Alka-Seltzer Plus Severe Cold & Flu contains:

- Acetaminophen
- Chlorpheniramine
- Dextromethorphan
- Phenylephrine

Is this the same medication you're asking about? They make a number of different formulations. If the active ingredients listed on the box are different form the ones above please let me know.

Next, I used the drug interaction checker on WebMD against Amoxicillin and there were no interactions found.

I would still recommend checking with your pharmacist just to make sure the cold medication will not reduce the efficacy of your antibiotics. I hope this helps and feel better!