Pharmacology for Paramedics Flashcards

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

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.

Morphine sulphate's primary mechanism of action in pain management is:

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.

The correct pre-hospital dose of aspirin for suspected STEMI is:

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.

Glucagon's mechanism of action in hypoglycaemia treatment is:

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.

Ipratropium bromide is used in acute severe asthma to:

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.

The reversal agent for benzodiazepine overdose is:

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.