Final answer:
Depression is a common adverse effect of opioid pain medications, such as codeine, morphine, and oxycodone. These medications can depress the central nervous system and disrupt the balance of chemicals that regulate mood.
Step-by-step explanation:
The nurse should instruct the client that depression is a common adverse effect of Opioid pain medications. Opioid pain medications, such as codeine, morphine, and oxycodone, can depress the central nervous system, leading to symptoms of depression. These medications can affect the brain's neurotransmitters and disrupt the balance of chemicals that regulate mood.