Even if unlikely, is systemic absorption of oral nystatin possible? since starting it, i've gotten bizarre heart palpitations, and-without fail-get some really weird ectopic beats about 20 minutes after each dose. is that otherwise seen w/ nystatin?

Possible: Some absorption of a topical medication is expected even though the amount may be minor. In case there has been a breach on the surface integrity on the intestinal surface, the amount absorbed can be higher. Regardless, if you are experiencing side effects, you need to contact your doctor immediately. Since this is not a life-sustaining drug, do consider stopping it now.