Describe the pharmacology of oxycodone.
There were many exceptional answers which provided extensive detail on the drug. The best of these gave context for the drug characteristics, such as by referring to oxycodone relative to other opioid drugs that might be chosen, or to considerations for safe and effective administration. Some answers, however, provided generic information on opioid drugs, which could not gain all the available marks
|Routes of administration||Oral, IV|
|Absorption||Well absorbed orally, 80% bioavailability|
|Solubility||pKa 8.5, quite hydrophilic|
|Distribution||VOD = 2.6L/kg; 38–45% protein-bound|
|Target receptor||mu-opiate receptor (pre-synaptic G-protein coupled receptor)|
|Metabolism||Hepatic metabolism; notable metabolites include noroxycodone and oxymorphone, both active metabolites|
|Elimination||Minimal unchanged drug cleared renally, but most of the metabolites rely on renal excretion|
|Time course of action||Half-life 3-5 hours|
|Mechanism of action||Hyperpolarisation of cell membrane by increasing potassium conductance; reduced production of cAMP and closure of voltage-gated calcium channels|
|Clinical effects||Analgesia, respiratory depression, constipation, miosis, urinary retention.|
|Single best reference for further information||Crow et al (2021)|
Zöllner, C., and C. Stein. "Opioids." Handbook of Experimental Pharmacology (2006): 31-63.
Crow, Jessica R., Stephanie L. Davis, and Andrew S. Jarrell. "Pharmacology and Pharmacokinetics of Opioids in the ICU." Opioid Use in Critical Care. Springer, Cham, 2021. 31-64.
Cata, Juan P., and Shreyas P. Bhavsar. "Pharmacology of opioids." Basic Sciences in Anesthesia. Springer, Cham, 2018. 123-137.