I am asking about serious side effects... Both my husband and I suffered bouts of cough for 10 days. OTC we got Mucinex D (after using other cold relief, menthol etc for one week) and now we can't sleep if we take the evening dose. Seriously make mucomyst available to the general public because in only two remaining doses from a previous box bought overseas, we both are now clearing our trachea! So what is the matter behing mucomyst in the US?