylamine derivatives of formula I: or a pharmaceutically acceptable salt thereof, compositions containing these derivatives, and methods of their use for the prevention and treatment of conditions ameliorated by monoamine reuptake including, inter alia, vasomotor symptoms (VMS), sexual dysfunction, gastrointestinal and genitourinary disorders, chronic fatigue syndrome, fibromylagia syndrome, nervous system disorders, and combinations thereof, particularly those conditions selected from the group consisting of major depressive disorder, vasomotor symptoms, stress and urge urinary incontinence, fibromyalgia, pain, diabetic neuropathy, and combinations thereof.