CommonSide Effects of Selgin are Constipation, Joint pain, Insomnia (difficulty in sleeping), Vomiting, Dizziness, Diarrhea, Confusion, Hallucination, Headache, Vertigo, Hypotension (low blood pressure), Slow heart rate, Muscle cramp, Fatigue, Breathlessness, Rash, Pharyngitis, Sinus inflammation, Mouth ulcer, Movement disorder, Increased liver enzymes.