Revision - Overdoses Flashcards
What class of a
drug is dosulepin?
TCA
What 2 neurotransmitters do TCAs have an INCREASED effect on (i.e. via reuptake inhibition)?
1) serotonin (5-HT)
2) noradrenaline
What 2 neurotransmitters do TCAs have a DECREASED effect on (i.e. via postsynaptic receptor antagonism)?
1) acetylcholine
2) histamine (h1)
3) a-1 adrenoreceptors
What 3 ECG changes may be seen in TCA overdose?
1) sinus tachycardia
2) QT prolongation
3) QRS widening
What are the 3 hallmark features of serotonin syndrome?
1) altered mental state
2) neuromuscular hyperactivity –> myoclonus, hyperreflexia
3) autonomic hyperactivity –> tachycardia, sweating, HTN
How is potassium level affected by TCA overdose?
Causes hypokalaemia –> risk of seizures or cardiac arrhythmias
1st line medical management of hypotension or arrhythmias in TCA overdose?
IV bicarb
Indications for IV bicarb in TCA overdose?
ECG changes
Give 2 drugs that are contraindicated in TCA overdose?
1) Flecainide
2) Amiodarone (prolongs QT interval)
Pulse in salicylate OD?
Bounding pulse
Management of salicylate overdose?
1) ABCDE
2) Supportive care (consider ICU admission)
3) Activated charcoal: if presenting within 1 hour of ingestion
4) Fluids
5) Urinary alkalisation w/ sodium bicarb
6) Haemodialysis
Purpose of IV sodium bicarb in salicylate overdose?
enhances elimination of aspirin in the urine
How does salicylate overdose affect body temp?
Hyperthermia
What can cause hyponatraemia in ecstasy poisoning?
1) SIADH
2) Excessive water drinking
What can be used for mx of hyperthermia in ectasy poisoning if simple measures fail?
Dantrolene
Give some drugs that can cause serotonin syndrome
1) MOAIs
2) SSRIs
3) Ecstasy
4) Amphetamines
What are 2 key drugs that can interact with SSRIs are cause serotonin syndrome?
1) Tramadol
2) St John’s Wort
Management of serotonin syndrome?
1) supportive
2) benzos
Dose of naloxone in opioid overdose?
400 micrograms (IV, IM or SC)
What 2 medications are used in opioid detoxification?
1) methadone
2) buprenorphine
What is the key investigation in opioid overdose?
ABG –> to assess the degree of type 2 respiratory failure 2ary to respiratory depression.
How does a benzo OD affect pupils?
dilated
medical mx of benzo OD?
Flumenazil
What is flumenazil?
GABA antagonist
When should flumenazil be used in a benzo overdose?
1) CNS depression is severe enough that patients are requiring ventilation
2) You are confident that ONLY benzos have been taken (e.g. no possibility of a mixed overdose)
3) The patient is not known to be benzo dependent
What is the risk of using flumenazil in a benzo OD outside of these conditions?
Risks precipitating seizures (e.g. if a patient has also taken TCAs) which are particularly difficult to treat due to the GABA antagonism caused by flumazenil.
How does a benzo overdose typically affect body temp?
Hypothermia
