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n_insomnia

insomnia

Introduction:

  • see physiology of sleep for details on control of sleep, sleep requirements, etc.
  • consequences of acute sleep deprivation include:
    • impaired passive vigilance
    • impaired reaction time
    • impaired hand-eye coordination - ever tried playing a musical instrument or even golf after little sleep?
    • impaired clerical accuracy
    • impaired memory
    • impaired reasoning
    • increased sleepiness and micro-sleep events (eg. when driving a car)
    • increased risk of car accident and other accidents
  • consequences of slow wave (delta wave) sleep deprivation include:
    • impaired cognitive performance
    • impaired immunity and ability to recuperate
  • consequences of REM sleep deprivation include:
    • moodiness and risk of both depression and hypomanic states
    • hypersensitivity to stimuli (and perhaps lowering of the migrain threshold)
    • inability to consolidate complex learning
  • consequences of long term sleep deprivation include:
    • decreased longevity in animal models
    • depression
    • burnout
    • divorce
    • substance abuse
    • chronic hypertension
    • metabolic syndrome, obesity and diabetes mellitus
    • increased cardiovascular mortality equivalent to more than 1 packet/day of cigarettes
    • infertility
    • injury risk
  • sleep debt:
    • sleep latency can be measured
    • very poor correlation between self-reported sleepiness and objective measures of fatigue
    • alcohol intake causes sleep fragmentation and decreased REM sleep - hence one feels tired the next day
    • most sedative-hypnotics disrupt sleep architecture and are associated with impaired quality of sleep
      • 250mg improves psychomotor performance if sleep deprived but 500mg gives no further improvement but adds side effects
      • brewed coffee has ~135mg, while tea has 35-50mg.
      • benefit subject to tachyphylaxis
      • constant high doses may cause withdrawal headaches
      • adversely effects sleep latency and sleep quality
    • micro-awakenings decrease time in slow wave sleep and decrease time in REM sleep
    • a regular siesta may reduce coronary mortality by 37% 1)
    • the only way to reverse the need for sleep is to sleep
  • insomnia or difficulty in getting to sleep is a symptom and thus a cause should be sought

Aetiology:

psychiatric factors:

environmental factors:

  • bedroom too hot, too cold, too noisy (eg. crying baby, restless child, partner with snoring)
  • bed cramped or uncomfortable

physical factors:

disturbed sleep cycles:

  • delayed sleep phase disorder
    • the main cause in perhaps 15% of people with insomnia
    • hard to get to sleep before 2am and hard to wake up early
    • may respond to metatonon or agomelatine (Valdoxan), a new antidepressant which also acts on melatonin receptors to cause a phase advance.
  • lack of daytime exercise
  • inadequate daytime exposure to light
  • excessive time in bed
  • jet lag

Clinical approach:

  • consider pt maintaining a sleep log to help ascertain extent & type of disturbance
  • managing insomnia in older people:
    • discuss & agree on therapeutic objectives with the patient
    • assess the complaint - what is causing it?
    • treat or improve the underlying cause
    • educate the patient about good sleep habits - see behavioural Rx below
    • avoid use of hypnotic drugs whenever possible as adverse effects usually outweigh benefits except perhaps in short term usage, when prescriptions should be only for 2 weeks maximum
      • for every 13 patients aged over 60 years treated with hypnotics, it will improve sleep in 1 person but will cause an adverse effect (cognitive impairment, falls. fractures, motor vehicle accidents) in 2 people

behavioural Rx of insomnia:

  • see sleep hygiene to ensure lifestyle maximises probability of quality sleep
  • consider anxiety management & relaxation techniques if pts worried & anxious they will not be able to get to sleep
  • consider cognitive behavioural therapy techniques
    • replace distorted beliefs and attitudes with positive ones
      • reassure that less than 8 hours sleep per night is not necessarily detrimental
  • address learned association between going to bed and being unable to sleep
    • go to bed only when tired, and only use bed for sex or sleep
    • get out of bed if not asleep within a perceived 20 minutes - but DO NOT watch the clock
    • repeat each night until a stable sleep-wake schedule is established
    • restrict sleep time in bed to actual sleep duration (but at least 5 hours sleep) and have a set wake up time

drug Rx of insomnia:

