Naloxone
Pure MOP antagonist used for:
- Treatment of opioid overdose
- Reducing constipation
In combination with PO oxycodone.
| Property | Drug |
|---|---|
| Class | μ-selective opioid receptor competitive antagonist |
| Uses | Opioid overdose, neuraxial opioid side effects (e.g. pruritus), prevention of constipation in combination with oral opioids |
| Presentation | Clear, colourless solution at 400mcg.ml-1 |
| Route of Administration | IV, IM, PO |
| Dosing | 0.1-0.4mg Q5min, 0.5mg.kg-1.hr-1 by infusion |
| Absorption | Very high first pass metabolism leading to ~2% PO bioavailability |
| Distribution | 50% protein bound. VD 2L.kg-1, highly lipid soluble. |
| Metabolism | Rapid hepatic glucuronidation |
| Elimination | Renal elimination |
| Resp | Reversal of opioid-induced respiratory depression (↑ RR, ↑ VT) |
| CVS | ↑ SVR & ↑ BP, arrhythmia due ↑ in SNS tone |
| CNS | ↓ Analgesia, ↓ sedation, ↓ miosis. Antanalgesic in opioid naive patients. Precipitation of opioid withdrawal. |
| Other considerations | Duration of action is ~30-40 minutes is shorter than some opioids, which may lead to re-narcosis if not given subsequent doses or by infusion |
References
- Peck TE, Hill SA. Pharmacology for Anaesthesia and Intensive Care. 4th Ed. Cambridge University Press. 2014.
- Smith S, Scarth E, Sasada M. Drugs in Anaesthesia and Intensive Care. 4th Ed. Oxford University Press. 2011.