Revision - Overdoses

Question 1

What class of abx is dosulepin?

Answer 1

Anticholinergic

Question 2

What 2 neurotransmitters do TCAs have an INCREASED effect on (i.e. via reuptake inhibition)?

Answer 2

1) serotonin (5-HT)

2) noradrenaline

Question 3

What 2 neurotransmitters do TCAs have a DECREASED effect on (i.e. via postsynaptic receptor antagonism)?

Answer 3

1) acetylcholine

2) histamine (h1)

3) a-1 adrenoreceptors

Question 4

What 3 ECG changes may be seen in TCA overdose?

Answer 4

1) sinus tachycardia

2) QT prolongation

3) QRS widening

Question 5

What are the 3 hallmark features of serotonin syndrome?

Answer 5

1) altered mental state

2) neuromuscular hyperactivity –> myoclonus, hyperreflexia

3) autonomic hyperactivity –> tachycardia, sweating, HTN

Question 6

How is potassium level affected by TCA overdose?

Answer 6

Causes hypokalaemia –> risk of seizures or cardiac arrhythmias

Question 7

1st line medical management of hypotension or arrhythmias in TCA overdose?

Answer 7

IV bicarb

Question 8

Indications for IV bicarb in TCA overdose?

Answer 8

ECG changes

Question 9

Give 2 drugs that are contraindicated in TCA overdose?

Answer 9

1) Flecainide

2) Amiodarone (prolongs QT interval)

Question 10

Pulse in salicylate OD?

Answer 10

Bounding pulse

Question 11

Management of salicylate overdose?

Answer 11

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

Question 12

Purpose of IV sodium bicarb in salicylate overdose?

Answer 12

enhances elimination of aspirin in the urine

Question 13

How does salicylate overdose affect body temp?

Answer 13

Hyperthermia

Question 14

What can cause hyponatraemia in ecstasy poisoning?

Answer 14

1) SIADH

2) Excessive water drinking

Question 15

What can be used for mx of hyperthermia in ectasy poisoning if simple measures fail?

Answer 15

Dantrolene

Question 16

Give some drugs that can cause serotonin syndrome

Answer 16

1) MOAIs

2) SSRIs

3) Ecstasy

4) Amphetamines

Question 17

What are 2 key drugs that can interact with SSRIs are cause serotonin syndrome?

Answer 17

1) Tramadol

2) St John’s Wort

Question 18

Management of serotonin syndrome?

Answer 18

1) supportive

2) benzos

Question 19

Dose of naloxone in opioid overdose?

Answer 19

400 micrograms (IV, IM or SC)

Question 20

What 2 medications are used in opioid detoxification?

Answer 20

1) methadone

2) buprenorphine

Question 21

What is the key investigation in opioid overdose?

Answer 21

ABG –> to assess the degree of type 2 respiratory failure 2ary to respiratory depression.

Question 22

How does a benzo OD affect pupils?

Answer 22

dilated

Question 23

medical mx of benzo OD?

Answer 23

Flumenazil

Question 24

What is flumenazil?

Answer 24

GABA antagonist

Question 25

When should flumenazil be used in a benzo overdose?

Answer 25

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

Question 26

What is the risk of using flumenazil in a benzo OD outside of these conditions?

Answer 26

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.

Question 27

How does a benzo overdose typically affect body temp?

Answer 27

Hypothermia