Pharmacology Flashcards

A patient in a Saudi hospital ICU is receiving IV vancomycin 1g every 12 hours for MRSA bacteremia. The pharmacist reports a trough level of 22 mg/L (target: 10–20 mg/L). The patient's serum creatinine has risen from 62 to 104 µmol/L over 48 hours. Which is the MOST appropriate nursing action?

Answer: Hold the next dose and notify the physician immediately, documenting signs of nephrotoxicity

A supratherapeutic vancomycin trough (>20 mg/L) combined with a rising serum creatinine (≥1.5× baseline, per KDIGO criteria) indicates vancomycin-induced nephrotoxicity. The next dose must be held and the prescribing physician notified immediately so dose adjustment or drug discontinuation can be ordered. Continuing the infusion at any rate without medical review is unsafe. Oral vancomycin has negligible systemic absorption and is only used for Clostridioides difficile colitis — not systemic MRSA infections.

A nurse in a Riyadh tertiary hospital is preparing to administer sodium nitroprusside to a hypertensive emergency patient. After 72 hours of continuous infusion at 4 mcg/kg/min, the patient develops tachycardia, metabolic acidosis (pH 7.28), and altered consciousness despite a controlled blood pressure. Which toxicity should the nurse suspect, and what is the SCFHS-recognized antidote?

Answer: Cyanide toxicity; treat with hydroxocobalamin IV

Prolonged nitroprusside infusions (>48–72 hours) or high rates (>2 mcg/kg/min) can lead to cyanide accumulation as the drug degrades. Cyanide inhibits cytochrome oxidase, causing cellular hypoxia manifesting as metabolic (lactic) acidosis, tachycardia, and altered consciousness despite adequate BP control. Hydroxocobalamin (Cyanokit®) is the first-line antidote — it binds cyanide to form cyanocobalamin, which is renally excreted. Sodium thiosulfate treats thiocyanate-related toxicity (a separate, slower-onset complication in renal failure). Methylene blue treats methemoglobinemia, not cyanide poisoning.

A post-operative patient in a Saudi hospital is receiving a heparin infusion per the institutional protocol. A STAT aPTT returns at 180 seconds (therapeutic range: 60–100 seconds). The patient shows no active bleeding. According to standard weight-based heparin dosing protocols used in Saudi MOH facilities, what is the CORRECT nursing intervention?

Answer: Stop the infusion for 30 minutes, then restart at a rate reduced by 3 units/kg/hr

Most Saudi MOH and CBAHI-accredited hospital weight-based heparin protocols align with international guidelines (e.g., Raschke nomogram): for aPTT >120 seconds with no active bleeding, the standard action is to hold the infusion for 30 minutes and then restart at a rate reduced by 3 units/kg/hr (approximately a 25–30% rate reduction). Stopping for a full hour with a 20% reduction is excessive. Protamine sulfate is reserved for reversal in cases of significant or life-threatening hemorrhage — not for asymptomatic supratherapeutic levels. Simply continuing without adjustment ignores a critically elevated aPTT.

A nurse is preparing a morphine PCA for a 68-year-old patient with chronic kidney disease (eGFR 18 mL/min/1.73m²) post-abdominal surgery. The physician orders morphine 1 mg demand dose with a 10-minute lockout. What is the PRIMARY pharmacokinetic concern specific to this patient?

Answer: Accumulation of morphine-6-glucuronide causing prolonged and exaggerated opioid effects

Morphine is hepatically metabolized to morphine-3-glucuronide (M3G, which is inactive but may cause neuroexcitatory effects) and morphine-6-glucuronide (M6G). M6G is a potent active opioid metabolite that is renally excreted. In patients with severe CKD (eGFR <30), M6G accumulates significantly, leading to prolonged sedation, respiratory depression, and exaggerated opioid toxicity — even at standard doses. This is why alternative opioids such as hydromorphone (with monitoring) or fentanyl are often preferred in advanced renal impairment in Saudi clinical practice. Morphine PCA in this patient requires extreme vigilance and likely dose reduction or agent substitution.

During Ramadan, a Saudi patient with type 2 diabetes mellitus and stable heart failure is managed with metformin, empagliflozin, and bisoprolol. The patient asks the nurse about their medications during the fasting period. Which statement by the nurse is MOST pharmacologically accurate?

Answer: Empagliflozin should be temporarily discontinued during Ramadan fasting due to risk of euglycemic diabetic ketoacidosis, which may be exacerbated by dehydration and carbohydrate restriction

SGLT2 inhibitors such as empagliflozin carry a risk of euglycemic diabetic ketoacidosis (euDKA) — a serious complication where DKA occurs with near-normal blood glucose levels, making it easy to miss. Ramadan fasting creates the perfect storm for euDKA: prolonged carbohydrate restriction, relative dehydration, and altered dietary patterns all trigger ketogenesis. Saudi Diabetes Society and international Ramadan-specific diabetes guidelines recommend considering temporary suspension of SGLT2 inhibitors during Ramadan. Metformin does not cause lactic acidosis in well-hydrated patients with adequate renal function — it is generally continued with adjusted timing. Bisoprolol doses must never be arbitrarily doubled; dose redistribution requires physician guidance. Stating no monitoring is required is clinically dangerous.

A nurse administers IV magnesium sulfate 4g over 20 minutes as a loading dose to a preeclamptic patient in a Saudi maternity hospital. Thirty minutes later, the patient's respiratory rate is 10 breaths/min, deep tendon reflexes are absent, and urine output is 15 mL over the past hour. What is the nurse's PRIORITY intervention, in the correct sequence?

Answer: Stop the MgSO₄ infusion → call the physician → prepare calcium gluconate 1g IV for immediate administration

The clinical picture — RR <12, absent DTRs, and oliguria — represents magnesium toxicity. The correct sequence per Saudi MOH obstetric emergency protocols is: (1) STOP the magnesium infusion immediately; (2) notify the physician urgently; (3) prepare calcium gluconate 1g (10 mL of 10% solution) IV for administration as directed by the physician. Calcium gluconate — NOT calcium chloride — is the preferred antidote in obstetrics because calcium chloride is caustic if it extravasates and is reserved for cardiac arrest contexts. Administering the antidote before physician notification or before stopping the causative agent violates the correct management sequence. Merely reducing the infusion rate is inadequate for overt toxicity.