Mirtazapine and Melatonin Combination Therapy for Insomnia

Recommendation and Rationale

The American Academy of Sleep Medicine recommends that sedating antidepressants like mirtazapine are considered a third-line option for insomnia treatment after short-intermediate acting benzodiazepine receptor agonists and ramelteon, due to limited evidence supporting its efficacy and potential for additive sedative effects 1, 2
Melatonin binds to M1 and M2 receptors, suppressing REM sleep motor tone and normalizing circadian features of sleep, but is not recommended as a first-line treatment for chronic insomnia due to relative lack of efficacy and safety data 1, 3, 2

The American Academy of Sleep Medicine guidelines suggest that first-line treatment for insomnia should be cognitive behavioral therapy for insomnia (CBT-I) before considering pharmacological options, with sedating antidepressants like mirtazapine as a third-line option 1, 2
For pharmacological management of insomnia, the recommended sequence is: short-intermediate acting benzodiazepine receptor agonists or ramelteon, followed by alternate agents, and then sedating antidepressants like mirtazapine 1, 2

The American Geriatrics Society lists mirtazapine as a potentially inappropriate medication in older adults, recommending lower doses (7.5mg) to minimize sedation 3
Immediate-release melatonin is typically started at 3mg at bedtime for sleep disorders, and when combining with mirtazapine, consider starting with lower doses of each to minimize the risk of excessive sedation 3

The National Comprehensive Cancer Network (NCCN) guidelines suggest that mirtazapine may be especially effective in patients with depression and anorexia who also have sleep disturbances 4
For refractory insomnia, mirtazapine is included among sedating antidepressants that can be considered as a pharmacological management option 4

Lower doses (7.5-15mg) are typically more sedating due to greater histaminergic effects 5

First-line treatments for insomnia should include cognitive behavioral therapy (CBT) before considering pharmacological options 6
For refractory insomnia, other pharmacological options include short-acting benzodiazepines (lorazepam) 4
For refractory insomnia, other pharmacological options include non-benzodiazepine hypnotics (zolpidem, zaleplon) 5
For refractory insomnia, other pharmacological options include other sedating antidepressants (trazodone) 5

In cancer patients with sleep disturbances, mirtazapine has been shown to increase total nighttime sleep 7
In children with autism spectrum disorders and sleep problems, mirtazapine has shown improvement in sleep disorders 8

The American Medical Association does not recommend mirtazapine for insomnia due to a relative lack of evidence or concerns about side effects 6