- Design
- Algorithm development and internal validation
- Population
- 69 literature-supported cascade pairs and 138 negative pairs
- Primary outcome
- Classification performance
- Effect
- Sensitivity 85.5%, specificity 99% or more, accuracy 94.7%
A development and internal validation study in Drug Safety (September 2026) describes an algorithm within the PINA medication-review tool that matches adverse reactions listed for one drug against the indications of another, using Italian summaries of product characteristics coded in MedDRA.
Against 69 literature-supported cascade pairs and 138 random negative pairs, specificity was 99% or more for every configuration. Sensitivity rose from 50.7% with narrow term matching to 85.5% when matching was broadened to higher-level terms and standardised queries, with accuracy of 94.7% and positive predictive value of 98.3%.
The reference set is small and artificially balanced, and the tool is not yet tested in real medication reviews. But the idea is practical: most prescribing cascades are recognisable pairs, and software can flag them for a clinician to judge.
- Look for classic cascades at every medication review: calcium channel blocker then diuretic for oedema
- Ask 'was this drug started to treat a side effect of another?' for each new prescription
- Check for cholinesterase inhibitor then anticholinergic for urinary symptoms
- Check for antipsychotic or metoclopramide then an antiparkinsonian drug
- Treat an algorithm flag as a prompt to review, not an instruction to stop
Why it matters
Prescribing cascades are a leading, preventable driver of polypharmacy, and are hard to see without a systematic check.
Don't overread it
Validation used a small, artificially balanced reference set; real-world performance in clinic is untested.
The statistics, in plain English
Sensitivity of 85.5% means the algorithm caught about 6 in 7 known cascade pairs; specificity of 99% means it rarely flagged unrelated pairs. Positive predictive value depends on how common cascades are, so it will be lower in real prescribing than in this 1:2 test set.
Read the rest in the app
You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.
Scan to keep reading on your phone. No account needed to start.
Tomorrow morning, before your first patient
One edition a day for clinical pharmacology, written by the desk, every claim tied to its paper. Six minutes.
Get the app — free