While there are agencies that publish extensive lists of Kosher for Pesach medicines, the cRc policy, as directed by our late Rosh Beth Din HaRav Gedalia D. Schwartz, ztz"l and our Av Beth Din, HaRav Yona Reiss, is that medicinal non-chewable tablets, pills and capsules do not require Passover certification.
The source for this ruling is in the Shulchan Aruch [Orech Chaim 445:5] and is based upon the concept that medications (and creams) are not fit for human consumption. Therefore, even though they are swallowed since the person never considers this anything but medicine, even the concept of "achshavey" [lit. he makes it considered (as if it was food)] does not apply, and it is permitted to use [Ktav Sofer Orech Chaim 111; Chazon Ish 116:8; Iggrot Moshe Orech Chaim 2:92 and 3:62; Yichave Daat 2:60].
However, this only applies to pills and capsules. Syrups and lozenges may still be considered like food and, therefore, must be Kosher for Pesach [Shmirat Shabbat K'hilchata 40 note 163].
Of course, if a person is dangerously ill even medicine that is chametz may be consumed [Orech Chaim 466:1; Mishna Berura ibid., note 2].
