Different dosage forms of Phenobarbital have different specifications, generally there are three dosage forms: Phenobarbital tablets, Phenobarbital sodium for injection and Phenobarbital injection. 1. Phenobarbital tablets: the specifications are generally 15mg, 30mg and 100mg. 2. Phenobarbital sodium for injection: specifications are generally 50mg, 100mg, 200mg. 3. Phenobarbital injection: the specifications are usually 1ml: 100mg, 2ml: 200mg. Phenobarbital can be used to treat insomnia, anxiety, epilepsy and other diseases. It is prohibited for patients who are allergic to this drug and have a history of severe pulmonary insufficiency, cirrhosis of the liver, anemia, asthma, uncontrolled diabetes mellitus, and should be used with caution in patients with hypothyroidism, hypoadrenalism, low blood pressure, hypertension, and cardiac, hepatic, and renal impairments, as well as in women who are pregnant or breastfeeding. Adverse reactions such as memory or cognitive deficits, skin rash, and hypocalcemia may occur when taking this medication, and patients should use the medication under medical supervision.