Lack of cross-reactivity of Ambien (zolpidem) with drugs in standard urine drug screens.

OBJECTIVE

To determine in healthy volunteers (men and women; 18 to 40 years old) the potential cross-reactivity of Ambien (zolpidem) and/or its metabolites with drugs that are screened by the Syva EMIT II and the Abbott ADx urine drug screens assays.

DESIGN

Open-label, fixed-treatment sequence of 1 night each of treatment with zolpidem (10 mg) and temazepam (15 mg).

SETTING

Clinical Pharmacology Unit within a teaching hospital.

MAIN OUTCOME MEASURES: Over a 24-hour period, presence or absence of positive results on the Syva EMIT II or the Abbott ADx urine drug assay system, each performed at two different laboratory assay sites.

RESULTS

Following ingestion of zolpidem, no subject had any positive response in either laboratory to the Syva EMIT II or the Abbott ADx urine drug screen assays at 0, 4, 8, 12, and 24 hours postdose. During the same time period, all subjects had measurable zolpidem plasma concentrations at 1.5 and 8 hours postdose, with mean concentrations of 115.2 ng/mL and 30.1 ng/mL, respectively (in agreement with its half-life of 2.5 hours). The positive response rate at 10 hours after ingestion of Restoril (temazepam) among the four laboratory/assay combinations ranged from 36.8% to 73.7%, a range that is within the reported response rates for these tests.

CONCLUSIONS

These data indicate that zolpidem will not cross-react in standard urine drug screens with benzodiazepines, opiates, barbiturates, cocaine, cannabinoids, or amphetamines.