ic14 sleep disorders Flashcards
what are the features of the physiological sleep wake cycle (duration, reset, hormones involved, NT involved, sleep states and specific stages, number of cycles and duration of each cycle)
24h, resetting of internal clock by cues like day light
hormone: melatonin secretion incr during sleep and is suppressed by bright light
NT: [sleep promoting] GABA [wake promoting] NE, DA, ACh, histamine, orexin
GABA is an inhibitory NT, NE incr HR, DA incr alertness (or even psychotic), histamine (recall antihistamine makes you sedated and sleepy)
sleep states: [wakefulness] [non rapid eye movement (NREM) sleep] 75% of total sleep time (TST), decr in HR RR and BP, stage 1 is light sleep which accounts for 5% of TST where sleep initiation over 15-30mins occurs; stage 2 is deeper sleep which accounts for 45% of TST; stage 3 and 4 is delta sleep/ restorative sleep (aka deep sleep) which accounts for 25% of TST, release of growth hormone, restore protein synthesis, wound healing, immune func [rapid eye movement (REM) sleep] 25% of TST (approx q90min) BP HR and RR can fluctuate and become irregular, dreaming, memory consolidation, sensorimotor development, nocturnal erection
cycles: 4-6cycles/night, 70-120min per cycle
what is “insomnia disorder”
inability to initiate or maintain sleep, assoc w daytime problems like fatigue, impaired conc and memory
what is the DSM-5 diagnostic criteria for insomnia disorder
(A) primary complaint of unsatisfying sleep quantity or quality with presence of 1 or more of the following: difficulty with sleep initiation, difficulty with sleep maintenance, early morning awakening
(B) complaint usually assoc w social, occupational, academic, educational, behavioural or func distress or impairment
(C) sleep complaint occurs at least 3 nights per week and has been present for at least 3m
(D) sleep difficulties occur even with ample opportunity to sleep
(E) sleep complaint not attributed to or explained by another sleep-wake disorder, s/e of medication or substance, or coexisting psychiatric illness or medical condition
(F) can be further specified using duration
(i) episodic: 1m to <3m
(ii) persistent: 3m and longer
(iii) recurrent: experience at least 2 episodes within 1yr
compared to using DSM-5 to classify insomnia as a disorder, what is the method that is more commonly adopted (types, likely causes, management)
more commonly adopted to take insomnia as a symptom
- acute if experiences sleep difficulties for one night to a few weeks; considered acute transient if only lasted for <1w and considered acute short term if lasted for <4w; likely caused by acute stressors; [acute transient] manage with sleep hygiene and is self-limiting [acute short term] sleep hygiene and can consider short term hypnotics (7-10d up to 2-4w)
- chronic if experiences sleep difficulties on at least 3 nights per week for 1m or longer (aka last for >4w); causes incl secondary to underlying psychiatric or medical condition, poor sleep hygiene, substance abuse, primary sleep disorders (sleep apnea, restless leg syndrome); manage by investigating and managing underlying causes or conditions, and with sleep hygiene and discourage long term use of hypnotics
what are the non pharmacotx for insomnia
non pharmacotx is recommended by tx guidelines as effective standard of care
- CBT-insomnia
- relaxation training
- sleep restriction therapy
- stimulus control therapy
- sleep hygiene
what are the pharmacotx for insomnia (differentiate between the general types of agents)
fast acting anxiolytics/ hypnotics/ sedatives are intended only as ADJUNCT for SHORT TERM relief of DISTRESSFUL insomnia or anxiety at PRN and LOWEST effective dose for SHORT COURSE (1-2w)
i) anxiolytics (aka sedatives) are agents that induces sleep when given at night
ii) hypnotics are agents that sedate when given in the day
iii) antipsychotics are agents that tranquilise without impairing consciousness or causing paradoxical excitement (to calm disturbed pts)
