Levothyroxine (Tirosint) is a thyroid hormone used to treat hypothyroidism in adults and children ages 6 and older. It's available as a capsule in many different strengths. The capsule is usually taken once a day in the morning, about 30 minutes to 1 hour before breakfast, on an empty stomach. Common side effects include headache, nervousness, trouble sleeping, and weight loss. But it's important to note that this medication isn’t intended to be used for weight loss.
Hypothyroidism (low thyroid hormone levels)
Thyroid cancer (in combination with radiation and surgery)
Levothyroxine (Tirosint) is a lab-made version of the thyroid hormone called thyroxine or T4 that's made by your thyroid gland. Thyroid hormones have important functions like controlling your metabolism, body temperature, heart rate, and more. When the amount of hormone is too low, taking thyroid replacement hormones can bring your levels back to normal.
Source:Â DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Less common
Chest pain or discomfort
decreased urine output
difficult or labored breathing
difficulty with swallowing
dilated neck veins
extreme fatigue
fainting
fast, slow, irregular, pounding, or racing heartbeat or pulse
heat intolerance
hives or welts, skin itching, rash, or redness
irregular breathing
irritability
menstrual changes
pain or discomfort in the arms, jaw, back, or neck
sweating
swelling of the eyes, face, lips, throat, or tongue
tightness in the chest
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Change in consciousness
cold, clammy skin
confusion
disorientation
fast or weak pulse
lightheadedness
loss of consciousness
sudden headache
sudden loss of coordination
sudden slurring of speech
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
Abdominal or stomach cramps
change in appetite
crying
false or unusual sense of well-being
fear or nervousness
feeling not well or unhappy
feeling of discomfort
feeling of warmth
feeling things are not real
feelings of suspicion and distrust
headache
increased appetite
mental depression
muscle weakness
quick to react or overreact emotionally
rapidly changing moods
redness of the face, neck, arms, and occasionally, upper chest
restlessness
trouble getting pregnant
trouble sitting still
unusual tiredness or weakness
vomiting
weight gain or loss
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
First-choice medication for treating low thyroid hormone levels
Safe to use for all ages and during pregnancy
Only needs to be taken once a day
Capsule form allows for better absorption in the body compared to tablets
Might take months to find the right dose
Takes 4 to 6 weeks to see the full effects
Need to get regular blood tests to make sure you're taking the right dose
Interacts with many types of food, drinks, medications, and supplements
Take levothyroxine (Tirosint) 30 minutes to 1 hour before breakfast on an empty stomach. This helps the full amount of medication get absorbed into your body.
Swallow levothyroxine (Tirosint) capsules whole. Don't cut, crush, or chew it, as this can affect how the medication is absorbed and how well it works.
Keep levothyroxine (Tirosint) capsules in their blister packaging until you're ready to take them. Don't remove them from the original blister pack in advance.
Keep up with all of your follow-up appointments for lab testing while you're taking levothyroxine (Tirosint). Your prescriber will adjust your dose based on your thyroid hormone levels from your blood test results.
Many side effects of levothyroxine (Tirosint) are symptoms of hyperthyroidism (high thyroid hormone levels). Talk with your prescriber if you have symptoms like anxiety, fast heart rate, or unusual sweatiness because it might mean your dose is too high.
Take levothyroxine (Tirosint) at least 4 hours apart from calcium- or iron-containing medications and supplements, including antacids like calcium carbonate (Tums). These medications can prevent your body from absorbing levothyroxine (Tirosint) properly.
You might have some hair loss during the first few months of starting levothyroxine (Tirosint). This is usually rare and temporary; it should stop as you continue taking the medication.
Levothyroxine (Tirosint) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Taking other medications for weight loss
Levothyroxine (Tirosint) shouldn't be used for weight loss. It’s not recommended, safe, or effective for this use. Taking high doses of levothyroxine (Tirosint) can cause serious or life-threatening effects, especially if used with other medications for weight loss.
