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Expected pharmacological effect
Causality assessment · Expected pharmacological effect
Nortriptyline and QT prolongation: is the FAERS signal real?
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Nortriptyline ↔ QT prolongation
n=24 co-reports · PRR 2.4 · ROR 2.4
Nortriptyline is the active metabolite of amitriptyline and shares the tricyclic cardiac profile; it produces QT prolongation and conduction delay (399 overdose-related co-reports, with a QT signal of 24 co-reports, PRR 2.4). Because tricyclics depress myocardial conduction, they are contraindicated after recent myocardial infarction and in significant conduction defects.
Regulatory basis: nortriptyline prescribing information — cardiac conduction effects; tricyclic overdose literature.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Conduction effects within the therapeutic range |
| Strength | met | PRR 2.4, modest here |
| Consistency | met | Consistent across tricyclics |
| Specificity | partial | Shared across the class |
| Biological gradient | met | Worse at higher plasma levels |
| Plausibility | met | Sodium-channel and repolarisation effects |
| Coherence | met | Fits the pharmacology |
| Experiment | met | Overdose series quantify it |
| Analogy | met | Direct class analogy to amitriptyline |
This table is this page's own qualitative read of the literature cited above, not an automated or citation-gated assessment — see the note at the bottom of this page.
✗ No ClinicalTrials.gov results-posting trial in the top search hits for nortriptyline-hydrochloride captured qt prolongation as a tracked adverse event in a usable structure. Tricyclic trials did not report QT prolongation as a structured coded adverse event.