DCAS Pharmacology for Paramedics

Question 1

The therapeutic effect of adenosine in SVT relies on its ability to:

Accepted Answer

Transiently block AV nodal conduction, terminating re-entrant circuits

Answer

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:

Accepted Answer

Binding to mu-opioid receptors in the CNS and peripheral nervous system to reduce pain perception

Answer

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:

Accepted Answer

300mg (chewed, not swallowed whole, for rapid absorption)

Answer

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:

Accepted Answer

Stimulating glycogenolysis in the liver, raising blood glucose — independent of beta-adrenoceptors

Answer

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:

Accepted Answer

Provide additional bronchodilation through muscarinic (cholinergic) receptor blockade, complementing beta-2 agonist therapy

Answer

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.

DCAS Practice Test

DCAS Practice Test

DCAS Pharmacology for Paramedics