I've had really bad insomina where I sleep for only an hour and then wake up. I'm able to get back asleep but I always wake up after an hour. My psychiatrist prescribed mirtazapine 7.5 mg/15mg for it but only as needed. Does this sound right? My pharmacist says you have to take it every night but when I asked my psychiatrist she said because it's such a low dose I don't have to. Has anyone else heard of mirtazapine being prescribed only as needed?