This medication may cause constipation, lightheadedness, dizziness, drowsiness, stomach upset, nausea or flushing the first few days as your body adjusts to the medication. If these symptoms persist or become bothersome, inform your doctor. Notify your doctor if you develop: irregular or slow heartbeat, anxiety, tremors, seizures. If the area around the patch becomes red, itchy or irritated, try a new site. If the irritation continues or becomes worse, contact your doctor.