Description of Dilaudid
Hydromorphone is a pure opioid, a semi-synthetic hydrogenated ketone derivative of Morphine that has been available clinically since 1920. Structurally, hydromorphone derived from Morphine in the modification of the hydroxyl group in the carbon 6 to a carbonyl and the absence of a double bond between the carbon 7 and 8.
Due to these modifications, it presents a very high potency and comparable side effect profile to the parent compound.Even though hydromorphone does not present a 6-hydroxyl group, it is categorized under the family of phenanthrenes and it is considered a chemical under the schedule II.
The first reported approved product containing hydromorphone in the form of hydromorphone hydrochloride was developed by Fresenius Kabi USA and FDA approved in 1984.
Absorption of Dilaudid
The immediate release version of hydromorphone reaches its peak concentration after 30-60 minutes while the extended-release version reaches the peak concentration after 9 hours. When administered orally, hydromorphone is absorbed mainly in the upper small intestine with a bioavailability of 60% due to intensive first-pass metabolism.
In the controlled-release version of hydromorphone, the absorption follows a biphasic pharmacokinetic profile. However, even though there are clear distinctions in the absorption pathway of hydromorphone, the AUC of both versions is reported to be of 34 ng.h/ml which indicates an equivalence.
Metabolism of Dilaudid
The metabolism of hydromorphone is mainly hepatic and it is mainly represented by the generation of hydromorphone-3-glucuronide through glucuronidation reactions. This primary metabolic pathway is done by the activity of the UDP-glucuronosyltransferase-2B7. The first-pass hepatic metabolism is so large that it represents 62% of the initial administered dose.
On the other hand, hydromorphone is also characterized by the presence of minor metabolic pathways such as the CYP3A4- and CYP2C9-driven generation of norhydromorphone.