Levothyroxine 0.075mg (75mcg) Caps
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 hormone replacement; Synthetic L-thyroxine
Pregnancy Category
A
FDA Approved
Aug 2007
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's metabolism work properly, reducing symptoms like tiredness, weight gain, and feeling cold.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. 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, inform your doctor.
Important Notes
There are different brands and forms of this medication. Do not switch between them without consulting your doctor.
Continue taking your medication as directed by your doctor or healthcare provider, even if you feel well.
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.
Missing 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 get the most benefit from your medication, follow your doctor's instructions carefully. 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, inform your doctor.
Important Notes
There are different brands and forms of this medication. Do not switch between them without consulting your doctor.
Continue taking your medication as directed by your doctor or healthcare provider, even if you feel well.
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.
Missing 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, preferably 30-60 minutes before breakfast, with a full glass of water.
- Take at the same time each day to maintain consistent levels.
- Do not take with other medications, vitamins, or supplements (especially iron, calcium, antacids) within 4 hours of your levothyroxine dose.
- Avoid switching between different brands or formulations of levothyroxine without consulting your doctor, as they may not be bioequivalent.
- Inform your doctor about all other medications, supplements, and herbal products you are taking.
Available Forms & Alternatives
Available Strengths:
- Levothyroxine 0.100mg(100mcg) Tab
- Levothyroxine 0.075mg (75mcg) Tabs
- Levothyroxine 0.125mg (125mcg) Tab
- Levothyroxine 0.05mg (50mcg) Tab
- Levothyroxine 0.025mg (25mcg) Tab
- Levothyroxine 0.112mg (112mcg) Tabs
- Levothyroxine 0.137mg (137mcg) Tab
- Levothyroxine 0.175mg (175mcg) Tabs
- Levothyroxine 500mcg Inj, 1 Vial
- Levothyroxine Sod 100mcg Inj, 1vial
- Levothyroxine 200mcg Inj, 1 Vial
- Levothyroxine 0.088mg (88mcg) Tab
- Levothyroxine 0.100mg (100mcg) Tab
- Levothyroxine 0.150mg (150mcg) Tab
- Levothyroxine 0.2mg (200mcg) Tab
- Levothyroxine 0.3mg (300mcg) Tab
- Levothyroxine 0.013mg (13mcg) Caps
- Levothyroxine 0.025mg (25mcg) Caps
- Levothyroxine 0.05mg (50mcg) Caps
- Levothyroxine 0.075mg (75mcg) Caps
- Levothyroxine 0.088mg (88mcg) Caps
- Levothyroxine 0.100mg (100mcg) Caps
- Levothyroxine 0.112mg (112mcg) Caps
- Levothyroxine 0.125mg (125mcg) Caps
- Levothyroxine 0.137mg (137mcg) Caps
- Levothyroxine 0.150mg (150mcg) Caps
- Levothyroxine 0.175mg (175mcg) Caps
- Levothyroxine 0.2mg (200mcg) Caps
- Levothyroxine 0.125mg (125mcg) Tabs
- Levothyroxine 100mcg/5ml Inj, 5ml
- Levothyroxine 100mcg/ml Inj, 1ml
- Levothyroxine 500mg/5ml Inj, 5ml
- Levothyroxine 200mcg/5ml Inj, 5ml
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 1.6 mcg/kg/day orally once daily for primary hypothyroidism. Average full replacement dose: 100-125 mcg/day.
Dose Range:
25 - 300 mg
Condition-Specific Dosing:
primaryHypothyroidism:
Initial: 1.6 mcg/kg/day. Adjust by 12.5-25 mcg increments every 4-6 weeks based on TSH. Elderly or cardiac patients: Initial 12.5-25 mcg/day, titrate slowly.
subclinicalHypothyroidism:
Initial: 25-75 mcg/day, titrate based on TSH.
thyroidStimulatingHormoneSuppression:
Higher doses (e.g., 2-2.5 mcg/kg/day) for thyroid cancer suppression, adjusted based on TSH target.
Pediatric Dosing
Neonatal:
Initial: 10-15 mcg/kg/day orally once daily (for congenital hypothyroidism).
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.
Child:
1-5 years: 5-6 mcg/kg/day; 6-12 years: 4-5 mcg/kg/day.
