BUTAS - Clinical: Butalbital, Serum

Test Catalog

Test Name

Test ID: BUTAS    
Butalbital, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Monitoring butalbital therapy

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Butalbital is a short-acting barbiturate with hypnotic properties that is used in combination with other drugs such as acetaminophen, salicylate, caffeine, and codeine.(1)


Butalbital is administered orally. The duration of its hypnotic effect is about 3 to 4 hours. The drug distributes throughout the body, with a volume of distribution (Vd) of 0.8 L/kg, and about 26% of a dose is bound to plasma proteins. Butalbital's half-life is about 35 to 88 hours. Excretion occurs mainly in the urine.(1,2)

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.

<10 mcg/mL

Interpretation Provides information to assist in interpretation of the test results

Butalbital concentrations of 10 mcg/mL or greater have been associated with toxicity.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

No significant cautionary statements

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Disposition of Toxic Drugs and Chemicals in Man. Seventh edition. Edited by RC Baselt. Foster City, CA, Biomedical Publications, 2004, p 1254

2. Teitz Textbook of Clinical Chemistry and Molecular Diagnostics. Fourth edition. Edited by CA Burtis, ER Ashwood, DE Bruns. St. Louis, MO, Elsevier