Test directory: Clobazam and Metabolite

Ordering Code 7879
Test Name Clobazam and Metabolite
Alias Clobazam and Metabolite, Serum/Plasma
Frisium
Onfi
Sympazan
Urbanyl
Desmethylclobazam
Preferred Specimen Plasma
Preferred Container EDTA, K2 (Lavender)
Other Specimen/Container Serum in Plain (Red)
Optimum Volume 1 mL
Handling Instructions Promptly centrifuge and separate Serum or Plasma
Transport Requirements Oahu: Ambient
Airline: Ambient
Specimen Stability Ambient: 14 Days
Refrigerated: 30 Days
Frozen: 2 Months
Rejection Criteria Gel barrier tube
Avail. Stat NO
Analytic Time 10 Days
Methodology High Performance Liquid Chromatography/Tandem Mass
Spectrometry (LC-MS/MS)
Reference Lab  National Medical Services, Inc.

Reference range(s)

The reference ranges listed below are valid on this date of June 29, 2025.
Component Age Male Norm Male Critical Low Male Critical High Female Norm Female Critical High Female Critical Low Units Add'l info
Clobazam ALL ng/mL

Clobazam is a...
Clobazam is a benzodiazepine drug used as an anxiolytic and antiseizure medication. It is also employed as an adjunctive therapy for the treatment of seizures in patients with
Lennox-Gastaut syndrome. The average (range) peak plasma concentrations reported following a single 20 mg dose was 465 (222-709) ng/mL. Reported average steady-state plasma concentrations of 1076 ng/mL and 2884 ng/mL were reported following 40 mg/day and 160 mg/day doses, respectively. The mean concentrations of clobazam did not differ between CYP2C19 extensive and poor metabolizers. The recommended therapeutic range for clobazam is 30-300 ng/mL

See report.
Note1
Desmethylclobazam ALL ng/mL

N...
N-desmethlyclobazam is the primary pharmacologically active metabolite of Clobazam, a benzodiazepine drug used as an anxiolytic and antiseizure medication. The average (range) peak plasma concentrations reported following a single 20 mg dose was 88 (61-146) ng/mL. Reported average steady-state serum/plasma concentrations of 2783 ng/mL and 11020 ng/mL were reported following 40 mg/day and 160 mg/day doses, respectively. Excluding poor metabolizers decreased the mean
N-desmethylclobazam concentration. The N-desmethylclobazam/clobazam ratio has been reported to be 5 times higher in poor metabolizers than in extensive metabolizers. The recommended therapeutic range for
N-desmethylclobazam is 300-3000 ng/mL. Poor metabolizers or patients on CYP3A4 inducers and/or CYP2C19 inhibitors have been reported to have elevated concentrations of N-desmethylclobazam and increased adverse reactions

Analysis by High Performance Liquid Chromatography/Tandem Mass
Spectrometry (LC-MS/MS)
This test was developed and its performance characteristics determined by NMS Labs. It has not been cleared or approved by the US Food and
Drug Administration

See report.
Note2

Note1:


Clobazam is a benzodiazepine drug used as an anxiolytic and antiseizure medication. It is also employed as an adjunctive therapy for the treatment of seizures in patients with
Lennox-Gastaut syndrome. The average (range) peak plasma concentrations reported following a single 20 mg dose was 465 (222-709) ng/mL. Reported average steady-state plasma concentrations of 1076 ng/mL and 2884 ng/mL were reported following 40 mg/day and 160 mg/day doses, respectively. The mean concentrations of clobazam did not differ between CYP2C19 extensive and poor metabolizers. The recommended therapeutic range for clobazam is 30-300 ng/mL

See report..

Note2:


N-desmethlyclobazam is the primary pharmacologically active metabolite of Clobazam, a benzodiazepine drug used as an anxiolytic and antiseizure medication. The average (range) peak plasma concentrations reported following a single 20 mg dose was 88 (61-146) ng/mL. Reported average steady-state serum/plasma concentrations of 2783 ng/mL and 11020 ng/mL were reported following 40 mg/day and 160 mg/day doses, respectively. Excluding poor metabolizers decreased the mean
N-desmethylclobazam concentration. The N-desmethylclobazam/clobazam ratio has been reported to be 5 times higher in poor metabolizers than in extensive metabolizers. The recommended therapeutic range for
N-desmethylclobazam is 300-3000 ng/mL. Poor metabolizers or patients on CYP3A4 inducers and/or CYP2C19 inhibitors have been reported to have elevated concentrations of N-desmethylclobazam and increased adverse reactions

Analysis by High Performance Liquid Chromatography/Tandem Mass
Spectrometry (LC-MS/MS)
This test was developed and its performance characteristics determined by NMS Labs. It has not been cleared or approved by the US Food and
Drug Administration

See report..