📈 QT Prolongation Risk & High-Risk Drugs
Quick reference to QT-prolonging drug classes, modifiable and patient risk factors, and management thresholds for torsades (TdP). Browser-side.
QT Prolongation Risk & High-Risk Drugs
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When to use
Bedside risk awareness before prescribing QT-prolonging agents. Look up authoritative per-drug ratings at CredibleMeds; compute the QTc value with this site's QTc tool.
How it works
Prolonged: men > 450 ms, women > 470 ms. High-risk: QTc > 500 ms or +60 ms from baseline. Keep K⁺ > 4.0 mmol/L and Mg²⁺ > 2.0 mg/dL.
Key points
- Risk multiplies when drug, electrolyte and patient factors stack.
- Correcting hypokalaemia/hypomagnesaemia and bradycardia markedly lowers TdP risk.
- Treat TdP with IV magnesium; consider pacing/isoprenaline.
- Avoid combining multiple QT-prolonging drugs.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.