Benzodiazepines vary enormously in detection time because different compounds have vastly different half-lives. Short-acting benzos like alprazolam (Xanax, half-life 6–12h) clear much faster than long-acting compounds like diazepam (Valium, half-life 20–100h with active metabolites). This calculator provides detection estimates based on general benzodiazepine pharmacokinetics.
Diazepam produces nordiazepam (active metabolite, half-life 40–100 hours), which can extend detection for weeks after a single dose of the parent compound. This is why some benzodiazepines are detectable long after effects have worn off.
CRITICAL SAFETY: Benzodiazepine withdrawal after regular use can cause seizures and be life-threatening. Physical dependence can develop within 2–4 weeks of daily use. Never stop benzodiazepines abruptly — medical supervision is essential for tapering.
Standard immunoassay drug panels test for benzodiazepines as a class. However, some newer designer benzodiazepines may not cross-react with standard assays. Confirmation testing via LC-MS/MS can identify specific compounds.
Benzodiazepine Clearance
Clearance = 5 × Half-life (varies by compound: 6h for alprazolam to 100+h for diazepam metabolites)
Short-acting (alprazolam, lorazepam): cleared in 1–3 days. Long-acting (diazepam, clonazepam): cleared in 5–14+ days. Active metabolites extend the window significantly.
Occasional diazepam (Valium) use, tested 7 days later.
Result: Diazepam with its long-acting metabolite can be detected in urine for 2–4 weeks after occasional use. Short-acting benzos (Xanax) clear in 3–5 days.
Alprazolam (Xanax): 2–4 days for occasional use, up to 7 days for chronic use. It's a short-acting benzo with no significant active metabolites.
Diazepam (Valium): 7–21+ days due to its active metabolite nordiazepam (half-life 40–100 hours). Even a single dose can be detectable for over a week.
NO — abrupt benzodiazepine cessation after regular use can cause seizures and be fatal. Always taper under medical supervision. This is a medical emergency risk.