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Paediatric Laboratory Medicine

Barbiturates and Sedatives (B)

Clinical Significance

The Barbiturates are a large group of structurally similar sedative-hypnotic drugs which are subject to abuse. Screening assays such as this are used to establish the presence or absence of the drug class based on a pre-determined threshold value. Alternative methods must be employed to determine the identity and concentration of any barbiturate from a positive screening result. Barbiturates are grouped into short-acting and long-acting as follows:

  • Ultra-short acting: Thiopental
  • Short acting: Pentobarbital, Secobarbital
  • Intermediate acting: Amobarbital, Butabarbital, Butalbital 
  • Long acting: Phenobarbital, Barbital

The Sedative-hypnotics are a large group of drugs which cause CNS depression. Most stimulate the activity of Gamma Aminobutyrate (GABA), the principle inhibitory neurotransmitter in the CNS. 

Similar to the barbiturates the sedatives can be grouped into short-acting and long-acting as follows:

  • Short acting: Methyprylon 
  • Intermediate acting: Glutethimide, Meprobamate, Methaqualone

 Many of the symptoms seen with barbiturate toxicity are also observed with the sedative-hypnotics. These include: lethargy, coma, hypothermia, slurred speech, irritability, respiratory depression and cardiovascular complications.

Test Name

Barbiturates and Sedatives (B)

Alternate Name/ Synonym

Amobarbital, Barbital, Butabarbital, Butalbital, Pentobarbital, Pentobarbital, Secobarbital, Glutethimide, Meprobamate, Mathaqualone, Methyprylon

Test Code


Drug Class

Barbiturates and Sedatives Screen





External Proficiency Testing


Turn Around Time

Daily, Stat

Specimen Type

Serum, Plasma (Heparin, Citrate or EDTA)

Minimum Specimen Requirements

1.0 mL


4° C (transport with a cool pack if possible)

Approval is not required

CPT Codes


Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Phone: 416-813-7200
Phone: 1-855-381-3212

Therapeutic Range

Not detected

Critical Values