Tirosint 37.5mcg Capsules
WARNING: Do not use this drug for weight loss. Severe and sometimes deadly side effects may happen with this drug if it is taken in large doses or with other drugs for weight loss. If you have questions, talk with the doctor. @ COMMON USES: It is used to add thyroid hormone to the body.It is used to manage thyroid cancer.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Thyroid hormone
Pharmacologic Class
Thyroid replacement
Pregnancy Category
Category A
FDA Approved
Aug 2000
DEA Schedule
Not Controlled
Overview
What is this medicine?
Levothyroxine is a medicine that replaces a hormone normally made by your thyroid gland. It's used when your thyroid gland doesn't make enough of this hormone (a condition called hypothyroidism). Taking this medicine helps your body work properly, improving symptoms like tiredness, weight gain, and feeling cold. Tirosint is a specific brand of this medicine that comes in a liquid-filled capsule, which might be easier for some people to absorb or if they have allergies to inactive ingredients in tablet forms.
How to Use This Medicine
Taking Your Medication Correctly
To ensure you get the most benefit from your medication, follow these instructions carefully:
Take your medication exactly as directed by your doctor. Read all the information provided with your prescription and follow the instructions closely.
Take your medication on an empty stomach, at least 30 to 60 minutes before breakfast.
Swallow the capsule whole - do not chew, break, or crush it.
Avoid taking iron products, antacids containing aluminum or magnesium, or calcium carbonate within 4 hours before or 4 hours after taking your medication.
If you take other medications, they may need to be taken at a different time than your current medication. Consult with your doctor or pharmacist to determine the best schedule.
Certain foods, such as soybean flour (found in infant formula), may interact with your medication. Discuss this with your doctor.
If you regularly consume grapefruit juice or eat grapefruit, talk to your doctor about potential interactions.
Be aware that there are different brands and forms of this medication. Do not switch between them without consulting your doctor.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, away from the bathroom.
Protect your medication from heat and light.
Do not remove your medication from the blister pack until you are ready to take it. Take the medication immediately after opening the blister pack, and do not store the removed medication for future use.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember.
If it is close to the time for your next dose, skip the missed dose and resume your regular schedule.
Do not take two doses at the same time or take extra doses.
To ensure you get the most benefit from your medication, follow these instructions carefully:
Take your medication exactly as directed by your doctor. Read all the information provided with your prescription and follow the instructions closely.
Take your medication on an empty stomach, at least 30 to 60 minutes before breakfast.
Swallow the capsule whole - do not chew, break, or crush it.
Avoid taking iron products, antacids containing aluminum or magnesium, or calcium carbonate within 4 hours before or 4 hours after taking your medication.
If you take other medications, they may need to be taken at a different time than your current medication. Consult with your doctor or pharmacist to determine the best schedule.
Certain foods, such as soybean flour (found in infant formula), may interact with your medication. Discuss this with your doctor.
If you regularly consume grapefruit juice or eat grapefruit, talk to your doctor about potential interactions.
Be aware that there are different brands and forms of this medication. Do not switch between them without consulting your doctor.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, away from the bathroom.
Protect your medication from heat and light.
Do not remove your medication from the blister pack until you are ready to take it. Take the medication immediately after opening the blister pack, and do not store the removed medication for future use.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember.
If it is close to the time for your next dose, skip the missed dose and resume your regular schedule.
Do not take two doses at the same time or take extra doses.
Lifestyle & Tips
- Take on an empty stomach, typically 30-60 minutes before breakfast, with a full glass of water.
- Avoid taking with calcium, iron, antacids, or other medications that interfere with absorption. Separate by at least 4 hours.
- Take consistently at the same time each day.
- Do not stop taking this medication without consulting your doctor, even if you feel better.
- Inform your doctor about all other medications, supplements, and herbal products you are taking, as many can interact with levothyroxine.
- Report any new or worsening symptoms, especially signs of overactive thyroid (e.g., rapid heart rate, nervousness, sweating, weight loss) or underactive thyroid (e.g., extreme fatigue, weight gain, constipation).
- Regular blood tests (TSH) are necessary to ensure the correct dose.
