PHENobarbital

This test measures phenobarbital, a long-acting barbiturate medication used to treat seizures and manage certain neurological conditions. Testing is essential for therapeutic drug monitoring—ensuring levels stay within the effective range without causing toxicity. Phenobarbital accumulates in the body over time, requiring careful monitoring. Levels may be checked when starting therapy, adjusting doses, or investigating symptoms like excessive sedation. The medication is metabolized slowly, so testing helps prevent overdose and maintain seizure control.