Hi Welcome to HCM. I appreciate your concern for the safety and instructions for Levothyroxine. Levothyroxine is a replacement for a hormone normally produced by your thyroid gland to regulate the body s energy and metabolism. Uses: 1. Treatment of Hypothyroidism 2. To treat or prevent goiter (enlarged thyroid gland), which can be caused by hormone imbalances, radiation treatment, surgery, or cancer. 3. To treat congenital hypothyroidism (cretinism). Side effects: weight loss, tremor, headache, nausea, vomiting, diarrhea, stomach cramps, nervousness, increased pulse rate, palpitation and chest pain etc. It is best to take this medicine on an empty stomach. The capsules should be swallowed as a whole; should not be chewed or crushed. Take it with a full glass of water at least 30 minutes to 1 hour before eating breakfast. You should not take Levothyroxine as with the following medications. This medicine should be taken at least 4 hours before or 4 hours after these medications: antacids, calcium supplements, cholestyramine, colestipol, iron supplements, orlistat, simethicone, and sucralfate. Hope this answers your query, Rate this answer, if you are convinced.