Pharmacology for Paramedics Flashcards

A patient on chronic lithium therapy presents with nausea, tremor, and altered mental status. This presentation is most consistent with:

Answer: Lithium toxicity

Tremor, nausea, and AMS are classic signs of lithium toxicity, which has a narrow therapeutic index and is worsened by dehydration.

Which opioid analgesic has the longest duration of action and highest risk for prolonged respiratory depression?

Answer: Methadone

Methadone has an extremely long half-life (24-36+ hours), putting patients at risk for delayed respiratory depression after initial dosing.

A paramedic needs to administer 250 mg of a drug supplied as 500 mg/10 mL. What volume should be administered?

Answer: 5 mL

Using the formula: Volume = (Desired dose / Available dose) × Volume on hand = (250/500) × 10 = 5 mL.

Which antidysrhythmic is the FIRST-LINE drug for ventricular fibrillation refractory to defibrillation?

Answer: Amiodarone 300 mg IV bolus

Current AHA guidelines recommend amiodarone 300 mg IV as first-line antidysrhythmic for shock-refractory VF/pulseless VT.

Ondansetron (Zofran) exerts its antiemetic effect by blocking which receptor type?

Answer: Serotonin 5-HT3 receptors

Ondansetron selectively antagonizes 5-HT3 serotonin receptors in the GI tract and chemoreceptor trigger zone to prevent nausea and vomiting.

A patient with a known allergy to aspirin requires antiplatelet therapy after a STEMI. Which agent is most appropriate?

Answer: Clopidogrel (Plavix) 300 mg PO

Clopidogrel is an ADP receptor antagonist (P2Y12 inhibitor) that provides antiplatelet therapy without the cross-reactivity seen with NSAIDs.

Which vasopressor works by releasing norepinephrine from sympathetic nerve terminals rather than directly stimulating adrenergic receptors?

Answer: Ephedrine

Ephedrine is an indirect-acting sympathomimetic that displaces norepinephrine from vesicles at sympathetic nerve terminals.