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Tirosint

levothyroxine
Used for Hypothyroidism, Thyroid Cancer

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.

Reviewed by:Last reviewed on October 21, 2024
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What is Levothyroxine (Tirosint)?

What is Levothyroxine (Tirosint) used for?

  • Hypothyroidism (low thyroid hormone levels)
  • Thyroid cancer (in combination with radiation and surgery)

How Levothyroxine (Tirosint) works

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.

When does Levothyroxine (Tirosint) start working?Time passed since treatment started:
HOURS
DAYS
WEEKS
Full effect
MONTHS

Drug facts

Common Brands
Drug ClassThyroxine (T4)
Controlled Substance ClassificationNot a controlled medication
Generic StatusLower-cost generic available
AvailabilityPrescription only
side-effects-icon

Side effects of Levothyroxine (Tirosint)

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Signs of having too much thyroid hormones in the body, such as:

  • Irregular heartbeat
  • Chest pain
  • Shortness of breath
  • Leg cramps
  • Headache
  • Nervousness
  • Hives or skin rash
  • Irritability
  • Trouble sleeping
  • Tremors
  • Muscle weakness
  • Change in appetite
  • Weight loss
  • Vomiting
  • Diarrhea
  • Sweating a lot
  • Sensitivity to heat
  • Fever
  • Changes in menstrual period

Less Common Side Effects

  • Tiredness
  • Anxiety
  • Muscle spasm
  • Fast heart rate
  • Stomach cramps
  • Hair loss
  • Flushing
  • Rash

Levothyroxine (Tirosint) serious side effects

Contact your healthcare provider immediately if you experience any of the following.

  • Heart failure: trouble breathing; weakness; tiredness; swelling in the hands, ankles, and feet
  • Heart attack: dizziness, lightheadedness, anxiety, trouble breathing, fast heartbeat, nausea, cold sweat, clammy skin, chest pain or tightness
When do Levothyroxine (Tirosint) possible side effects begin and end?
Time passed since treatment started:
H
D
W
M
Symptoms of too much thyroid hormone
Seek immediate medical care if you experience this side effect.
If a line continues to the right, you'll likely keep experiencing this side effect once it starts.

Source: DailyMed

The following Levothyroxine (Tirosint) side effects have also been reported

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

fever

heat intolerance

hives or welts, skin itching, rash, or redness

irregular breathing

irritability

menstrual changes

nausea

pain or discomfort in the arms, jaw, back, or neck

sweating

swelling of the eyes, face, lips, throat, or tongue

tightness in the chest

tremors

Rare

Blurred or double vision

dizziness

eye pain

lack or slowing of normal growth in children

limp or walk favoring one leg

pain in the hip or knee

seizures

severe headache

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

diarrhea

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

hair loss

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.

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Pros and cons of Levothyroxine (Tirosint)

Pros

Cons

  • 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
pharmacist-tips-icon

Pharmacist tips for Levothyroxine (Tirosint)

pharmacist
  • 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.
faq-icon

Common questions about Levothyroxine (Tirosint)

It can take up to 4 to 6 weeks after you start levothyroxine (Tirosint) before you experience the full benefit this medication. But some people might notice an improvement in their symptoms sooner than that. If you're starting levothyroxine (Tirosint) for the first time, it might take months before your prescriber can find a dose that works best for you. During this time, they'll order blood work to check your thyroid hormone levels to make sure it's within the target range. Your prescriber might need to raise your dose slowly over time, to avoid side effects of having too much thyroid hormone, such as anxiety, headache, and nausea.

Levothyroxine (Tirosint) interacts with many medications. Some interactions lead reduce the absorption of levothyroxine (Tirosint), which means it won't work as well. And others can lead to too levothyroxine (Tirosint) in your body. To avoid these interactions, it's recommended to take levothyroxine (Tirosint) on an empty stomach. How long you should wait between taking it and other medications can depend on the specific medication. For example, some antacids (e.g., calcium carbonate) should be taken 4 hours away from levothyroxine (Tirosint). Check with your pharmacist or prescriber for how long you should wait before taking your other medications.

