Dose Heterogeneity
Definition
The variation in active ingredient content between nominally identical tablets in a counterfeit or clandestinely pressed batch. High dose heterogeneity in illicit fentanyl tablets is a primary driver of overdose deaths when a high-dose tablet is consumed without warning.
- Applies to
- Counterfeit and clandestinely pressed tablets
- Measures
- Variation in active ingredient content between tablets
- Major driver of
- Overdose deaths from illicit fentanyl
- Cause
- Uneven mixing during illicit pill pressing
Common questions
How do forensic labs quantify dose heterogeneity in a seized batch?+
Analysts assay individual tablets from a batch, typically using chromatographic methods, and compare the active ingredient mass across a sample of pills rather than testing one pill and assuming uniformity. A wide spread in results across nominally identical tablets is reported as high heterogeneity.
Why is dose heterogeneity more dangerous with fentanyl than with older street drugs?+
Fentanyl is active in microgram quantities, so even a small absolute variation in mixing can produce a tablet many times more potent than its neighbours. Because the visual dose is identical, a user has no way to detect a hot spot before taking it, unlike drugs with wider therapeutic margins.
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