Available Forms & Alternatives
Available Strengths:
- Tirosint 13mcg Capsules
- Tirosint 25mcg Capsules
- Tirosint 50mcg Capsules
- Tirosint 75mcg Capsules
- Tirosint 88mcg Capsules
- Tirosint 150mcg Capsules
- Tirosint 137mcg Capsules
- Tirosint 100mcg Capsules
- Tirosint 112mcg Capsules
- Tirosint 125mcg Capsules
- Tirosint 175mcg Capsules
- Tirosint 200mcg Capsules
- Tirosint-Sol 100mcg/ml Oral Sol
- Tirosint-Sol 137mcg/ml Oral Sol
- Tirosint-Sol 150mcg/ml Oral Sol
- Tirosint-Sol 175mcg/ml Oral Sol
- Tirosint-Sol 88mcg/ml Oral Sol
- Tirosint-Sol 200mcg/ml Oral Sol
- Tirosint-Sol 13mcg/ml Oral Sol
- Tirosint-Sol 25mcg/ml Oral Sol
- Tirosint-Sol 50mcg/ml Oral Sol
- Tirosint-Sol 112mcg/ml Oral Sol
- Tirosint-Sol 75mcg/ml Oral Sol
- Tirosint-Sol 125mcg/ml Oral Sol
- Tirosint-Sol 37.5mcg/ml Oral Sol
- Tirosint-Sol 44mcg/ml Oral Sol
- Tirosint-Sol 62.5mcg/ml Oral Sol
- Tirosint 37.5mcg Capsules
- Tirosint 44mcg Capsules
- Tirosint 62.5mcg Capsules
Dosing & Administration
Adult Dosing
Standard Dose:
Highly individualized, typically 1.6 mcg/kg/day orally once daily for primary hypothyroidism. Tirosint 37.5mcg is a specific strength used for fine-tuning or specific patient needs.
Dose Range:
25 - 300 mg
Condition-Specific Dosing:
primaryHypothyroidism:
Initial: 1.6 mcg/kg/day orally once daily. Adjust by 12.5-25 mcg increments every 4-6 weeks based on TSH levels. Elderly or cardiac patients: Initial 12.5-25 mcg/day, titrate slowly.
subclinicalHypothyroidism:
Initial: 25-75 mcg/day orally once daily. Adjust based on TSH.
thyroidCancerSuppression:
Higher doses, typically 2.0-2.7 mcg/kg/day, to suppress TSH below target levels (e.g., <0.1 mIU/L).
Pediatric Dosing
Neonatal:
Congenital Hypothyroidism: Initial 10-15 mcg/kg/day orally once daily. Adjust based on TSH and T4.
Infant:
0-3 months: 10-15 mcg/kg/day; 3-6 months: 8-10 mcg/kg/day; 6-12 months: 6-8 mcg/kg/day. Adjust based on TSH and T4.
Child:
1-5 years: 5-6 mcg/kg/day; 6-12 years: 4-5 mcg/kg/day. Adjust based on TSH and T4.
Adolescent:
12-17 years: 2-3 mcg/kg/day or 1.6 mcg/kg/day (full adult replacement dose). Adjust based on TSH and T4.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment needed.
Moderate:
No specific adjustment needed.
Severe:
No specific adjustment needed.
Dialysis:
No specific adjustment needed. Levothyroxine is highly protein-bound and not significantly removed by dialysis.
Hepatic Impairment:
Mild:
No specific adjustment needed.
Moderate:
No specific adjustment needed.
Severe:
No specific adjustment needed.
Pharmacology
Mechanism of Action
Levothyroxine sodium is a synthetic L-isomer of thyroxine (T4), which is converted to its active metabolite, L-triiodothyronine (T3), in peripheral tissues. T3 and T4 bind to thyroid hormone receptors in the cell nucleus, regulating gene expression and controlling numerous metabolic processes, including protein, carbohydrate, and lipid metabolism, and influencing growth and development.
Pharmacokinetics
Absorption:
Bioavailability:
40-80% (highly variable, influenced by food, gastric pH, and other medications)
Tmax:
2-4 hours
FoodEffect:
Food significantly decreases absorption. Should be taken on an empty stomach, 30-60 minutes before breakfast, and at least 4 hours apart from calcium, iron, and antacids.
Distribution:
Vd:
Approximately 10-13 L
ProteinBinding:
>99% (primarily to thyroxine-binding globulin (TBG), transthyretin, and albumin)
CnssPenetration:
Limited (T4 crosses BBB, but T3 is more active in CNS)
Elimination:
HalfLife:
Approximately 6-7 days (euthyroid); 9-10 days (hypothyroid); 3-4 days (hyperthyroid)
Clearance:
Approximately 0.05 L/hour
ExcretionRoute:
Primarily renal (conjugated metabolites), small amount fecal (unabsorbed drug and biliary excretion)
Unchanged:
<1% (renal)
Pharmacodynamics
OnsetOfAction:
Gradual, clinical effects typically seen within 3-5 days, but full therapeutic effect may take 4-6 weeks due to long half-life and need for TSH stabilization.
