Do nyquil and antiviral drugs have a dangerous interaction?

Should be OK. Should be ok when used as directed. Always a good idea to notify your doctor or pharmacist when using over the counter products.
NyQuil . I try not to throw the kitchen sink at a cold. With all of the medications that are in nyquil, i would rather take an appropriate medication for my symptom. Pain, pain reliever. Cough, cough suppressant , etc. That being said, there are many antiviral drugs. I checked Acyclovir and it was ok to use with nyquil.