As of March 2010, it is still available in the United Kingdom under the brand name Palladone SR, Nepal under the brand name Opidol, and in most other European countries. Pharmacokinetics
The chemical modification of the morphine molecule to hydromorphone results in higher lipid solubility and greater ability to cross the blood–brain barrier to produce more rapid and complete central nervous system penetration. On a per milligram basis, hydromorphone is considered to be five times as potent as morphine; although the conversion ratio may vary from 4–8 times, five times is in typical clinical usage. The development of tolerance also may vary among individuals. Patients with renal abnormalities must exercise caution when dosing hydromorphone. In those with renal impairment, the half-life of hydromorphone may increase to as much as 40 hours. The typical half-life of intravenous hydromorphone is 2.3 hours. Peak plasma levels usually occur between 30 and 60 minutes after oral dosing.The onset of action for hydromorphone administered intravenously is less than 5 minutes and within 30 minutes of oral administration (immediate release). Metabolism
While other opioids in its class, such as codeine or oxycodone, are metabolized via CYP450 enzymes, hydromorphone is not. Hydromorphone is extensively metabolized in the liver to hydromorphone-3-glucoronide, which has no analgesic effects. As similarly seen with the morphine metabolite, morphine-3-glucoronide, a build-up in levels of hydromorphone-3-glucoronide may produce excitatory neurotoxic effects such as restlessness, myoclonus and hyperalgesia. Patients with compromised kidney function and older patients are at higher risk for metabolite accumulation.
Aldurazyme is administered as a slow intravenous infusion. The recombinant enzyme is 628 amino acids in length with 6 N-linked oligosaccharide modification sites and two oligosaccharide chains terminating in mannose sugars. Medical use
Aldurazyme is indicated in the US for people with Hurler and Hurler-Scheie forms of Mucopolysaccharidosis I (MPS I) and for people with the Scheie form who have moderate to severe symptoms.Aldurazyme is indicated in the EU for long-term enzyme replacement therapy in patients with a confirmed diagnosis of mucopolysaccharidosis I (MPS I; alpha-L-iduronidase deficiency) to treat the nonneurological manifestations of the disease.Aldurazyme was approved for medical use in the United States and in the European Union in 2003. Pre-clinical work
Dosing for human clinical studies was based on canine MPS I studies. Clinical trials
Three clinical trials were performed to establish the pharmacology, efficacy, and safety of weekly intravenous administration of the drug. These studies included a Phase I open-label study, a Phase III randomized, double-blind, placebo-controlled study, and a Phase III open-label extension study. A Phase II Young Pediatric study was also conducted.Clinical trials and post-market safety data indicate that the most common adverse side effect of Aldurazyme is allergic reaction. In order to prevent allergic reaction and respiratory distress, the packet insert of Aldurazyme suggests that patients be administered antihistamines before infusion. Allergic reaction occurs in approximately 1% of patients. It is recommended that patients who are high-risk for respiratory distress be given their infusion in a facility equipped to deal with an anaphylactic response.