Phenobarbital 100mg is a long-acting barbiturate that is commonly used in the treatment of epilepsy and seizure disorders. It works by depressing the activity of the central nervous system (CNS), which helps to reduce excessive electrical activity in the brain and prevent seizures. Phenobarbital is one of the oldest anticonvulsants available and is often prescribed for patients who do not respond to other treatments. In addition to its use in treating epilepsy, Phenobarbital is also used for sedation and to manage anxiety, although its primary use is in seizure control. The drug works by increasing the activity of a neurotransmitter called GABA, which inhibits brain activity, helping to prevent seizures. While effective, Phenobarbital can cause side effects such as drowsiness, dizziness, and confusion, especially when starting treatment or increasing the dose. Overuse or misuse of Phenobarbital can lead to tolerance and dependence, and it can also cause respiratory depression. It is important to follow dosing instructions closely to avoid serious side effects and withdrawal symptoms.