Toxicity Article Flashcards
T/F
Sedatives(hypnotics) are contraindicated for insomnia.
False
they can treat insomnia
Anxiolytics and Sedative-Hypnotics
drug families
benzos
nonbenzodiazepine receptor agonists
opiates
melatonin agonists
antidepressants
antipsychotics
anticonvulsants
barbiturates
antihistamine
Anxiolytics and Sedative-Hypnotics exert their most significant effect on the ____.
central nervous system
most common etiologies for anxiolytic & sedative toxicity
improper dosing
misuse/abuse
drug-drug interactions
use of diazepam 5 to 10 mg in an older person with liver disease causing build-up & toxic side effects (sedation and falls)
improper dosing
fluvoxamine inhibits the metabolism of ___
alprazolam (xanax)
results in build-up in the blood –> sedation
fluvoxamine is a(n) ….
3A4 inhibitor
(SSRI; often used for OCD)
use of benzodiazepines or barbiturates with alcohol
enhance intoxication
unintended respiratory depression & death
more commonly abused anxiolytic
benzodiazepine class
highest rate of misuse of benzos
Adults 18 to 49
Age group most often prescribed benzodiazepines
adults 50 to 65
lifetime prevalence of anxiolytic and sedative use disorders in the US
(%)
1.0 and 1.1%
prevalence of anxiolytic and sedative use disorder in the USA
0.16% of the total population
6% of ppl w/ concomitant illicit drug use disorder
Anxiolytic and sedative toxicity
Risk factors
White race
Female sex
Uninsured
Unemployed
Panic symptoms
Other psychiatric symptoms
Alcohol abuse or dependence
Cigarette use
Illicit drug use
History of IV drug use
Benzodiazepines (BZDs) & barbiturates MoA
gamma-aminobutyric acid type A (GABA-A) receptor agonists
T/F
GABA-A receptors are metabophores.
False
ligand-gated chloride ion channels
influx of Cl-
BZDs and barb increase GABA’s inhibitory effect by…
increasing the frequency and time of channel openings
T/F
Nonbenzodiazepine receptor agonists are nonselective.
False
selectively target one type of GABA-A receptor
T/F
Nonbenzodiazepine receptor agonists are structurally different than BZDs.
True
different chemical structure
T/F
Melatonin agonists have high affinity for MT.
False
slight affinity to MT
MT location
suprachiasmatic nucleus (hypothalamus)
Antihistamines target ___ receptors in the …
H1
gastrointestinal, blood vessel, and respiratory tracts
T/F
Opiates act on multiple receptors, both centrally and peripherally.
True
Opiates MoA
Increases dopamine thru GABA, which opposes the natural inhibition of dopamine release
(release dopamine by enhancing GABA disinhibition of dopamine release)
receptor responsible for pain relief and euphoria, & respiratory depression
mu
receptors affected by opioids
mu, kappa, and sigma
Why does opioid overdose result in respiratory depression, coma, and death?
opioids affect the mu receptor, which causes respiratory depression
T/F
Antidepressants cause sedation
True
How do antidepressants and antipsychotics cause sedation?
antihistamine H1 blockade
Anticonvulsants cause sedation by…
enhance GABA neurotransmission
(self-poisoning)
more likely to have a fatal outcome compared to diazepam
temazepam and zopiclone/zolpidem
Carbamazepine was over twice as like to result in death compared to ___
lithium
Which was more likely to result in death?
Clozapine
chlorpromazine
Clozapine
Which is less toxic?
Risperidone
chlorpromazine
Risperidone
T/F
overdose of oral BZDs rarely cause toxicity
True
unless co-ingested with another agent
most common presentation of BZD toxicity
CNS depression
stable vital signs
drowsy but arousable
can give history
most intentional overdoses with BZDs occur with ___ co-ingestion
ethanol
Severe toxicity
stuporous or comatose
Which class is more often associated with complex-sleep related behaviors?
NonBZD hypnotics
Complex-sleep related behaviors are more common with which sleeping drugs?
zolpidem
zaleplon
eszopiclone
Complex-sleep related behaviors
sleepwalking/driving/eating
and other behaviors that can be completed while not fully awake
T/F
Nearly all fatal overdoses of SSRI/SNRIs involve the co-ingestion of another substance or massive quantities.
