Pharmacology Notes

Hydromorphone, a mu-opioid agonist, is available for oral, parenteral and intraspinal administration. It is structurally similar to morphine, but is 5 to 10 times more potent. Advantages include higher solubility, which enables administration of more concentrated solutions, and hence smaller volume requirements than morphine. Hydromorphone is metabolised to glucuronides, predominantly hydromorphone-3-glucuronide (H3G).

Psychotomimetic reactions can occur when hydromorphone is administered to patients with renal impairment, possibly due to the accumulation of H3G. Like morphine, hydromorphone is hydrophilic and has potential for adverse central nervous system effects after intrathecal administration, due to rostral spread to the brain in the CSF.