Pharmacology Flashcards

A patient on warfarin therapy is admitted to a Saudi hospital with an INR of 8.2 and active bleeding. According to SCFHS nursing standards, which intervention takes priority?

Answer: Administer vitamin K 10 mg IV slowly and prepare fresh frozen plasma

An INR of 8.2 with active bleeding is a pharmacological emergency. The priority is reversal of anticoagulation using IV vitamin K (which takes 6–12 hours to act) combined with fresh frozen plasma (FFP) for immediate factor replacement. Protamine sulfate reverses heparin, NOT warfarin. Simply withholding the dose is insufficient in the presence of active bleeding.

A nurse in a Saudi MOH hospital is preparing a dopamine infusion for a patient in cardiogenic shock. At a dose of 2 mcg/kg/min, what is the PRIMARY expected pharmacological effect?

Answer: Renal and mesenteric vasodilation via dopaminergic receptors

Dopamine has dose-dependent receptor activity. At low doses (1–5 mcg/kg/min), it primarily stimulates dopaminergic (DA1) receptors, causing renal and mesenteric vasodilation to improve organ perfusion. Beta-1 effects (increased contractility) predominate at moderate doses (5–10 mcg/kg/min), and alpha-1 vasoconstriction dominates at high doses (>10 mcg/kg/min). Dopamine has no clinically significant beta-2 activity.

A patient receiving methotrexate for rheumatoid arthritis presents to a Saudi clinic with severe oral mucositis and fever. Which pharmacological intervention is most appropriate for a nurse to anticipate administering?

Answer: Leucovorin (folinic acid) rescue therapy

Methotrexate inhibits dihydrofolate reductase, depleting active folate and causing mucositis, myelosuppression, and hepatotoxicity in toxicity states. Leucovorin (folinic acid) bypasses the blocked enzyme and directly 'rescues' normal cells — this is standard methotrexate toxicity management. Regular folic acid requires activation by the same blocked enzyme, making it ineffective in acute toxicity. Ondansetron addresses nausea only.

A patient with type 2 diabetes managed with metformin 1000 mg twice daily is scheduled for a contrast CT scan at a Saudi radiology center. Which nursing action regarding metformin is correct according to clinical pharmacology guidelines?

Answer: Hold metformin on the day of the procedure and for 48 hours post-contrast, then check renal function before resuming

Iodinated contrast media can cause acute kidney injury, which reduces metformin clearance and raises plasma lactate, leading to potentially fatal lactic acidosis. Current guidelines recommend holding metformin on the day of contrast administration and for 48 hours post-procedure. Renal function (eGFR) must be reassessed before resuming. This is particularly relevant in Saudi tertiary hospitals where contrast CT is common. Continuing without interruption is dangerous; 5-day pre-hold is excessive and not evidence-based.

A nurse is administering vancomycin 1.5 g IV to a post-operative patient in a Saudi hospital. The patient suddenly develops facial flushing, erythema across the neck and upper torso, and hypotension. No urticaria or bronchospasm is present. What is the MOST likely mechanism and appropriate intervention?

Answer: Red Man Syndrome due to rapid infusion; slow the infusion rate and administer diphenhydramine

Red Man Syndrome (RMS) is a non-immune-mediated anaphylactoid reaction caused by direct mast cell degranulation from rapid vancomycin infusion. It presents with flushing, erythema on the face/neck/upper chest, and hypotension — but WITHOUT urticaria, bronchospasm, or IgE involvement (distinguishing it from true anaphylaxis). Management: stop or slow the infusion, give diphenhydramine IV, and restart at a slower rate (>60–90 minutes per dose). Epinephrine is reserved for true anaphylaxis with bronchospasm or laryngeal edema.

In Saudi Arabia's MOH critical care units, a ventilated patient develops torsades de pointes (TdP) associated with prolonged QTc. The patient is currently on haloperidol, ondansetron, and ciprofloxacin. Which pharmacological intervention is MOST appropriate as first-line treatment for this arrhythmia?

Answer: Magnesium sulfate 2 g IV over 10–15 minutes

Torsades de Pointes is a polymorphic ventricular tachycardia associated with prolonged QTc, often caused by QT-prolonging drugs (haloperidol, ondansetron, and fluoroquinolones like ciprofloxacin all prolong QT). First-line treatment is IV magnesium sulfate 1–2 g over 10–15 minutes, which suppresses early after-depolarizations even in normomagnesemic patients. Amiodarone itself prolongs QT and is CONTRAINDICATED in TdP. Adenosine is for supraventricular tachycardia. Atropine may be used for bradycardia-induced TdP, but is not the first-line pharmacological agent.