True
Overdoses associated with SSRI/SNRIs rarely cause death or serious injury
serotonin syndrome
overstimulation of central and peripheral serotonin receptors
serotonin syndrome
S/S
anxiety, agitation, delirium, diaphoresis, tachycardia, hypertension, hyperthermia, gastrointestinal distress, tremor, muscle rigidity, myoclonus, and hyperreflexia
SSRI/SNRIs that can precipitate seizures
bupropion and venlafaxine
(status epiltcs rare)
Patients may initially present normally and then deteriorate rapidly due to the variable absorption kinetics involved in ___
TCAs
anticholinergic toxicity can occur with overdose of which drug class
TCAs
TCA overdose
AMS
sedation
confusion
delirium
hallucination
cardiac conduction delays
arrhythmias
hypoTN
anticholinergic toxicity
anticholinergic toxicity
S/S
hyperthermia
flushing
pupillary dilation
T/F
Normal pupils can rule out a diagnosis of opiate toxicity
False
T/F
Opiate OD is always accompanied by bradycardia.
False
Heart rate ranges from bradycardia to tachycardia
Hypotension in opiate OD results from…
histamine release
Hypothermia in opiate OD results from…
impaired thermogenesis or environmental exposure.
antiseizure drugs
most severe reactions
suicidality
severe skin reactions:
-Stevens-Johnson synd (SJS)
-toxic epiderm necrolysis (TEN)
-drug reaction with eosinophilia and systemic symptoms (DRESS)
T/F
We can obtain a reliable history in patients who intentionally ingested medication in an attempt to commit suicide
False
History is often unreliable in this case
T/F
Assessing odor & skin changes can help identify the potential intoxicant.
True
What to look for on an EEG in an OD pt.
QRS and QTc intervals
anxiolytics, sedatives, & TCAs can prolong the QRS
antipsychotics prolong QT
Some antipsychotic drugs ___ the QT interval due to…
blocking K efflux
Toxin-induced QRS interval prolongation occurs in
TCA poisoning
immediate action is necessary!
Cons of toxicological screening
false +’s
first priority
ensure hemodynamically stable
specific attention to the airway, breathing, and circulation
BZD toxicity treatment
supportive care
close monitoring (unless the toxicity is severe)
Airway protection
most important in BZD toxicity treatment
Airway protection
End-tidal CO2 monitoring can be useful to monitor those at risk of
hypoventilation
T/F
activated charcoal is ideal for isolated BZD overdose
False
can cause aspiration
flumazenil
nonspecific competitive antagonist for the BZD receptor
reverse BZD-induced sedation following GA, procedural sedation, or OD
flumazenil controversy
risk withdrawal seizures in patients w/ tolerance for BZDs
esp w/ concomitat pro-convulsants
Is it safe to give flumazenil to patients who have a chronic use of BZDs?
Not always
risk withdrawal seizures in patients w/ tolerance for BZDs
SSRI/SNRI treatment
monitoring for:
serotonin syndrome
seizures
cardiac conduction abnormalities
-QT prolongation
given or those with signs of serotonin syndrome or seizures
BZDs
given for those with cardiac toxicity
Sodium bicarbonate
risk of developing torsades de pointes
Magnesium sulfate intravenously
TCA toxicity
QRS interval >100 msec or ventricular arrhythmia
treatment?
Sodium bicarbonate
use of activated charcoal is permitted in which OD?
TCA
BZDs
opiates
SSRI/SNRI
TCA
TCA OD
activated charcoal is recommended within ___ hours of ingestion.
2
(Unless bowel obstruction, ileus, or perforation)
naloxone
short-acting opiate antagonist
preferred admin route for naloxone
IV
Differential diagnosis may be broad d/t…
pts unable to contribute to a meaningful history
If the patient overdosed intentionally, history becomes (more/less) reliable.
less
Differential diagnosis is broad and can consist of which causes?
metabolic
structural
infectious causes
Hypoglycemia
Secondary complications that may make the effects of an OD permanent
cerebral ischemia
cardiac ischemia
T/F
Early treatment of an overdose may result in no long-term complications.
True
