SPL Set ID: 9091250d-694a-4593-84dc-6fe54aef495f

The barbiturates are nonselective central nervous system (CNS) depressants which are primarily used as sedative hypnotics and also anticonvulsants in subhypnotic doses. The barbiturates and their sodium salts are subject to control under the Federal Controlled Substances Act (CIV). Barbiturates are substituted pyrimidine derivatives in which the basic structure common to these drugs is barbituric acid, a substance which has no central nervous system activity. CNS activity is obtained by substituting alkyl, alkenyl or aryl groups on the pyrimidine ring. Phenobarbital Sodium Injection, USP is a sterile solution for intramuscular or slow intravenous administration as a long-acting barbiturate. Each mL contains phenobarbital sodium either 65 mg or 130 mg, alcohol 0.1 mL, propylene glycol 0.678 mL and benzyl alcohol 0.015 mL in Water for Injection; hydrochloric acid added, if needed, for pH adjustment. The pH range is 9.2-10.2. Chemically, phenobarbital sodium is 2,4,6(1 H ,3 H ,5 H )-Pyrimidinetrione,5-ethyl-5-phenyl-, monosodium salt and has the following structural formula: C12 H 11 N 2 NaO 3 MW 254.22 The sodium salt of phenobarbital occurs as a white, slightly bitter powder, crystalline granules or flaky crystals; it is soluble in alcohol and practically insoluble in ether or chloroform. Chemical Structure