If i am allergic to codeine and sulfa can i take clonazepam ?

Possilby: There is no cross-reactivity between these medications in terms of allergy. But Codeine and clonazapam both have sedating qualities and if taken at the same time, could be additive in their effects.

Usually none : Most Codeine reactions are not true allergies (symptoms are the same though since they are mediated by mast cells) and sulfa antibiotic reactions are specific to that class of medicine. There is no direct cross-reactivity between those medicines and Clonazepam however, since you have multiple adverse reactions to medications you are at a slightly higher risk of having a reaction to any new med.