If you experience adverse reactions while taking Synthroid, it may be a sign that the dose is too high or too low. Speak with your doctor about any side effects. Common side effects of Synthroid medication include: Abdominal cramps, Anxiety, Arrhythmias, Diarrhea, Dyspnea, Emotional lability, Excessive sweating, Fatigue, Fever, Flushing, Hair loss, Headache, Heart failure, Heat intolerance, Increased appetite, Increased pulse and blood pressure, Insomnia, Irritability, Menstrual irregularities, Nervousness, Palpitations, Tachycardia, Weight loss Dr. Sheehy (BSc Molecular Biology, PharmD) works a clinical pharmacist specializing in cardiology, oncology, and ambulatory care. He’s a board-certified pharmacotherapy specialist (BCPS), and his experience working one-on-one with patients to fine tune their medication and therapy plans for optimal results makes him a valuable subject matter expert for our pharmacy.Read More....