Monitoring amobarbital therapy
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Amobarbital is an intermediate-acting barbiturate with hypnotic properties used in short-term treatment of insomnia and to reduce anxiety and provide sedation preoperatively. (1, 2)
Amobarbital is administered by intravenous infusion or intramuscular injection. The duration of its hypnotic effect is about 6 to 8 hours. The drug distributes throughout the body, with a volume of distribution of 0.9 to 1.4 L/kg, and about 59% of a dose is bound to plasma proteins. Metabolism takes place in the liver primarily via hepatic microsomal enzymes. Its half-life is about 15 to 40 hours (mean: 25 hours). Excretion occurs mainly in the urine. (2, 3)
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Therapeutic concentration: 1.0-5.0 mcg/mL
Toxic concentration: >10.0 mcg/mL
Concentration at which toxicity occurs varies and should be interpreted in light of clinical situation.
The therapeutic range of amobarbital is 1 to 5 mcg/mL, with toxicity typically associated with concentrations >10 mcg/mL. (2)
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
The concentration at which toxicity occurs varies; results should be interpreted in light of the clinical situation.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Goodman & Gilman's: The Pharmacological Basis of Therapeutics. 10th edition. New York, McGraw-Hill Book Company, 2001
2. Teitz Textbook of Clinical Chemistry and Molecular Diagnostics. 4th edition. St. Louis, MO, Elsvier Saunders, 2006, pp 1091
3. Disposition of Toxic Drugs and Chemicals in Man. 7th edition. Edited by RC Baselt. Foster City, CA, Biomedical Publications, 2004, pp 1254