Common causes of tachycardia include: strong emotional responses, such as fear, stress or anxiety, strenuous exercise, caffeine, nicotine, fever, taking cold and cough medications that contain pseudoephedrine, a stimulant and taking some asthma inhaler medications that contain stimulants. Sometimes, tachycardia can be a sign of a serious health problem, such as an overactive thyroid gland (hyperthyroidism), abnormal heart rhythm (cardiac arrhythmia) or anemia. You have mentioned the name of medication which you used for treatment of tachycardia. Advice 1. Take rest and avoid all sorts of strenuous activity. 2. Avoid coffee, alcohol and smoking 3. Investigation – Hb%, ECG 4. Consult your doctor so that he would restart treatment medication Thanks