What is the evidence for using suvorexant (orexin receptor antagonist) for sundowning in dementia?

Evidence for Suvorexant in Sundowning Associated with Dementia

Suvorexant has limited evidence for treating sundowning in dementia patients, and should not be considered a first-line treatment option for this specific indication. While it has demonstrated efficacy for sleep maintenance insomnia in the general adult population, there is insufficient evidence supporting its use specifically for sundowning behaviors in dementia.

Current Evidence Base

Efficacy for Sundowning

• The Cochrane review on pharmacotherapies for sleep disturbances in dementia found moderate-certainty evidence that orexin antagonists (including suvorexant) taken for four weeks by people with mild-to-moderate Alzheimer's disease:

  • Increases total nocturnal sleep time (28.2 minutes more than placebo)
  • Decreases time awake after sleep onset (15.7 minutes less than placebo)
  • May increase sleep efficiency slightly (4.26% improvement)
  • Has no clear effect on sleep latency or mean duration of sleep bouts 1

• However, these studies focused on general sleep parameters rather than specifically targeting sundowning behaviors.

Safety Considerations

• The American Academy of Sleep Medicine provides a weak recommendation for suvorexant as a treatment for sleep maintenance insomnia in adults, noting that the overall quality of evidence is low 2

• Special considerations for elderly patients with dementia:

  • Higher risk for adverse effects including daytime somnolence
  • Increased fall risk
  • Potential for cognitive and behavioral changes
  • Possible worsening of depression or suicidal thinking
  • Risk of sleep paralysis and hallucinations 3

Alternative Approaches for Sundowning

Non-Pharmacological Interventions (First-Line)

1. Light Therapy:

   • Bright light exposure (3,000-5,000 lux) for 2 hours in the morning has been found to decrease daytime napping and increase nighttime sleep in dementia patients 2
   • Helps consolidate nighttime sleep, decrease agitated behavior, and increase circadian rhythm amplitude

2. Behavioral Interventions:

   • Structured physical and social activity to provide temporal cues
   • Reduction in nighttime light and noise
   • Improvement in incontinence care
   • Multidimensional approach including increased sunlight exposure and decreased time in bed during the day 2

Alternative Pharmacological Options

1. Melatonin:

   • Studies have yielded inconsistent results for irregular sleep-wake disorder in dementia
   • May be effective in patients with known melatonin deficiency 2
   • Some evidence suggests it may decrease agitated behaviors and daytime sleepiness in elderly nursing home residents with dementia 4

2. Acetylcholinesterase Inhibitors:

   • Case report suggests improvement in sundowning in a patient with Lewy body dementia after treatment with donepezil 5

Clinical Decision Algorithm for Managing Sundowning

1. First implement non-pharmacological interventions:

   • Increase daytime light exposure (3,000-5,000 lux for 2 hours in morning)
   • Establish regular physical and social activities during daytime
   • Create optimal sleep environment (reduce noise, appropriate temperature)
   • Minimize daytime napping
   • Reduce evening stimulation

2. If non-pharmacological approaches fail, consider pharmacological options:

   • For patients with known melatonin deficiency: Trial of melatonin
   • For patients with Lewy body dementia: Consider acetylcholinesterase inhibitors
   • For patients with persistent sleep maintenance issues despite above measures: Consider suvorexant at 15mg dose for elderly patients (≥65 years)

3. When using suvorexant in dementia patients:

   • Start with 15mg dose in elderly patients
   • Monitor closely for adverse effects, particularly daytime somnolence and fall risk
   • Evaluate effectiveness specifically on sundowning behaviors
   • Discontinue if no improvement after 4 weeks or if adverse effects occur

Conclusion

While suvorexant has demonstrated efficacy for sleep maintenance insomnia in the general population, there is insufficient evidence specifically supporting its use for sundowning in dementia. Non-pharmacological approaches focusing on light therapy and behavioral interventions should be prioritized as first-line treatment. If pharmacological intervention is necessary, the choice should be guided by the specific clinical presentation, with suvorexant being considered only when other approaches have failed and sleep maintenance is a significant issue.