Final answer:
Opioids are the CNS depressant drugs that include adverse effects such as nausea, vomiting, constipation, and respiratory depression in the event of an overdose.
Step-by-step explanation:
Among the options provided, C) Opioids are the class of drugs classified as a CNS depressant that commonly have adverse effects including nausea, vomiting, constipation, and, in the event of an overdose, respiratory depression. The use of opioids can result in significant suppression of central nervous system activity. This can lead to pain relief and sedation, but also poses serious risks, including the potential for addiction and respiratory distress. Opioids work by binding to specific receptors in the brain, which in turn can affect the perception of pain as well as emotions.
Benzodiazepines and Barbiturates are also CNS depressants that work as GABA agonists and have a calming effect on the brain. They are used to treat anxiety, insomnia, and seizures, but they are not primarily associated with the adverse effects of nausea, vomiting, and constipation. On the other hand, Amphetamines are central nervous system stimulants and would not be expected to lead to the sedative effects associated with CNS depressants.