what is the first line tx for insomnia (elaborate)
sleep hygiene
i) avoid caffeine containing products, nicotine and alcohol esp later in the day
ii) avoid heavy meals within 2hrs before bedtime
iii) avoid drinking plenty fluids after dinner to prevent freq night time urination
iv) avoid environments that will make you really active after 5pm (noisy environments)
v) ensure bed is only for sleep, use sofa for relaxation
vi) avoid watching TV in bed
vii) set a regular routine to get ready for bed
viii) provide yourself with ample time to relax before bed (practice relaxation techniques)
ix) set up a conducive environment for sleep (control temperature using blankets, earplugs, darker room)
x) wake up at same time every morning even on weekends (use alarm clock if needed)
xi) relax and think pleasant thoughts when in bed
xii) avoid taking daytime naps (if need do so before 3pm and ensure total nap time <1hr)
xiii) pursue regular physical activities like walking or gardening but avoid vigorous activities close to bedtime
what are eg. of hypnotics (drug classes and drugs, moa, s/e and dose)
- benzodiazepines (lorazepam, diazepam)
i) moa: potentiates GABA
ii) s/e: sedation, drowsiness, amnesia
iii) dose: [lorazepam] 0.5mg [diazepam] 2mg (BUT VERY LONG HALFLIFE thus not for elderly)
*high risk dependence - z-hypnotics (zolpidem, zopiclone)
i) moa: preferentially binds to benzodiazepine binding site with gamma and alpha1 subunits to cause sedation
ii) s/e: taste disturbance for zopiclone, complex sleep behaviours like sleep walking
iii) dose: [zolpidem] IR: 10mg; XR 6.5mg (half dose for females) [zopiclone] 7.5mg; 3.75mg for elderly
*high risk of dependence - antihistamine (promethazine, hydroxyzine)
i) moa: H1 antagonism
ii) s/e: sedation, anticholinergic
iii) dose: promethazine or hydroxyzine 25-50mg ON
*lower risk of dependence - melatonin receptor agonist (circadin; API is melatonin)
i) moa: MT1 and MT2 agonist
ii) s/e: HA
iii) dose: 2mg 1-2hr before bed - orexin receptor antag (lemborexant)
i) moa: OT1 and OT2 receptor antagonist
ii) s/e: somnolence
iii) dose: 5-10mg
iv) c/i in narcolepsy, severe hepatic impairment, moderate to strong cyp3A inhibitor or inducer
what is lemborexant c/i in
lemborexant is a orexin receptor antagonist
c/i in narcolepsy, severe hepatic impairment, moderate to severe cyp3A inducer or inhibitor
what is the c/i for benzodiazepines and z-hyponotics
narrow angle glaucoma, acute pulmonary insufficiency, respiratory depression (asthma and COPD exacerbation), sleep apnea, marked neuromuscular respiratory weakness incl unstable myasthenia gravis
what is the caution of sedating antihistamines
sedating antihistamines incl promethazine and hydroxyzine
anticholinergic s/e incr in prostatic hypertrophy, urinary retention, closed angle glaucoma, pyloroduodenal obstruction, epilepsy, QTc prolongation (for hydroxyzine), CAD (for promethazine)
what are the cautions and c/i for benzodiazepines
c/i in narrow angle glaucoma, acute pulmonary insufficiency, respiratory depression (asthma or COPD exacerbation), sleep apnea, myasthenia gravis, severe renal and hepatic impairment, pregnancy and breastfeeding
caution in children, elderly, renal and hepatic impairment, hx of drug or alcohol abuse or psychiatric disorder
note prolonged use can lead to tolerance and dependence thus avoid and do not abruptly discontinue if not withdrawal (gradual taper by 25% decr weekly until reach 50% dose then decr one eighth every 4-7d)
tolerance developed with weeks or months of high dose daily use
ddi with opioids bc incr mortality
if ECT done, omit benzodiazepine dose before
what is the preferred hypnotic for >55yo
melatonin
what are the pharmacotx adjunctive to if used
antidepressants for MDD or anxiety disorders
what are benzodiazepines effective for
fast onset for physical/ somatic sx like insomnia and muscle tension
