Which of the following is a common prescription opioid?

Hydrocodone is a common prescription opioid widely used for its pain-relieving properties. It belongs to the class of drugs known as narcotics, which are effective in managing moderate to severe pain by acting on the opioid receptors in the brain. This action not only alleviates pain but can also produce feelings of euphoria, which can contribute to its potential for misuse and addiction.

In contrast, the other choices do not belong to the opioid category. Lithium is primarily used as a mood stabilizer in the treatment of bipolar disorder. Clonazepam is a benzodiazepine used to treat anxiety and seizure disorders, working as a central nervous system depressant. Atorvastatin is a statin medication used to lower cholesterol levels and reduce the risk of cardiovascular disease. Each of these medications serves distinctly different therapeutic purposes, which further reinforces why hydrocodone is the correct answer in identifying a common prescription opioid.