Promethazine (Phenergan) OTC and cheap 50-100mg depending on how strong you want to nod... (the base of lean, drank, sizzurp...)
Hydroxyzine (Atarax) Rx 25-150mg... less nod than promethazine but good potentiator also
White (i think?) grapefruite juice to favourise higheramount metabolism into morphine, i believe
stay safe, chip the codeine, try to not make it a habit bro...