Phenobarbital (Gardinal)

Phenobarbital is a long‑acting barbiturate primarily used as an anticonvulsant: treating generalized and focal seizures, neonatal seizures, and as a second‑ or third‑line agent for status epilepticus. It’s also used for short‑term sedation, preoperative sedation, and sometimes to manage severe alcohol or benzodiazepine withdrawal. Because of side effects and interactions, its use is reserved when safer alternatives are unsuitable.

Phenobarbitone (Gardenal) is a long‑acting barbiturate mainly used as an anticonvulsant to prevent and control seizures — including generalized tonic‑clonic, focal epileptic seizures and neonatal seizures. It can be given intravenously as a second‑line agent in status epilepticus and is sometimes used for short‑term sedation. Due to side effects and dependence risk, it’s less commonly used for insomnia or chronic anxiety.

Phenobarbital was originally developed and introduced in 1912 as a sedative‑hypnotic to induce sleep and calm anxiety; soon after, its strong anticonvulsant properties were recognized and it became one of the first and most widely used treatments for epilepsy and seizure control. It was also used for sedation, preoperative anxiety, and sometimes to calm newborns or manage withdrawal symptoms.

No. Phenobarbitone (phenobarbital) and phenytoin are different antiepileptic drugs. Phenobarbital is a barbiturate that enhances GABAergic inhibition; phenytoin is a hydantoin that stabilizes neuronal sodium channels. Both treat seizures but differ in mechanism, side effects, interactions and dosing. They are not interchangeable without medical supervision.

Yes. Phenobarbital is considered a high‑risk medication. It has a narrow therapeutic window and can cause significant sedation, respiratory depression, tolerance, dependence and severe withdrawal. It interacts with many drugs, requires serum‑level monitoring and dose adjustments in liver disease, and poses special risks in neonates, the elderly and pregnancy. Careful prescribing and monitoring are essential to reduce harm.

Common side effects include dizziness, drowsiness/somnolence, fatigue, coordination problems/ataxia, tremor, blurred vision, and gastrointestinal symptoms (nausea, vomiting). Other effects: weight gain, peripheral edema, dry mouth, cognitive or memory impairment, mood changes and rare increased suicidal thoughts. Abrupt stopping can cause withdrawal; combining gabapentin with opioids or other depressants raises risk of severe sedation and respiratory depression. Consult your clinician for concerns.