Safe Prescribing — Flashcards

Flashcard 91: The first line managment of TCA overdose is _____

Answer: IV hypertonic sodium bicarbonate

Flashcard 92: _____ and hypomagnesaemia may occur in patients with digoxin toxicity

Answer: Hyperkalaemia

Extra: Digoxin toxicity: 1. Causes **hyperkalaemia** (blocks Na+/K+ ATPase, preventing K+ entry into cells). 2. **Hypomagnesaemia** increases sensitivity to digoxin, increasing risk of toxicity. 3. Note: While hyperkalaemia is a *consequence*/prognostic marker of toxicity, hypokalaemia and hypomagnesaemia *exacerbate* the effect of digoxin.

Flashcard 93: What is the mechanism of digoxin? _____

Answer: Inhibits the Na+/K+ pump → Increased intracellular Ca2+ → Increased force of contraction Decreases AV node conduction → Decreases heart rate

Flashcard 94: _____ may be used with senior support AND extreme caution in patients with TCA toxicity if IV hypertonic sodium bicarbonate fails

Answer: Class Ib anti-arrhythmics (e.g., Lidocaine)

Extra: Class Ia and Ic anti-arrhythmics are contraindicated in TCA toxicity as they further prolong the QRS interval and worsen sodium channel blockade. Lidocaine (Class Ib) is sometimes considered in refractory arrhythmias.

Flashcard 95: Management of hypokalaemia/hypomagnesaemia in digoxin toxicity should be with _____ and intravenous Mg2+

Answer: intravenous K+

Flashcard 96: _____ can be taken in suspected digoxin toxicity if it was taken within the last 1-2 hours

Answer: Activated charcoal

Flashcard 97: Patients with suspected serotonin syndrome may be given _____ if they have taken the causative drug within the past 1-2 hours

Answer: activated charcoal

Flashcard 98: cyproheptadine is a _____

Answer: 5-HT2A receptor antagonist

Flashcard 99: TCA toxicity causes inhibition of _____ receptors, muscarinic receptors, histamine receptors, sodium channels

Answer: alpha-adrenergic

Flashcard 100: Inhibition of _____ enzymes in patients taking serotonergic drugs may cause serotonin syndrome

Answer: CYP450