Hi, thanks for the query, I would like to know whether this was just one off instance of difficulty falling asleep or has there been a pattern of difficulty falling asleep even prior to starting duromine (Phenteramine)? As duromine is a stimulant, it may cause difficulty falling asleep; but since its only 2nd day of treatment, I think you should change the timing of taking medication to 8-9am morning & observe if your sleep difficulty improves or persists. Also, have you got any snoring problems? Request your doctor to have an assessment to rule out a condition named obstructive sleep apnoea which occurs in obese people & is a reason of poor sleep. Do get back to me if needed. Good Luck