It is recommended that you take the drug first thing in the morning with a full glass of water, about an hour before breakfast. You should avoid food and other medications for an hour after taking levothyroxine, and make sure to take it four hours before or after taking iron supplements, calcium supplements, or antacids. At your doctor’s discretion, you might need to avoid foods that affect the absorption of levothyroxine, including soybeans, walnuts, grapefruit, and high-fiber foods.

Common side effects include nausea, weight changes, stomach upset, mood changes, and headaches. Tell your doctor straight away if you have symptoms such as chest pain, changes in heartbeat, uncontrollable shaking, nervousness, anxiety, irritability, sleep difficulties, shortness of breath, or excessive sweating, as these can be a sign of a serious problem.

Also, make sure to inform your doctor of all other medications (including over-the-counter drugs and supplements) you are taking in order to prevent drug interactions. This paragraph is only an overview, and it is not intended to replace medical counseling; please consult your pharmacist and/or medical provider for more comprehensive information.

HOW TO USE: Take this medication by mouth as directed by your doctor, usually once daily on an empty stomach, 30 minutes to 1 hour before breakfast. Take this medication with a full glass of water unless your doctor directs you otherwise. If you are taking the capsule form of this medication, swallow it whole. Do not split, crush, or chew. People who cannot swallow the capsule whole (such as infants or small children) should use the tablet form of the medication. For infants or children who cannot swallow whole tablets, crush the tablet and mix in 1 to 2 teaspoons (5 to 10 milliliters) of water, and give using a spoon or dropper immediately. Do not prepare a supply in advance or mix the tablet in soy infant formula. Consult your pharmacist for more information.