Which of the following is a commonly used opioid analgesic for parenteral administration?

Morphine is widely recognized as a commonly used opioid analgesic for parenteral administration due to its effectiveness in managing moderate to severe pain. It is often administered through injection (intravenous, subcutaneous, or intramuscular) in settings such as hospitals or hospice care, where rapid onset of pain relief is essential for patient comfort.

Morphine provides a reliable analgesic effect, which is particularly important in palliative care settings, where patients may be experiencing significant pain and require immediate relief. Its pharmacokinetic profile allows for various dosing methods, and it can be titrated to suit the needs of individual patients.

Other options, while they play important roles in pain management, are either not typically administered parenterally or are more commonly utilized in oral formulations. For example, oxycodone and hydrocodone are primarily prescribed in oral forms, and while they can be used in some specialized circumstances, they are not standard for parenteral use. Codeine, too, is largely available in oral formulations and lacks the immediate action and potency of morphine when given by injection, which makes morphine the preferred choice in clinically urgent scenarios for effective pain control.