Eating too soon after taking levothyroxine (Tirosint) can make it harder for your body to absorb the medication. For example, foods high in fiber, soy products, and walnuts can reduce the absorption of levothyroxine (Tirosint). For this reason, it's recommended to take your dose at least 30 minutes to 1 hour before food.

You can take levothyroxine (Tirosint) at bedtime, but make sure it's 4 hours after the last meal. Research shows levothyroxine (Tirosint) can work just as well at night as it does in the morning, as long as you separate it from food and other medications.

Try to wait 1 hour after taking your dose of levothyroxine (Tirosint) before drinking coffee. Drinking coffee with levothyroxine (Tirosint) can lower the amount of medication your body absorbs.

Weight gain isn't a known side effect of levothyroxine (Tirosint). But it's possible for you to experience weight gain while taking this medication if the dose of levothyroxine (Tirosint) isn't enough to bring your thyroid hormone levels up to the target range. If you have weight gain while taking levothyroxine (Tirosint), let your prescriber know. They might need to check your thyroid hormone level to make sure your dose is appropriate.

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Risks and warnings for Levothyroxine (Tirosint)

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.

Not for weight loss

  • Risk factors: Taking other medications for weight loss

Black Box Warning 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.

Heart problems

  • 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.

Dangerously low stress hormone levels (adrenal crisis)

  • 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.

Worsening diabetes

  • 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.

Effects on bones

  • 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-icon

Levothyroxine (Tirosint) dosage

The average cost for 1 box of 30 capsules of 75mcg of Levothyroxine (Tirosint) is $113.08 with a free GoodRx coupon. This is 38.09% off the average retail price of $182.65.
boxBox
DosageQuantityPrice as low asPrice per unit
30 capsules of 13mcg1 box$89.67$89.67
30 capsules of 25mcg1 box$104.17$104.17
30 capsules of 50mcg1 box$122.37$122.37
30 capsules of 75mcg1 box$113.08$113.08
30 capsules of 112mcg1 box$78.25$78.25
30 capsules of 125mcg1 box$103.53$103.53
30 capsules of 137mcg1 box$72.05$72.05
30 capsules of 150mcg1 box$106.76$106.76
30 capsules of 88mcg1 box$110.72$110.72
30 capsules of 100mcg1 box$96.71$96.71
30 capsules of 175mcg1 box$103.43$103.43
30 capsules of 200mcg1 box$120.24$120.24
30 capsules of 62.5mcg1 box$127.54$127.54
30 capsules of 37.5mcg1 box$127.54$127.54
30 capsules of 44mcg1 box$127.54$127.54

Typical dosage for Levothyroxine (Tirosint)

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.

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Interactions between Levothyroxine (Tirosint) and other drugs

Levothyroxine (Tirosint) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Levothyroxine (Tirosint). Please note that only the generic name of each medication is listed below.

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.

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.

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Levothyroxine (Tirosint) contraindications

Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Levothyroxine (Tirosint) will not be safe for you to take.

  • Uncorrected adrenal insufficiency
alternatives-icon

What are alternatives to Levothyroxine (Tirosint)?

There are a number of medications that your doctor can prescribe in place of Levothyroxine (Tirosint). Compare a few possible alternatives below.
Levothyroxine (Tirosint)
Used for:
  • Hypothyroidism (low thyroid hormone levels)
  • Thyroid cancer (in combination with radiation and surgery)
$63.27Lowest GoodRx priceView prices
Synthroid (levothyroxine)
Used for:
$3.00Lowest GoodRx priceView prices
Armour Thyroid (desiccated thyroid)
Used for:
$31.20Lowest GoodRx priceView prices
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Levothyroxine (Tirosint) images

Amber H - TIROSINT 75mcg Capsule
This medicine is Amber Box Imprinted With "H".Amber H - TIROSINT 75mcg Capsule

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References

Best studies we found

Eghtedari, B., et al. (2023). Levothyroxine. StatPearls.

Haddady, S. (2018). Hypothyroidism: Body weight appears to be the main levothyroxine dose adjustment variable. Clinical Thyroidology for the Public.

IBSA Pharma Inc. (2024). Tirosint- lebothyroxine sodium capsule [package insert]. DailyMed.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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