Levothyroxine: Uses, Dosage, Side Effects, Interaction, Reviews
Levothyroxine, also known as L-thyroxine, is a medication used to treat hypothyroidism (a condition where the thyroid gland does not produce enough thyroid hormone). It is also used with surgery and radioactive iodine therapy to treat thyroid cancer. Levothyroxine is in a class of medications called hormones. It works by replacing the thyroid hormone that is normally produced by the body.
Without thyroid hormone, your body cannot function properly, which 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. When taken correctly, levothyroxine reverses these symptoms.
How should Levothyroxine be used?
Levothyroxine comes as a tablet and a capsule to take by mouth. It usually is taken once a day on an empty stomach, 30 minutes to 1 hour before breakfast. A new study indicates that when taken at bedtime, Levothyroxine significantly improved thyroid hormone levels. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take levothyroxine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Swallow capsules whole; do not chew or crush them. Do not remove the capsule from the package until you are ready to take it.
Take the tablets with a full glass of water as they may get stuck in your throat or cause choking or gagging.
If you are giving levothyroxine to an infant, child, or adult who cannot swallow the tablet, crush and mix it in 1 to 2 teaspoons (5 to 10 mL) of water. Only mix the crushed tablets with water; do not mix it with food or soybean infant formula. Give this mixture by spoon or dropper right away. Do not store it for later use.
Your doctor will probably start you on a low dose of levothyroxine and gradually increase your dose.
Levothyroxine controls hypothyroidism but does not cure it. It may take several weeks before you notice a change in your symptoms. Continue to take levothyroxine even if you feel well. Do not stop taking levothyroxine without talking to your doctor.
What are the side effects of Levothyroxine?
- Levothyroxine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- weight gain or loss
- headache
- vomiting
- diarrhea
- changes in appetite
- fever
- changes in menstrual cycle
- sensitivity to heat
- hair loss
- joint pain
- leg cramps
- Some side effects can be serious. If you experience either of the following symptoms, call your doctor immediately or get emergency medical treatment:
- shortness of breath, wheezing, hives, itching, rash, flushing, stomach pain, nausea, or swelling of hands, feet, ankles, or lower legs
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
What drugs Interacts with Levothyroxine?
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.
• Midodrine
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
• 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 Trisilicate
• Mestranol
• Omeprazole
• Pantoprazole
• Patiromer
• Phenytoin
• Polyestradiol Phosphate
• Promestriene
• Quinestrol
• Rabeprazole
• Rifampin
• Ritonavir
• Semaglutide
• Sevelamer
• Simvastatin
•         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 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
•         Soybean.
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