Adolescent:
12 years and older (growth and puberty complete): 2-3 mcg/kg/day or adult dose (1.6 mcg/kg/day).
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed.
Moderate:
No adjustment needed.
Severe:
No adjustment needed, but monitor thyroid function closely.
Dialysis:
No adjustment needed; not significantly removed by dialysis.
Hepatic Impairment:
Mild:
No adjustment needed.
Moderate:
No adjustment needed.
Severe:
No specific adjustment, but monitor thyroid function closely as metabolism may be altered.
Pharmacology
Mechanism of Action
Levothyroxine (L-thyroxine) is a synthetic form of the natural thyroid hormone, thyroxine (T4). It is converted to its active metabolite, liothyronine (T3), in peripheral tissues. T3 then enters the cell nucleus and binds to thyroid hormone receptors, regulating gene expression and controlling numerous metabolic processes, including protein, carbohydrate, and lipid metabolism, and influencing growth and development.
Pharmacokinetics
Absorption:
Bioavailability:
48-80% (variable, affected by food and other drugs)
Tmax:
2-4 hours
FoodEffect:
Decreased absorption when taken with food, certain foods (e.g., soy formula, fiber) and supplements (e.g., iron, calcium) can significantly reduce absorption.
Distribution:
Vd:
10-13 L
ProteinBinding:
>99% (primarily to thyroxine-binding globulin (TBG), transthyretin, and albumin)
CnssPenetration:
Limited (primarily as T3 after conversion)
Elimination:
HalfLife:
6-7 days (euthyroid); 9-10 days (hypothyroid); 3-4 days (hyperthyroid)
Clearance:
Approximately 0.05 L/hour
ExcretionRoute:
Primarily renal (approximately 80% as metabolites), with some fecal excretion (approximately 20%).
Unchanged:
Approximately 20% of T4 is excreted unchanged in urine and feces.
Pharmacodynamics
OnsetOfAction:
Gradual, clinical effects typically seen within 3-5 days, full therapeutic effect may take 4-6 weeks.
PeakEffect:
Peak TSH suppression/normalization typically occurs within 4-6 weeks of stable dosing.
DurationOfAction:
Due to long half-life, effects persist for several weeks after discontinuation.
Safety & Warnings
Side Effects
Serious Side Effects: Seek Medical Attention Immediately
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 medical help right away:
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
Vomiting
Mood changes, such as:
+ Irritability
+ Nervousness
+ Excitability
+ Anxiety
Shakiness
Trouble sleeping
Sensitivity to heat
Excessive sweating
Fever
Muscle cramps
Muscle weakness
Flushing
Bone pain
Changes in menstrual periods
Additional Side Effects in Children and Infants
Children: Hip or knee pain, or a limp
Infants: Changes in the shape of the head and face
Other Possible Side Effects
Not everyone experiences side effects, and many people have only minor side effects. However, if you notice 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)
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 medical help right away:
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
Vomiting
Mood changes, such as:
+ Irritability
+ Nervousness
+ Excitability
+ Anxiety
Shakiness
Trouble sleeping
Sensitivity to heat
Excessive sweating
Fever
Muscle cramps
Muscle weakness
Flushing
Bone pain
Changes in menstrual periods
Additional Side Effects in Children and Infants
Children: Hip or knee pain, or a limp
Infants: Changes in the shape of the head and face
Other Possible Side Effects
Not everyone experiences side effects, and many people have only minor side effects. However, if you notice 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)
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:
- **Symptoms of too much thyroid hormone (hyperthyroidism):** Fast or irregular heartbeat, chest pain, shortness of breath, nervousness, irritability, sweating, heat intolerance, unexplained weight loss, diarrhea, tremor, insomnia.
- **Symptoms of too little thyroid hormone (hypothyroidism - if dose is too low or missed):** Extreme tiredness, weight gain, constipation, dry skin, hair loss, feeling cold, depression, muscle aches, memory problems.
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 allergic reaction you experienced, including any symptoms that occurred.
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 and medications with your doctor.
To ensure your safety, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your health problems
Carefully review your medications and health conditions with your doctor to confirm that it is safe to take this medication. Never start, stop, or adjust 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 allergic reaction you experienced, including any symptoms that occurred.
