Can you take focalin with robitussin cough syrup?

Well that is a very difficult question to answer, it really just depends on the medications within the cough syrup. You should be able to find a list of active ingredients on the bottle. Here is a link where you can find all the drug interactions with Ritalin. There are 400 drugs that interact with Ritalin, simply search if the ingriediants of your cough syrup interact with Ritalin.

http://www.drugs.com/drug-interactions/methylphenidate,ritalin.html