Final answer:
They can be abused and are also found illegally on the streets, but they are not available over-the-counter due to their dangerous side effects and potential for overdose. Barbiturates are available with a prescription from a doctor, which is option (a).
Step-by-step explanation:
Barbiturates are central nervous system (CNS) depressants used in the medical field for various purposes, including as an anxiolytics, hypnotics, and anticonvulsants. Barbiturates are CNS depressants and are available by prescription for various medical purposes. These substances were initially developed to replace other sedatives like opiates and alcohol. Today, there are around 2,500 known derivatives of barbituric acid, but only about 15 of them are in medical use, such as phenobarbital and pentobarbital. The misuse of barbiturates, whether legal or illegal, can lead to serious overdose symptoms like incoordination, slowness of thought, drowsiness, and potentially death.
Barbiturates are available with a prescription from a doctor and are used in clear medical applications such as general anesthesia or the management of seizures. Despite their significant risks, they are still in use, albeit less frequently due to the development of safer alternatives like benzodiazepines and nonbenzodiazepines. Barbiturates can also be found on the streets as illegal drugs, and when combined with other substances like alcohol or benzodiazepines, the risk of overdose is especially heightened. However, they are not available over-the-counter due to the high risk associated with their use.