Medetomidine, an alpha-2 adrenergic agonist originally developed for veterinary sedation, has moved into the unregulated drug supply faster than any new adulterant since xylazine. By the second half of 2024 it was routinely showing up in opioid samples in Philadelphia and parts of the Midwest. By late 2025 it was being detected in supplies from coast to coast. Programs added medetomidine test strips to their procurement lists. Most of those purchases happened before anyone knew the chemistry was complicated.
It is. In Harm Reduction Journal, January 2026, Andrea Amate and Marya Lieberman at the University of Notre Dame published "Chiral sensitivity of medetomidine lateral-flow immunoassay test strips" (HRJ 23:19, 2026), evaluating seven lots from two manufacturers. The result: medetomidine test strips fall into two distinct enantiomer-recognition profiles, and the difference can change a result from positive to negative on the same drug sample.
Two enantiomers, three behaviors
Medetomidine is a chiral molecule, which means it exists as two mirror-image forms (enantiomers): dexmedetomidine, which is the pharmacologically active form, and levomedetomidine, which is much less active. The veterinary product is sold as the racemic mixture (a 1:1 ratio of the two). Pharmaceutical-grade dexmedetomidine, used in human medicine for sedation, is sold as the single enantiomer.
The Amate and Lieberman paper categorized the seven evaluated lots into two types based on antibody binding behavior:
- Type 1 strips recognize dexmedetomidine specifically. They produce a positive result on racemic medetomidine at roughly twice the limit of detection observed for pure dexmedetomidine. They are negative on pure levomedetomidine.
- Type 2 strips require both enantiomers to produce a positive. They are negative on pure dexmedetomidine alone or pure levomedetomidine alone, and positive on the racemic mixture.
Both types catch the racemic form. Neither type is wrong, but the difference matters when a sample contains an unusual ratio of the two enantiomers, which is more common in the supply than most procurement officers realize.
What the supply actually contains
A companion analytical study by Sisco, Ventura, and Shuda, published in Drug Testing and Analysis in 2025 (doi:10.1002/dta.3947), characterized the enantiomeric ratio of medetomidine in 100 street drug samples collected between August 2024 and February 2025. The samples were predominantly racemic, consistent with sourcing from veterinary stocks. That is good news for both Type 1 and Type 2 strips: in the current supply, both will produce a positive on a real positive.
It is not, however, a permanent answer. If pharmaceutical-grade dexmedetomidine is diverted into the unregulated supply, Type 2 strips will read it as negative. If the synthetic source shifts to pure levomedetomidine (a possibility raised by both papers), Type 1 strips will miss it entirely. Either change is a one-batch event. A program standardized on a single strip type without understanding which type it is buying could find its detection rate drop sharply without any obvious cause.
The lab will eventually catch the gap. The strips will not. Enantiomer-aware procurement is the way to keep the strips honest.
How DSG validates the medetomidine line
DSG's medetomidine product line is validated against the racemic form, which matches what the field is currently encountering. The enantiomer-recognition profile of every lot is tracked and disclosed to buyers. No single lateral-flow strip detects every form of every alpha-2 agonist; specifications are documented accordingly rather than presented as a single binary.
Cross-reactivity with adjacent compounds is also tested. Detomidine, a related veterinary alpha-2 agonist, produces false positives on essentially all medetomidine strips at concentrations as low as 0.07 mg/mL on some lots, per the Amate and Lieberman data. Levamisole, an unrelated cutting agent commonly co-present in cocaine, produces faint lines on most lots that can be misinterpreted as a true positive. Xylazine does not cross-react. Each of these thresholds is documented for buyers so the field interpretation matches the data.
What this means for procurement
Three takeaways for any state, county, or harm-reduction program currently buying medetomidine strips:
- Ask the supplier which enantiomer profile their strip recognizes. Most cannot answer. The ones that can are demonstrating that they have read the literature.
- Do not standardize on a single brand permanently. The supply will shift. The strip that catches today's supply may miss tomorrow's. Build a procurement rhythm that allows lot-by-lot performance review, ideally using a community-published QA framework.
- Pair strips with confirmatory mass-spectrometry capacity at a partner lab where possible, especially as new analytes settle into the supply. Rapid strips are screening tools, not confirmatory diagnostics, and the medetomidine literature is candid about that.
Further reading
- Amate A, Lieberman M. (2026). Chiral sensitivity of medetomidine lateral-flow immunoassay test strips. Harm Reduction Journal 23:19. doi:10.1186/s12954-025-01387-6
- Sisco J, Ventura M, Shuda J. (2025). Enantiomeric determination of medetomidine in street drug samples (August 2024 to February 2025) and implications for immunoassay test strip analysis. Drug Testing and Analysis 17(12):2347-2353. doi:10.1002/dta.3947