These drugs may be given Orally (cromolyn, ketotifen) Intranasally (eg, azelastine, cromolyn) Ocularly (eg, azelastine, cromolyn, lodoxamide, ketotifen, nedocromil, olopatadine, pemirolast) Several ocular and intranasal drugs (eg, azelastine, ketotifen, olopatadine, pemirolast) are dual-acting mast cell stabilizers / antihistamines.