DCAS Pharmacology for Paramedics 1 — Questions and Answers
Question 1: The therapeutic effect of adenosine in SVT relies on its ability to:
- Transiently block AV nodal conduction, terminating re-entrant circuits (Correct answer)
- Permanently slow the heart rate
- Cause calcium channel blockade
- Increase cardiac contractility
Correct answer: Transiently block AV nodal conduction, terminating re-entrant circuits
Adenosine binds A1 receptors in the AV node, causing transient (10-15 second) complete AV block that interrupts the re-entrant circuit maintaining most SVTs, allowing sinus rhythm to resume.
Question 2: Morphine sulphate's primary mechanism of action in pain management is:
- Binding to mu-opioid receptors in the CNS and peripheral nervous system to reduce pain perception (Correct answer)
- Blocking sodium channels in pain nerve fibres
- Inhibiting prostaglandin synthesis
- Causing muscle relaxation to reduce spasm pain
Correct answer: Binding to mu-opioid receptors in the CNS and peripheral nervous system to reduce pain perception
Morphine binds primarily to mu-opioid receptors in the brain, spinal cord, and peripheral tissues, reducing the perception of pain and the emotional response to pain, while also causing sedation and respiratory depression.
Question 3: The correct pre-hospital dose of aspirin for suspected STEMI is:
- 300mg (chewed, not swallowed whole, for rapid absorption) (Correct answer)
- 75mg oral
- 600mg IV
- 150mg sublingual
Correct answer: 300mg (chewed, not swallowed whole, for rapid absorption)
Aspirin 300mg chewed (not swallowed whole) achieves faster absorption and platelet inhibition through COX-1 inhibition, reducing further thrombus formation in suspected acute coronary syndrome.
Question 4: Glucagon's mechanism of action in hypoglycaemia treatment is:
- Stimulating glycogenolysis in the liver, raising blood glucose — independent of beta-adrenoceptors (Correct answer)
- Direct glucose supplementation
- Stimulating pancreatic insulin secretion
- Inhibiting glucose uptake by cells
Correct answer: Stimulating glycogenolysis in the liver, raising blood glucose — independent of beta-adrenoceptors
Glucagon binds to hepatic receptors, activating adenylate cyclase to promote glycogenolysis (glycogen breakdown to glucose) and gluconeogenesis, raising blood glucose independent of the insulin or adrenergic systems.
Question 5: Ipratropium bromide is used in acute severe asthma to:
- Provide additional bronchodilation through muscarinic (cholinergic) receptor blockade, complementing beta-2 agonist therapy (Correct answer)
- Replace salbutamol in mild asthma
- Provide systemic anti-inflammatory effects
- Prevent mast cell degranulation
Correct answer: Provide additional bronchodilation through muscarinic (cholinergic) receptor blockade, complementing beta-2 agonist therapy
Ipratropium blocks muscarinic receptors in the airway, reducing bronchoconstriction via a different pathway from beta-2 agonists, providing additive bronchodilation when combined with salbutamol in severe asthma.
Question 6: The reversal agent for benzodiazepine overdose is:
- Flumazenil — competitive GABA-A receptor antagonist (Correct answer)
- Naloxone — opioid receptor antagonist
- Physostigmine — anticholinesterase
- Atipamezole — alpha-2 antagonist
Correct answer: Flumazenil — competitive GABA-A receptor antagonist
Flumazenil competitively antagonises benzodiazepines at GABA-A receptors, reversing sedation and respiratory depression; its short half-life means re-sedation can occur, requiring monitoring.
DCAS Pharmacology for Paramedics 1
The therapeutic effect of adenosine in SVT relies on its ability to: