Before Using

Drug information provided by: Merative, Micromedex®

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of levothyroxine in children. However, your child's doctor will check your child closely for heart problems during the first 2 weeks of treatment.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of levothyroxine in the elderly. However, elderly patients are more likely to have age-related heart or blood vessel problems, which may require caution and an adjustment in the dose for patients receiving levothyroxine.

Breastfeeding

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Apixaban
  • Dabigatran Etexilate
  • Digitalis
  • Edoxaban
  • Furosemide
  • Iopromide
  • Ketamine
  • Midodrine
  • Rivaroxaban
  • Warfarin

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Aluminum Carbonate, Basic
  • Aluminum Hydroxide
  • Aluminum Phosphate
  • Calcium Acetate
  • Calcium Carbonate
  • Calcium Citrate
  • Calcium Silicate
  • Chlorotrianisene
  • Cholestyramine
  • Chromium
  • Ciprofloxacin
  • Colesevelam
  • Conjugated Estrogens
  • Conjugated Estrogens Synthetic A
  • Conjugated Estrogens Synthetic B
  • Dexlansoprazole
  • Dienestrol
  • Diethylstilbestrol
  • Dihydroxyaluminum Aminoacetate
  • Dihydroxyaluminum Sodium Carbonate
  • Esomeprazole
  • Esterified Estrogens
  • Estradiol
  • Estramustine
  • Estriol
  • Estropipate
  • Ethinyl Estradiol
  • Fosphenytoin
  • Imatinib
  • Iron
  • Kelp
  • Lansoprazole
  • Lanthanum Carbonate
  • Lopinavir
  • Magaldrate
  • Magnesium Carbonate
  • Magnesium Hydroxide
  • Magnesium Oxide
  • Magnesium Peroxide
  • Magnesium Trisilicate
  • Mestranol
  • Omeprazole
  • Pantoprazole
  • Patiromer
  • Phenytoin
  • Polyestradiol Phosphate
  • Promestriene
  • Quinestrol
  • Rabeprazole
  • Rifampin
  • Ritonavir
  • Semaglutide
  • Sevelamer
  • Simvastatin
  • Sodium Bicarbonate
  • Tibolone

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

  • Dietary Fiber
  • Grapefruit Juice
  • Soybean
  • Walnut

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

  • Enteral Nutrition

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Adrenal gland insufficiency (underactive adrenal gland), untreated or
  • Heart attack, acute or recent or
  • Thyrotoxicosis (overactive thyroid), untreated—Should not be used in patients with these conditions.
  • Adrenal gland problems or
  • Anemia, pernicious or
  • Angina (severe chest pain), history of or
  • Blood clotting problems, or history of or
  • Diabetes or
  • Heart or blood vessel disease (eg, coronary artery disease, heart failure), history of or
  • Heart rhythm problems (eg, arrhythmia, atrial fibrillation), history of or
  • Osteoporosis, history of—Use with caution. May make these conditions worse.
  • Hypoproteinemia (low levels of protein in the blood), severe or
  • Kidney disease (eg, nephrosis) or
  • Liver disease (eg, hepatitis), severe or
  • Pituitary gland problems (eg, acromegaly) or
  • Porphyria (enzyme problem)—Use with caution. May need to adjust the dose of levothyroxine in patients with these conditions.
  • Patients who have trouble swallowing capsules (including children younger than 6 years of age)—Tirosint® should not be given in these patients.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.

Portions of this document last updated: April 01, 2024

Copyright: © Merative US L.P. 1973, 2024. All rights reserved. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes.