- A benzomorphan drug
- Acts as a partial KOP and DOP agonist and a MOP antagonist
- This is beneficial as it causes analgesia with little respiratory depression
- However, use is limited by pronounced side-effects including nausea & vomiting, dysphoria and hallucinations
Partial Opioid Agonists and Mixed Agonist/Antagonist Drugs
Partial Opioid Agonists and Mixed Agonist/Antagonist Drugs
- A semi-synthetic phenanthrene derivative
- Presents as a clear, colourless solution of 10mg/ml nalbuphine for IV/IM/SC injection
- Acts as a:
- Partial KOP receptor agonist
- MOP antagonist
Pharmacodynamics
- Respiratory
- Does not cause respiratory depression
- However, it doesn't obtund airway reflexes to laryngoscopy
- Neurological
- Causes analgesia via KOP agonism
- Does not cause dependence (μ-receptor antagonism) but will precipitate withdrawal symptoms in those with opioid dependence
- Sedation, dizziness, vertigo, dry mouth, headache
- It is equipotent to morphine but there is a ceiling effect with respect to respiratory depression and analgesic actions
- Is a full KOP agonist and MOP antagonist
- A long-acting competitive opioid antagonist with a duration of action of 48-72hrs
- Primarily used in patients who are highly motivated to remain abstinent from alcohol or a substance abuse disorder
- Chronic use results in increased sensitivity to morphine-induced analgesia and a doubling of CNS MOP and DOP receptors, which take 6 days to return to baseline
- Patients taking naltrexone are opioid-resistant while taking it but then opioid-sensitive once it has been stopped