Clinical pharmacokinetics of lorazepam: a review
Kyriakopoulos, A.A.; Greenblatt, D.J.; Shader, R.I.
Journal of Clinical Psychiatry 39(10 Part 2): 16-23
1978
ISSN/ISBN: 0160-6689 PMID: 30762 Document Number: 137480
The clinical pharmacokinetics of lorazepam, a 3-hydroxy, 1,4-benzodiazepine, indicate that it is rapidly and readily absorbed, reaching peak concentrations in the blood proportional to the dose approximately 2 hours after oral administration. Blood levels decline thereafter, with an elimination half-life of about 12 hrs. Conjugation with glucuronic acid to form inactive lorazepam glucuronide is the major metabolic pathway. Seventy (70) to 75% of the administered dose is excreted as the glucuronide conjugate in the urine. On multiple-dose regimens, steady state blood levels directly proportional to the daily dose occur within 2--3 days and are maintained after several months of continuous treatment. The active drug and the glucuronide conjugate are completely eliminated from the blood within 1 week following the last dose.