Pharmaxin Chloramphenicol Phenytoin Sodium
ModeratePhenytoin sodium speeds up the way the body breaks down chloramphenicol (it increases its metabolism). The leaflet lists this together with HMG-CoA reductase inhibitors, TCAs and other medicines, but only the chloramphenicol part concerns you here.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.