Dilaudid 4mg is a prescription opioid medication used to manage moderate to moderately severe pain. It works by binding to opioid receptors in the brain, altering the perception of pain, and inhibiting the reuptake of serotonin and norepinephrine, which also contribute to its analgesic effects. Dilaudid 4mg is available in immediate-release and extended-release formulations. While considered less potent than other opioids, it still carries risks of dependence, addiction, and respiratory depression, especially when misused or taken in high doses. Common side effects may include nausea, dizziness, constipation, and drowsiness.