If something is inedible we do not treat it as Chameitz. However, if one puts that item in their mouth to digest it the Poskim debate if in doing so one gives the item the status of food. In that light I would recommend the following:
Medicine: Bitter or tasteless tablets, capsules, or liquids may be taken on Pesach even though they have chameitz ingredients. (If the medicine taken is in the form of pleasant tasting tablets or liquids an alternative should be found. If none is available, check in with a rabbi before discontinuing use.)
Vitamins: Ideally, a chameitz-free vitamin should be used. If none are available, then as long as the vitamin is bitter tasting or tasteless and prescribed by a doctor, the vitamins may be taken on Pesach.
Eye drops, ear drops, nose drops, and throat sprays do not need to be chameitz free.