I read on the DXM faq that DXM should not be combined with antihistamines. I'm using Opcon-A which says 'antihistamine' on the front, but its an eyedrop not a pill, will it affect me?

Also, why does the FAQ say this:
"SucretsTM (not the kind that come in the tin; these come in a bag and are labelled as containing DXM)."
I bought the kind in a plastic tin and all it says is "Medicinal ingredient: 15mg dextromethorphan hydrobromide"
moeburn Reviewed by moeburn on . DXM+eyedrops? I read on the DXM faq that DXM should not be combined with antihistamines. I'm using Opcon-A which says 'antihistamine' on the front, but its an eyedrop not a pill, will it affect me? Also, why does the FAQ say this: "SucretsTM (not the kind that come in the tin; these come in a bag and are labelled as containing DXM)." I bought the kind in a plastic tin and all it says is "Medicinal ingredient: 15mg dextromethorphan hydrobromide" Rating: 5