Risk factors: Current heart disease | Older adults
Taking too much levothyroxine (Tirosint) can cause heart problems, especially for older adults or people with heart conditions. Call your prescriber or get medical care right away if you have rapid or irregular heartbeat, chest pain, or trouble breathing. Your prescriber might need to reduce your dose or have you stop taking the medication altogether if you experience new heart problems.
Risk factors: Adrenal insufficiency | Addison's disease
In rare cases, some people can have low thyroid hormones and low adrenal hormones at the same time. If you have conditions, such as Addison's disease, where your body has low adrenal hormone levels, let your prescriber know. It's important that they treat your hormone levels first before they treat your thyroid condition. Otherwise, receiving thyroid hormones first can cause your adrenal hormones to drop even lower and make you feel unwell. Your prescriber should check your adrenal hormones before prescribing levothyroxine (Tirosint). If you experience long-lasting tiredness, stomach pain, dizziness, weakness, or vomiting while taking this medication, seek medical attention right away.
Risk factors: Taking diabetes medications
Levothyroxine (Tirosint) can raise your blood sugar levels, especially when you first start this medication and when your dose is raised. If you already have diabetes, your prescriber might need to adjust the dose of your blood sugar medications. Check your blood sugar levels as directed by your prescriber. Talk to your them if the levels are higher than usual.
Risk factors: Postmenopausal women | Higher doses
Taking levothyroxine (Tirosint) can weaken bones over time, especially if your dose is too high. The risk is higher for women after menopause . To lower your risk, your prescriber will be monitoring your thyroid levels to make sure you're taking the lowest dose needed to treat your thyroid condition. Make sure to get plenty of exercise, eat a bone-healthy diet, and avoid alcohol to lower your risk of bone problems.
Dosage | Quantity | Price as low as | Price per unit |
---|---|---|---|
30 capsules of 13mcg | 1 box | $121.85 | $121.85 |
30 capsules of 25mcg | 1 box | $121.85 | $121.85 |
30 capsules of 37.5mcg | 1 box | $121.85 | $121.85 |
30 capsules of 44mcg | 1 box | $121.85 | $121.85 |
30 capsules of 50mcg | 1 box | $121.85 | $121.85 |
30 capsules of 62.5mcg | 1 box | $121.85 | $121.85 |
30 capsules of 75mcg | 1 box | $121.85 | $121.85 |
30 capsules of 88mcg | 1 box | $121.85 | $121.85 |
30 capsules of 100mcg | 1 box | $121.85 | $121.85 |
30 capsules of 112mcg | 1 box | $121.85 | $121.85 |
30 capsules of 125mcg | 1 box | $121.85 | $121.85 |
30 capsules of 137mcg | 1 box | $121.85 | $121.85 |
30 capsules of 150mcg | 1 box | $121.85 | $121.85 |
30 capsules of 175mcg | 1 box | $121.85 | $121.85 |
30 capsules of 200mcg | 1 box | $121.85 | $121.85 |
Your provider will calculate your dose of levothyroxine (Tirosint) based on different factors, such as your age, medical condition, other medications you're taking, and the thyroid hormone levels in your blood.
The typical dose of levothyroxine (Tirosint) ranges from 13 mcg to 200 mcg taken by mouth once daily on an empty stomach.
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.
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.
Uncorrected adrenal insufficiency
Hypothyroidism (low thyroid hormone levels)
Thyroid cancer (in combination with radiation and surgery)
Hypothyroidism (low thyroid hormone levels)
Thyroid cancer (in combination with radiation and surgery)
Hypothyroidism (low thyroid hormone)
Lowering thyroid-stimulating hormone (TSH) levels in people with other thyroid problems like goiters or thyroid cancer
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IBSA Pharma Inc. (2024). Tirosint- lebothyroxine sodium capsule [package insert]. DailyMed.
Jonklaas, J., et al. (2014). Guidelines for the treatment of hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement. Thyroid.
Liu, H., et al. (2023). Levothyroxine: Conventional and novel drug delivery formulations. Endocrine Reviews.
MedlinePlus. (2024). Metabolism.
Wiesner, A., et al. (2021). Levothyroxine interactions with food and dietary supplements-a systematic review. Pharmaceuticals.
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