  • if hypnotics must be used, use them only 2-5 times per week and for less than 2 weeks duration
    • long half-life benzodiazepines (esp. in elderly) result in increased risk of:
      • confusion, drowsiness, memory loss, unsteadiness, falls (thus hip fractures) & incontinence
      • doubles risk of road traffic accidents in all age groups, but in addition, in persons over 65yrs, have an additional 50% risk if brief duration Rx or 30% risk if long term Rx.
      • most benzodiazepines lose their hypnotic efficacy after approx. 14 consecutive nights, even though people still keep taking them
      • quality of sleep is modified - less deep & relaxed sleep; tendency to fall asleep & awake earlier;
      • day-time: feelings of tiredness; lack of energy; mood disturbances;
  • the 'Z drugs':
    • act on same receptor as benzodiazepines
    • said to have less adverse effects & less dependency than benzodiazepines, but these are still present
    • zolpidem has caused delirium, hallucinations, nightmares & hip fractures (2x risk of no Rx & more than Rx with benzo's, anti-psychotics or antidepressants)
    • zopiclone:
      • causes hangover effects & impairs psychomotor performance similar to temazepam & nitrazepam
      • has bitter taste
    • zaleplon:
      • short half-life, thus useful for sleep-onset insomnia
  • valerian:
    • herbal extract with mild hypnotic activity, but limited studies as yet.
  • melatonin:
    • a naturally occurring hormone secreted from pineal gland
    • widely used to regulate sleep-awake cycles in circadian-based disorders such as jet lag
    • adverse effects: enhanced immune functioning, vasoconstriction, exacerbation depression
    • should not be used to Rx insomnia unless concurrent depression
    • should not be used as cause anticholinergic effects & confusion, esp. in children & elderly & tolerance develops quickly

ceasing hypnotic medications

  • prolonged Rx with hypnotic medications for > 4 weeks increases risk of dependence
  • this is particularly a problem with the elderly who are most at risk of adverse effects such as increased falls
  • rebound insomnia may occur even with short term hypnotic use of less than 2 weeks and thus gradual dose reduction may be needed

step 1 - raise awareness of the need to stop

  • provision of a letter advising cessation combined with self-help advice doubles the chances of a patient wishing to cease Rx

step 2 - STOP guide to reducing hypnotic Rx

  • see NPS 2)
Share views and agree on a stopping plan
  • discuss goals for stopping or reducing use
  • agree on rate and duration of cessation
  • outline the type, nature and expected duration of withdrawal symptoms
  • advise on strategies to Mx withdrawal symptoms
Taper dosage gradually
  • modify dose and/or frequency based on severity of withdrawal symptoms
  • all time to stabilise between dosage reductions - at least a few days
  • consider referral to a specialist if dose reduction proves too difficult
  • example reduction of benzodiazepines:
    • reduce dose by 10-20% per week if it is within or slightly above the recommended dose
    • stabilise on an equivalent dose of diazepam (unless elderly) for a few days before dose reduction if patient was on a higher than recommended dose or finding it difficuklt to wean a short-acting agent.
    • if multiple benzodiazepines are used, the dose of each drug may be reduced one after the other
Ongoing review
  • weekly monitor effect of cessation on sleep patterns, mood, withdrawal symptoms and use of other substances (eg. alcohol, caffeine)
  • encourage use of non-drug therapies
  • suggest coping strategies
Provide support and reassurance
  • engage family, carers, staff in residential facilities
  • if unsuccessful, reassure that further attempts are worthwhile
  • repeat STOP steps when patient willing to try again
n_insomnia.txt · Last modified: 2013/08/24 01:20 by gary1