Search
Naltrexone and methylnaltrexone are both mu-receptor antagonists that look similar and have similar names. But, they have very different uses.
- Naltrexone (ReVia, Vivitrol)
- Used to treat opioid/alcohol dependence or to prevent relapse following opioid detoxifcation
- Dose: 25 to 100 mg PO daily or 380 IM every 4 weeks
- Crosses blood-brain-barrier and can precipitate withdrawal
- Methylnaltrexone (Relistor)
- Used to treat opioid-induced constipation
- Dose (weight-based): 8 to 12 mg (or 0.15 mg/kg) subcutaneously once daily
- Peripherally acting, does not cross blood brain barrier
References
Follow me on Twitter (@pharmERtoxguy).