PeakEffect:
TSH levels stabilize after 4-6 weeks of consistent dosing.
DurationOfAction:
Effects persist for several days after discontinuation due to long half-life.
Safety & Warnings
BLACK BOX WARNING
Thyroid hormones, including Tirosint, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
Side Effects
Serious Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood pressure, including:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Chest pain or pressure
Fast or abnormal heartbeat
Shortness of breath
Sudden weight gain or swelling in the arms or legs
Headache
Feeling tired or weak
Changes in appetite
Unintentional weight changes
Diarrhea, stomach cramps, or vomiting
Mood changes, such as feeling irritable, nervous, excitable, anxious, or restless
Shakiness
Trouble sleeping
Sensitivity to heat
Excessive sweating
Fever
Muscle cramps
Muscle weakness
Flushing
Bone pain
Changes in menstrual periods (in women)
In children: hip or knee pain, or a limp
In infants: changes in the shape of the head and face
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor for advice:
* Hair loss (usually temporary and resolves on its own within the first few months of treatment)
Reporting Side Effects
If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high blood pressure, including:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Chest pain or pressure
Fast or abnormal heartbeat
Shortness of breath
Sudden weight gain or swelling in the arms or legs
Headache
Feeling tired or weak
Changes in appetite
Unintentional weight changes
Diarrhea, stomach cramps, or vomiting
Mood changes, such as feeling irritable, nervous, excitable, anxious, or restless
Shakiness
Trouble sleeping
Sensitivity to heat
Excessive sweating
Fever
Muscle cramps
Muscle weakness
Flushing
Bone pain
Changes in menstrual periods (in women)
In children: hip or knee pain, or a limp
In infants: changes in the shape of the head and face
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor for advice:
* Hair loss (usually temporary and resolves on its own within the first few months of treatment)
Reporting Side Effects
If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Chest pain
- Palpitations or rapid heart rate
- Shortness of breath
- Excessive sweating
- Tremors
- Nervousness or irritability
- Insomnia
- Unexplained weight loss
- Diarrhea
- Fever
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Certain health conditions, including:
+ An overactive thyroid gland
+ A weak adrenal gland
+ Difficulty swallowing
This list is not exhaustive, and it is crucial to discuss all your health problems with your doctor.
Additionally, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking
Any natural products or vitamins you are using
Your health problems
This information will help your doctor determine if it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Certain health conditions, including:
+ An overactive thyroid gland
+ A weak adrenal gland
+ Difficulty swallowing
This list is not exhaustive, and it is crucial to discuss all your health problems with your doctor.
Additionally, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking
Any natural products or vitamins you are using
Your health problems
This information will help your doctor determine if it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
Important Information for All Patients Taking This Medication
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. To ensure uninterrupted treatment, do not allow your supply of this medication to run out. Please note that it may take several weeks to experience the full effects of this medication.
Special Considerations
If you have diabetes (high blood sugar), consult with your doctor, as this medication may affect blood sugar control. Your doctor may need to adjust your diabetes medications. Be sure to monitor your blood sugar levels as directed by your doctor and undergo regular blood tests as recommended.
If you are taking biotin or a product containing biotin, stop taking it at least 2 days before having your thyroid levels checked to ensure accurate test results.
Potential Risks and Side Effects
High doses of this medication may increase the risk of developing weak bones (osteoporosis), particularly after menopause. Discuss your individual risk factors with your doctor, who can help determine if you are at higher risk.
This medication may also affect fertility, potentially leading to difficulties getting pregnant or fathering a child. If you plan to become pregnant or father a child, consult with your doctor before starting treatment.
Age-Related Considerations
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor, who will discuss the benefits and risks of this medication to you and your baby.
Pediatric Patients
If you are giving this medication to a child and their weight changes, consult with your doctor, as the dosage may need to be adjusted. Never give your child more of this medication than prescribed, as this can increase the risk of severe side effects.
In some cases, this medication may affect growth in children and teenagers. Regular growth checks may be necessary, so be sure to discuss this with your doctor.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. To ensure uninterrupted treatment, do not allow your supply of this medication to run out. Please note that it may take several weeks to experience the full effects of this medication.
Special Considerations
If you have diabetes (high blood sugar), consult with your doctor, as this medication may affect blood sugar control. Your doctor may need to adjust your diabetes medications. Be sure to monitor your blood sugar levels as directed by your doctor and undergo regular blood tests as recommended.
If you are taking biotin or a product containing biotin, stop taking it at least 2 days before having your thyroid levels checked to ensure accurate test results.
