a. Tetracyclines, quinolones, digoxin, indomethacin, iron, and salicylates
b. Coumarin anticoagulants, phenytoin, beta-blockers, benzodiazepines, lidocaine, theophylline, and tricyclic antidepressants
c. CNS depressants and muscle relaxants
d. Phenothiazines, tricyclic antidepressants, and opiate agonists