A 22-yeаr-оld trаnsgender mаn is brоught tо the emergency department by ambulance after his roommate reportedly found him unconscious. A suicide note and an empty pill bottle was found at the scene, but the bottle did not have a label. Upon arrival to the emergency department, patient’s temperature is 100.9 degrees F, blood pressure is 100/60 mmHg, pulse is 124/min, respirations are 8/min. On physical exam, patient’s skin is warm and dry. His pupils are dilated and reactive to light. Bowel sounds are decreased. An electrocardiograph (EKG) reveals sinus tachycardia with a QTc interval of 589 msec. There are no obvious traumatic injuries. Which of the following substances is the most likely cause of this patient’s condition?