Butalbital and driving impairment

J Forensic Sci. 2013 Jul;58(4):941-5. doi: 10.1111/1556-4029.12143. Epub 2013 May 17.


Butalbital (Fiorinal(®)), used in the treatment of migraines and muscle pain, is the most commonly encountered barbiturate in impaired driving cases. It has central nervous system (CNS) depressant properties, including sedation, drowsiness, and feelings of intoxication, which can contribute to driving impairment. Twenty-six driving under the influence cases are reviewed including results from field sobriety tests and toxicology testing. Blood samples were screened using enzyme multiplied immunoassay technique immunoassay, and the presence of butalbital was confirmed and quantified using gas chromatography/mass spectrometry, gas chromatography with flame ionization detection, or gas chromatography nitrogen/phosphorus detection. Butalbital concentrations ranged from 1.0 to 30.2 mg/L, with a mean and median of 16.0 mg/L. General impairment indicators in these cases included horizontal and vertical nystagmus, lack of convergence, poor motor coordination, and balance and speech problems, which are common to CNS depressant intoxication, similar to that associated with alcohol. These findings indicate the importance of toxicological testing for butalbital in cases where CNS depressants are indicated.

Keywords: barbiturates; butalbital; driving impairment; forensic science; nystagmus; toxicology.

MeSH terms

  • Adult
  • Ataxia / chemically induced
  • Automobile Driving / legislation & jurisprudence*
  • Barbiturates / adverse effects*
  • Barbiturates / blood
  • Female
  • Forensic Toxicology
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Immunoassay
  • Law Enforcement
  • Male
  • Middle Aged
  • Nystagmus, Pathologic / chemically induced
  • Postural Balance / drug effects
  • Speech Disorders / chemically induced


  • Barbiturates
  • butalbital