Potential Risks and Side Effects
High doses of this medication may increase the risk of developing weak bones (osteoporosis), particularly after menopause. Discuss your individual risk factors with your doctor, who can help determine if you are at higher risk.
This medication may also affect fertility, potentially leading to difficulties getting pregnant or fathering a child. If you plan to become pregnant or father a child, consult with your doctor before starting treatment.
Age-Related Considerations
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor, who will discuss the benefits and risks of this medication to you and your baby.
Pediatric Patients
If you are giving this medication to a child and their weight changes, consult with your doctor, as the dosage may need to be adjusted. Never give your child more of this medication than prescribed, as this can increase the risk of severe side effects.
In some cases, this medication may affect growth in children and teenagers. Regular growth checks may be necessary, so be sure to discuss this with your doctor.
Overdose Information
Overdose Symptoms:
- Palpitations
- Tachycardia (rapid heart rate)
- Arrhythmias (irregular heart rhythm)
- Chest pain (angina)
- Tremor
- Nervousness
- Insomnia
- Diaphoresis (sweating)
- Heat intolerance
- Weight loss
- Diarrhea
- Vomiting
- Fever
- Seizures (rare)
- Coma (rare)
What to Do:
Seek immediate medical attention or call Poison Control at 1-800-222-1222. Treatment is symptomatic and supportive, including gastric lavage, activated charcoal, beta-blockers for cardiac symptoms, and cooling measures for fever.
Drug Interactions
Major Interactions
- Amiodarone (alters thyroid hormone metabolism)
- Oral anticoagulants (may increase anticoagulant effect)
- Sympathomimetics (increased risk of cardiac effects)
- Tyrosine kinase inhibitors (e.g., imatinib, sunitinib, sorafenib - may increase levothyroxine requirements)
- Orlistat (may reduce levothyroxine absorption)
- Ion exchange resins (e.g., cholestyramine, colestipol, sevelamer, patiromer - reduce absorption)
- Sucralfate (reduces absorption)
- Proton pump inhibitors (e.g., omeprazole, lansoprazole - reduce absorption by increasing gastric pH)
- H2 blockers (e.g., cimetidine, ranitidine - reduce absorption by increasing gastric pH)
- Antacids (aluminum and magnesium hydroxide, calcium carbonate - reduce absorption)
- Iron supplements (ferrous sulfate - reduce absorption)
- Calcium supplements (calcium carbonate - reduce absorption)
- Soy products (may reduce absorption)
- Dietary fiber (may reduce absorption)
- Rifampin (increases levothyroxine metabolism)
- Phenytoin (increases levothyroxine metabolism)
- Carbamazepine (increases levothyroxine metabolism)
- Phenobarbital (increases levothyroxine metabolism)
- Estrogens (increase TBG, increasing levothyroxine requirements)
- Androgens (decrease TBG, decreasing levothyroxine requirements)
- Glucocorticoids (may inhibit TSH secretion and T4 to T3 conversion)
Moderate Interactions
- Beta-blockers (may reduce conversion of T4 to T3)
- Digoxin (levothyroxine may decrease digoxin levels)
- Antidiabetic agents (levothyroxine may increase blood glucose, requiring dose adjustment of antidiabetics)
- SSRIs (may affect thyroid function tests, rarely requiring dose adjustment)
- Lithium (can cause hypothyroidism)
- Iodine-containing products (can affect thyroid function)
Minor Interactions
- Caffeine (minimal effect on absorption)
Monitoring
Baseline Monitoring
Thyroid Stimulating Hormone (TSH)
Rationale: Primary diagnostic marker for hypothyroidism and to guide initial dosing.
Timing: Before initiating therapy.
Free Thyroxine (Free T4)
Rationale: To assess baseline thyroid hormone levels, especially in central hypothyroidism.
Timing: Before initiating therapy.
Cardiac status (ECG, history of CAD)
Rationale: To assess risk for adverse cardiac events, especially in elderly or patients with pre-existing heart disease, as thyroid hormone replacement can increase cardiac workload.
Timing: Before initiating therapy, particularly in older adults or those with cardiac risk factors.
Routine Monitoring
Thyroid Stimulating Hormone (TSH)
Frequency: Every 4-6 weeks until stable, then every 6-12 months once stable.
Target: 0.4-4.0 mIU/L (for primary hypothyroidism, individualized based on patient factors and guidelines).
Action Threshold: Adjust dose if TSH is outside target range (e.g., >4.0 mIU/L indicates under-replacement, <0.4 mIU/L indicates over-replacement).
