Substance · depressant
Barbiturates
Barbiturates are an older class of CNS depressants. Their use in routine medicine is now limited, but they remain on 10-panel screens and many recovery-monitoring panels.
Last updated:What is Barbiturates?
A class of GABA-A receptor agonists used historically as sedatives and anticonvulsants and still occasionally prescribed (e.g., phenobarbital, butalbital combinations).
Panels that include Barbiturates
What drug tests detect
Drug tests for Barbiturates typically target the following analytes / metabolites:
- Hydroxylated and conjugated parent compounds
Confirmation testing uses GC-MS or LC-MS/MS.
Detection windows
| Specimen | Window | Pattern | Caveat |
|---|---|---|---|
| Urine | 1–7 days | occasional | Short-acting clears in days; phenobarbital can persist 2–3 weeks. |
| 7–21 days | chronic | Phenobarbital has a very long half-life (~80h). |
Ranges are approximate and vary by individual physiology, hydration, dose, frequency of use, and lab cutoff. They are not predictive of whether someone will "pass" a test.
Cross-reactivity and MRO interpretation
The following can affect initial immunoassay screening and are normally resolved by mass-spectrometry confirmation and MRO review. None of these are a reason to draw conclusions from a single screening result.
- Theophylline (historical)
Sources & references
drugtest.co content is sourced from primary regulatory and clinical references. We do not cite gray-market or "how to pass" sources.