Some street names for phenobarbital include purple hearts and goof balls, according to eMedicineHealth. Phenobarbital is a barbiturate drug that depresses the activity of the nervous system and brain. Addiction from barbiturate use can occur in as little as a month, and the symptoms of withdrawal are often life-threatening.
Doctors prescribe phenobarbital to control seizures, relieve anxiety and prevent symptoms of withdrawal in people who are dependent on other barbiturate medications, notes MedlinePlus. It is available in both liquid and tablet formulas, usually designed to be taken one to three times daily. As is the case with other barbiturates, phenobarbital can cause dependence in users.