I will be soon starting on treatment with low dose naltrexone at 4.5 mg for my fibro and chronic pain and to build up my immune system which my chemo is destroying. Dexomothorphan and codeine both interefer with the naltrexone so am searching for something I can take with my chronic coughs from upper respiratory infections so I can get some sleep. ## Hello, Sue! How are you? I'm sorry about the health problems you've been having. I couldn't find anything listed under the name Tussent. Can you please double check the name/spelling and post back? Is this something that was prescribed, or is it available over the counter? Naltrexone is listed by the FDA as being an opioid receptor agonist and its most common side effects may possibly include nausea, dizziness, diarrhea and abdo...