Can mirtazapine be used to treat sleep disorders?

Mirtazapine for Sleep Disorders

Mirtazapine is effective for treating sleep disorders, particularly in patients with chronic insomnia, and can be recommended as a pharmacological option when non-pharmacological approaches have failed. 1

Efficacy for Sleep Disorders

• Mirtazapine significantly improves sleep parameters including total sleep time, sleep efficiency, and sleep quality in patients with insomnia 2
• In a recent randomized double-blind placebo-controlled trial specifically studying older adults with chronic insomnia, mirtazapine 7.5mg was superior to placebo in reducing insomnia severity as measured by the Insomnia Severity Index 1
• Mirtazapine decreases sleep latency (time to fall asleep) and increases slow-wave sleep percentages, which persists after 5 weeks of treatment 2

Clinical Applications

• Mirtazapine is particularly effective for patients with comorbid depression and sleep disturbances 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

Dosing Considerations

• Lower doses (7.5-15mg) are typically more sedating due to greater histaminergic effects 4
• Administration should be at bedtime to maximize sleep benefits and minimize daytime impairment 5
• Fixed dosing regimens (30mg at bedtime) have shown greater effects on sleep compared to ascending dose regimens 6

Side Effects and Precautions

• Common side effects include:

  • Somnolence (reported in 54% of patients vs 18% for placebo) 5
  • Increased appetite and weight gain (appetite increase reported in 17% of patients vs 2% for placebo) 5
  • Dizziness (7% of patients vs 3% for placebo) 5

• Important precautions:

  • Discontinuation should be gradual to avoid withdrawal symptoms 5
  • May cause vivid dreams or nightmares in some patients 7
  • Caution in elderly patients due to increased risk of side effects 5

Comparative Efficacy

• Mirtazapine's sleep-promoting effects are significantly greater than placebo and similar to tricyclic antidepressants 3
• When compared to other antidepressants, mirtazapine showed similar sleep benefits to SSRIs and SNRIs, with the exception of being superior to venlafaxine for sleep parameters 3

Alternative Options for Insomnia

• First-line treatments for insomnia should include cognitive behavioral therapy (CBT) before considering pharmacological options 4
• For refractory insomnia, other pharmacological options include:
  • Short-acting benzodiazepines (lorazepam) 4
  • Non-benzodiazepine hypnotics (zolpidem, zaleplon) 4
  • Other sedating antidepressants (trazodone) 4

Special Populations

• In cancer patients with sleep disturbances, mirtazapine has been shown to increase total nighttime sleep 4
• In children with autism spectrum disorders and sleep problems, mirtazapine has shown improvement in sleep disorders 4
• In elderly patients, mirtazapine at 7.5mg has demonstrated efficacy for chronic insomnia, though with higher rates of adverse events compared to placebo 1

Limitations and Caveats

• The American Medical Association does not recommend mirtazapine for insomnia due to a relative lack of evidence or concerns about side effects 4
• Mirtazapine may cause next-day impairment and patients should be cautioned about engaging in activities requiring alertness until they have assessed the drug's effect on their psychomotor performance 5
• While effective for sleep, the sedative effects must be balanced against potential side effects including weight gain and daytime sedation 3