Phenobarbital is a Schedule IV controlled substance in a class of medications called barbiturates. It works by slowing activity on the brain to control seizures. Phenobarbital is also used to relieve anxiety. It is also used to prevent withdrawal symptoms in people who are dependent on another barbiturate medication and are going to stop taking the medication. Read more on drugs and their effects.
The drug testing kits below yield a positive result when Barbiturate metabolites in urine exceed 300 ng/mL. This is the suggested screening cut-off for positive specimens set by the Substance Abuse and Mental Health Services Administration (SAMHSA, USA).