Doc prescribed mirtazapine15mg to help w/ my sleeplessness. it worked great at first but now its been a little over a month and i cannot sleep. why?

Medication dose: Speak with your doctor. You may need a higher dose of mirtazepine. 15 mg is a common starter dose but many people need a higher dose over time.

Remeron (mirtazapine): As an antidepressant, Remeron (mirtazapine) can be dosed from 15mg. To 45 mg. At bedtime. Noticed u also take Celexa for depression, but not sure if that is given in daytime or evening. Discuss with your doctor possible dose adjustments to help u sleep better again.