FDA pharmacologic class
Opioid antagonists
7 medicines are in FDA's class of opioid antagonists (opioid antagonists): naloxone (Narcan), naltrexone (Vivitrol), nalmefene (Opvee), alvimopan, methylnaltrexone (Relistor), naloxegol (Movantik) and naldemedine (Symproic); 4 combination products also contain one. 6 of the 11 are listed from generic labelers (FDA NDC Directory, October 8, 2026). The lowest pharmacy cost is buprenorphine-naloxone 2-0.5 mg sl tablet at $0.521 per tablet (NADAC).
Which medicines are opioid antagonists?
| Medicine | Brand names | Generic labelers (all forms) | Pharmacy cost | Boxed warning | Shortage | Recalls since 2012 |
|---|---|---|---|---|---|---|
| Buprenorphine and naloxone | Zubsolv, Suboxone | 26 labelers | $0.521 per tablet 2-0.5 mg sl tablet | No | No current entry | 2 |
| Naloxone | Narcan, Rivive, Rextovy | 41 labelers | $12.74 per mL 2 mg/2 mL syringe | No | No current entry | 2 |
| Naltrexone | Vivitrol | 21 labelers | $1.14 per tablet 50 mg tablet | No | No current entry | 5 |
| Nalmefene | Opvee, Zurnai | 2 labelers | $46.79 per unit 2.7 mg nasal spray | No | No current entry | 0 |
| Alvimopan | none listed | 4 labelers | n/a | Yes | No current entry | 0 |
| Olanzapine and samidorphan l-malate | Lybalvi | none listed | $55.10 per tablet 10-10 mg tablet | Yes | No current entry | 0 |
| Methylnaltrexone | Relistor | none listed | n/a | No | No current entry | 0 |
| Naloxegol | Movantik | none listed | $14.61 per tablet 25 mg tablet | No | No current entry | 0 |
| Naloxone and pentazocine | none listed | 3 labelers | $2.06 per tablet Pentazocine-naloxone tablet | Yes | No current entry | 0 |
| Bupropion and naltrexone | Contrave | none listed | n/a | Yes | No current entry | 2 |
| Naldemedine | Symproic | none listed | $16.26 per tablet 0.2 mg tablet | No | No current entry | 1 |
Source: FDA Established Pharmacologic Class (NDC Directory, openFDA); CMS NADAC of October 7, 2026; FDA shortages and recalls (FDA files October 8, 2026)
What do pharmacies pay?
Each medicine's most widely listed form, per unit, in the NADAC survey: what pharmacies paid, not what a patient pays; strengths differ, so compare like with like.
Source: CMS National Average Drug Acquisition Cost (NADAC) survey, October 7, 2026: what retail pharmacies paid per unit; not a counter price