Knowledge
Collections with the topic tag Opioid
Addiction
Analgesia
Buprenorphine
Drugs
Fentanyl
Intrathecal
Meperidine
Morphine
Obstetric anesthesia
Oxycodone
Perioperative medicine
Remifentanil
Sufentanil
Tapentadol
Tramadol
-
-
-
-
Oxycodone is a semi-synthetic opioid commonly used as an oral, rectal or intravenous analgesic (subcutaneous, intramuscular & intranasal also possible). Trade names include Endone™, OxyContin™ and OxyNorm™.
A. Physiochemistry
- Semi-synthetic opioid; thebaine derivative. First synthesised in 1916.
B. Pharmacokinetics
- Dose
- Oxycodone po conversion from morphine IV 2:1 (oxycodone:morph).
- (NB: oral to IV morphine 3:1)
- 10 mg of oral oxycodone is equivalent to 20 mg of oral morphine.
- 10 mg of oral oxycodone is equivalent to 5 mg of IV/IM morphine.
- 10-15 mg of parenteral oxycodone (IV/IM) is equivalent to 10-15 mg parenteral morphine (ie. morphine up to 50% more potent)
- Absorption - orally up to 87%
- Distribution - 2.6 L/kg
- Protein binding
- Onset - within 10-15 min orally, peak 45-60 minutes; Offset ~2-3h.
- Metabolism - ß1/2 ~3-4hrs, metabolised principally to noroxycodone, noroxymorphone and oxymorphone (p450 system). Oxymorphone has some activity
- Clearance - 0.8 L/min; predominately renally excreted.
C. Pharmacodynamics
- Oxycodone is a full opioid agonist with no antagonist properties whose principal therapeutic action is analgesia.
- It has affinity for kappa, mu and delta opiate receptors in the brain and spinal cord.
- Oxycodone is similar to morphine in its action. Other pharmacological actions of oxycodone are in the central nervous system (respiratory depression, antitussive, anxiolytic, sedative and miosis), smooth muscle (constipation, reduction in gastric, biliary and pancreatic secretions, spasm of sphincter of Oddi and transient elevations in serum amylase) and cardiovascular system (release of histamine and/or peripheral vasodilation, possibly causing pruritus, flushing, red eyes, sweating and/or orthostatic hypotension).
- Strong potentially for tolerance, dependence and abuse.
-
A. Physiochemistry
- Semi-synthetic thebaine derivative (like oxycodone).
- Partial µ-agonist.
B. Pharmacokinetics
- Dose: 0.5 mg q6h IV/IM
- 30x morphine potency
- 200mcg-400mcg sublingual qid for analgesia
- Absorption - IV, IM, s/l, epidural (po undesirable as ++ 1st pass met)
- Distribution - 3 L/kg
- Protein binding - 96%
- Onset 30 min; Offset 4 h (longer latency & duration than morph)
- Metabolism - ß½ 5 h; hepatic dealkylation & glucuronidation. Excreted in bile & hydrolysed by GIT bacteria.
- Clearance - 14 mL/min/kg (dec 30% by GA)
C. Pharmacodynamics
- Mechanism: µ partial agonist.
- 50x greater mu rec affinity than morphine.
- May be used to treat heroin/morphine dependence.
- Greater lipid solubility than morphine.
- Ceiling effect to both analgesia & respiratory depression.
- Long duration as slow to dissociate from receptor & thus difficult to reverse.