What It's For & How To Take
Levothyroxine is a thyroid hormone used when your body is not able to produce enough thyroid hormone on its own. In some conditions, the thyroid is partially working while in other conditions they thyroid may not produce any thyroid hormone at all.
The thyroid may decrease in its function naturally over time, or it may become damaged through injury, certain medications, radiation therapy or certain types of disease conditions.
Maintaining an appropriate thyroid level is important for normal mental and physical function. In children, a normal thyroid level is necessary for mental and physical growth.
Low thyroid hormone may result in poor growth, slow speech, lack of energy, excessive tiredness, constipation, weight gain, hair loss, dry, thick skin, increased sensitivity to cold, joint and muscle pain, heavy or irregular menstrual periods, and depression. Treatment with levothyroxine may help to decrease or even reverse these symptoms.
Levothyroxine is usually taken once daily on an empty stomach, 30 minutes before or 1 hour after breakfast. This medication should be taken at least 4 hours before or after any items containing aluminum or iron such as antacids or multivitamins. These items may decrease the absorption of this medication.
If you miss a dose, take it as soon as you remember. If it is near the time of your next dose, skip it and continue with your normal dose time. Do not take a double dose to make up the missed dose.
Take this medication regularly to get the full benefit. Your dose is based on your condition, response to therapy and blood level. Thyroid hormone replacement therapy is usually taken for life.
Normally, you will have a blood test to check your thyroid level every 6-8 weeks until your level is normal. You will then be tested 8-12 weeks after any dosage change and every 6-12 months throughout therapy. If you have not had a lab test done for 12 months or more, talk to your doctor about it.
Most Important Warnings
- This medication is not used for weight loss. Normal doses will not work for weight loss. Larger doses may cause potentially life threating toxicity.
Warnings & Cautions
- There are multiple brands of levothyroxine available on the market. Even though they are all dosed the same, it is possible that the absorption may be a little different from one brand to another. Know which brand you take. Ask your pharmacist for the same brand of levothyroxine each time you get a refill. If you need to change from one brand to another, you will need to have a blood level done after 6-8 weeks of therapy with the new brand.
- Let your pharmacist or doctor know if you are pregnant or breastfeeding before taking this medication.
Interactions & Side Effects
- Tell your pharmacist or doctor all your medication allergies so they may determine if levothyroxine is safe for you to take.
- Avoid dangerous drug interactions. Tell your pharmacist or doctor all the other medication you are taking, including over the counter supplements, even if you don't take them very often.
- Ask your doctor if this medication is safe to take with your current health conditions. Tell your doctor if you have a history of increased thyroid hormone, any heart disease, high blood pressure, diabetes, or any other medical condition,
- While taking levothyroxine, you may notice some hair loss during the first few months of therapy. This is normal and temporary. If these or any other unwanted side effects persist, contact your doctor or pharmacist to talk about it with them.
- Call your doctor right away if you have any increased sweating, sensitivity to heat, significant mood changes, shaking, swelling in hands or feet or have a pounding heartbeat.
- Call emergency 911 if you have any symptoms of a heart attack such as chest and left arm pain, shortness of breath and sweating or if you have symptoms of a stroke such as weakness on one side of your body, slurred speech, sudden vision changes, and confusion.