- Naltrexone, acamprosate, alcohol dehydrogenase inhibitors, topiramate, gabapentin, ondansetron, benzodiazepines, beta-blockers, H2-blockers, and alpha-1 blockers, baclofen, and barbiturates as well as hormone replacement therapy; medications and dietary/herbal supplements (like St. John's wort) that interact with Cytochrome P450 3A4. All of the medications in the previous sentence will not be allowed if they have been taken within 2 weeks of study medication administration.