Some side effects that are usually encountered while taking generic Lanoxicaps include fast, slow, or uneven heart rate; bloody or black, tarry stools; blurred vision, yellowed vision; confusion, hallucinations, unusual thoughts or behavior, mild nausea, vomiting, diarrhea; feeling weak or dizzy; headache; enlarged breasts in men; or mild skin rash. Contact a local physician if any of these adverse effects, or others not listed, occur during treatment with Lanoxicaps.