Common Lanoxin side effects may include: Dizziness, Fainting, Irregular heartbeat, Slow heartbeat, Agitation or combativeness, Anxiety, Confusion, Depression, Diarrhea, Expressed fear of impending death, Hallucinations, Rash, Vomiting, Double vision, Halos around lights, Headache, Lack of feeling or emotion, Loss of appetite, Night blindness, Over bright appearance of lights, Swelling of the breasts or breast soreness in both females and males, Tunnel vision, Weakness, Weight loss Black tarry stools, Bleeding gums, Hematuria, Bloody stools, Bloody vomit, Pinpoint red spots on the skin, Rash with flat lesions or small raised lesions on the skin, Severe stomach pain, Unusual bleeding or bruising