Hydromorphone is a derivative of morphine; to be specific, a hydrogenated ketone thereof, and it can be said that hydromorphone is to morphine as hydrocodone is to codeine and, therefore, a semi-synthetic drug. It is in medical terms an opioid analgesic and in legal terms a narcotic. Hydromorphone is commonly used in the hospital setting, mostly intravenously (IV) because its bioavailability orally, rectally, and intranasally is very low. Sublingual administration is usually superior to swallowing for bioavailability and effects. Hydromorphone is much more soluble in water than morphine and therefore hydromorphone solutions can be produced to deliver the drug in a smaller volume of water. Hydromorphone, a semi-synthetic μ-opioid agonist, is a hydrogenated ketone of morphine and shares the pharmacologic properties typical of opioid analgesics.