Free Thyroxine (Free T4)
Frequency: May be monitored if TSH is suppressed (e.g., central hypothyroidism, thyroid cancer suppression) or if TSH is discordant with clinical picture.
Target: Reference range (e.g., 0.8-1.8 ng/dL), or individualized for specific conditions.
Action Threshold: Adjust dose if Free T4 is outside target range or clinical symptoms persist despite normal TSH.
Clinical symptoms (e.g., fatigue, weight changes, cold intolerance, heart rate)
Frequency: At each visit.
Target: Resolution or improvement of hypothyroid symptoms.
Action Threshold: Persistent or worsening symptoms despite normal TSH may indicate need for further investigation or dose adjustment.
Symptom Monitoring
- Fatigue
- Weight gain or difficulty losing weight
- Cold intolerance
- Constipation
- Dry skin
- Hair loss
- Bradycardia (slow heart rate)
- Muscle aches and weakness
- Depression
- Memory problems
- Hoarseness
- Puffiness in face
- Irritability
- Nervousness
- Palpitations
- Tremor
- Heat intolerance
- Diarrhea
- Insomnia
- Weight loss (unintended)
Special Patient Groups
Pregnancy
Levothyroxine is essential for normal fetal development and is considered safe and necessary during pregnancy. Hypothyroidism during pregnancy can lead to adverse maternal and fetal outcomes. Levothyroxine requirements often increase during pregnancy (by 25-50% or more).
Trimester-Specific Risks:
First Trimester:
Untreated maternal hypothyroidism in the first trimester is associated with increased risk of miscarriage, preterm birth, and impaired neurocognitive development in the offspring.
Second Trimester:
Continued need for adequate thyroid hormone for fetal brain development. Dose adjustments are common.
Third Trimester:
Continued need for adequate thyroid hormone. TSH should be monitored frequently (e.g., every 4-6 weeks) throughout pregnancy.
Lactation
Levothyroxine is compatible with breastfeeding. Only small amounts are excreted into breast milk, which are not clinically significant and do not affect infant thyroid function. It is considered safe for the nursing infant.
Infant Risk:
Low risk. No adverse effects on breastfed infants have been reported.
Pediatric Use
Dosing is weight-based and higher per kg than in adults, especially in neonates and infants, due to rapid growth and development. Close monitoring of TSH and Free T4 is crucial to ensure proper neurocognitive development. Tirosint capsules may be opened and the contents mixed with water or breast milk for easier administration in infants and young children.
Geriatric Use
Elderly patients, especially those with underlying cardiovascular disease, should be started on lower initial doses (e.g., 12.5-25 mcg/day) and titrated slowly to avoid precipitating cardiac events (e.g., angina, arrhythmias). TSH monitoring remains the primary guide for dose adjustment.
Clinical Information
Clinical Pearls
- Tirosint capsules contain levothyroxine in a liquid gel formulation, which may be beneficial for patients with malabsorption issues, gastric pH abnormalities (e.g., on PPIs), or allergies to common excipients (e.g., lactose, gluten) found in tablet formulations.
- Consistency is key: Advise patients to take levothyroxine at the same time each day, ideally 30-60 minutes before breakfast, to maximize absorption and minimize variability.
- Many medications and foods interfere with levothyroxine absorption. Emphasize separating administration by at least 4 hours from calcium, iron, antacids, sucralfate, and bile acid sequestrants.
- Patients often require dose increases during pregnancy. Monitor TSH every 4-6 weeks and adjust dose as needed.
- Symptoms of hypothyroidism resolve slowly. It can take several weeks for patients to feel the full effect of a stable dose.
- Over-replacement can lead to symptoms of hyperthyroidism, bone loss (especially in postmenopausal women), and cardiac arrhythmias (e.g., atrial fibrillation). Under-replacement can lead to persistent hypothyroid symptoms and long-term complications.
- Tirosint-SOL is a liquid formulation available for patients who cannot swallow capsules or require precise dose adjustments (e.g., pediatric patients).
Alternative Therapies
- Liothyronine (T3) - used in specific situations like myxedema coma or for short-term TSH suppression before thyroid cancer scans, but not for routine long-term replacement due to shorter half-life and fluctuating levels.
- Desiccated Thyroid Extract (e.g., Armour Thyroid, Nature-Throid, WP Thyroid) - natural thyroid hormone from porcine glands containing both T4 and T3. Dosing is less precise and potency can vary.
Cost & Coverage
Average Cost:
$30-$100+ per 30 capsules (Tirosint)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (generic levothyroxine), Tier 2 or 3 (Tirosint and other brands)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.