Role of Mirtazapine in Ameliorating Sleep Disordered Breathing

The purpose of this study is to look at the effect of using Mirtazapine to target a specific pathway in the body, that relies on a natural chemical the body produces called 'serotonin', in patients with spinal cord injury (SCI) and non-injured persons during sleep. During this part of the study participants will be asked to take Mirtazapine (15mg per day) and a placebo in a random fashion, each for a one week period (drug period) of time followed by one week without drugs (washout period). The drugs will not be taken all at the same time, but each will be taken separately for one weeks followed by a night study to look at the effect the Mirtazapine/placebo pill has on the way the body responds during sleep.

Randomized placebo controlled cross-over study. Each subject will be studied on two separate occasions: (1) Mirtazapine vs. placebo for one week; the participants will be blinded to whether they are taking Mirtazapine or placebo. After the one week treatment a sleep study will be repeated. Mirtazapine will be given at 15 mg dose before bed-time. (2) Cross over medication for one week will be followed by a second sleep study.

Randomized placebo-controlled cross-over study. Each subject was studied on two separate occasions: (1) Mirtazapine vs. placebo for one week; After the one-week treatment a physiological sleep study was performed to determine the CO2 reserve (Delta-PETCO2-AT) and hypocapnic apneic threshold. (2) Cross over medication for one week was followed by a second physiological sleep study to determine the CO2 reserve (Delta-PETCO2-AT) and hypocapnic apneic threshold.

AHI is an index that measures the severity of sleep apnea and is calculated by dividing the total number of apneas and hypopneas by the number of hours of sleep. Randomized placebo-controlled cross-over study. Each subject was studied on two separate occasions: (1) Mirtazapine vs. placebo for one week; After the one-week treatment a polysomnogram (PSG) study was performed to determine the AHI. (2) Cross over medication for one week was followed by a second PSG to determine the AHI.

Inclusion Criteria: Adults with SCI (>6months after spinal cord injury) at the T6 level/above Non-injured adults Exclusion Criteria: Pregnant and lactating females Heart failure, vascular disease, or stroke Advanced chronic obstructive pulmonary disease (COPD), liver disease, and chronic kidney disease BMI >38 kg/m2 Mechanical ventilation dependence