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 and medications with your doctor.
To ensure your safety, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your health problems
Carefully review your medications and health conditions with your doctor to confirm that it is safe to take this medication. Never start, stop, or adjust 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 continuous treatment, do not allow your supply of this medication to run out. You may not experience the full effects of this medication for several weeks.
If you have diabetes (high blood sugar), consult your doctor, as this medication may affect your blood sugar control. Your doctor may need to adjust your diabetes medications. Monitor your blood sugar levels as directed by your doctor and undergo regular blood tests as advised.
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 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 in getting pregnant or fathering a child. If you plan to conceive, consult your doctor before starting treatment.
Special Precautions
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
Inform your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. Your doctor will discuss the benefits and risks of this medication for you and your baby.
Pediatric Patients
If your child is taking this medication and experiences any weight changes, consult your doctor, as their dose 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. Consult your doctor to discuss any concerns.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. To ensure continuous treatment, do not allow your supply of this medication to run out. You may not experience the full effects of this medication for several weeks.
If you have diabetes (high blood sugar), consult your doctor, as this medication may affect your blood sugar control. Your doctor may need to adjust your diabetes medications. Monitor your blood sugar levels as directed by your doctor and undergo regular blood tests as advised.
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 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 in getting pregnant or fathering a child. If you plan to conceive, consult your doctor before starting treatment.
Special Precautions
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
Inform your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. Your doctor will discuss the benefits and risks of this medication for you and your baby.
Pediatric Patients
If your child is taking this medication and experiences any weight changes, consult your doctor, as their dose 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. Consult your doctor to discuss any concerns.
Overdose Information
Overdose Symptoms:
- Palpitations
- Tachycardia
- Arrhythmias
- Chest pain (angina)
- Tremor
- Nervousness
- Insomnia
- Diarrhea
- Weight loss
- Fever
- Heat intolerance
- Seizures (rare)
- Coma (rare)
What to Do:
Seek immediate medical attention or call Poison Control at 1-800-222-1222. Treatment is supportive and may include beta-blockers for cardiovascular symptoms, and measures to reduce absorption if recent ingestion.
Drug Interactions
Major Interactions
- Amiodarone (alters thyroid hormone metabolism)
- Warfarin (enhances anticoagulant effect)
- Tyrosine kinase inhibitors (e.g., imatinib, sunitinib, sorafenib - may decrease levothyroxine efficacy)
- Orlistat (may decrease levothyroxine absorption)
Moderate Interactions
- Antacids (aluminum, magnesium, calcium - decrease absorption)
- Iron supplements (decrease absorption)
- Calcium supplements (decrease absorption)
- Bile acid sequestrants (e.g., cholestyramine, colestipol - decrease absorption)
- Proton pump inhibitors (e.g., omeprazole - may decrease absorption due to altered gastric pH)
- Sucralfate (decreases absorption)
- Soy products (decrease absorption)
- Rifampin (increases levothyroxine metabolism)
- Phenytoin (increases levothyroxine metabolism, displaces from protein binding)
- Carbamazepine (increases levothyroxine metabolism)
- Sertraline (may increase levothyroxine requirements)
- Estrogens (increase TBG, increasing levothyroxine requirements)
- Androgens (decrease TBG, decreasing levothyroxine requirements)
- Beta-blockers (may inhibit T4 to T3 conversion)
- Corticosteroids (may inhibit T4 to T3 conversion)
Minor Interactions
- Dietary fiber (may decrease absorption)
Monitoring
Baseline Monitoring
Thyroid-stimulating hormone (TSH)
Rationale: To confirm diagnosis of hypothyroidism and establish baseline for treatment.
Timing: Prior to initiation of therapy.
Free Thyroxine (Free T4)
Rationale: To assess baseline thyroid hormone levels, especially in central hypothyroidism.
Timing: Prior to initiation of therapy.
Clinical symptoms of hypothyroidism
Rationale: To establish baseline symptom severity and monitor response to treatment.
Timing: Prior to initiation of therapy.
Routine Monitoring
Thyroid-stimulating hormone (TSH)
Frequency: Every 4-6 weeks after initiation or dose change, then every 6-12 months once stable.
Target: Typically 0.4-4.0 mIU/L (individualized based on patient factors and etiology).
Action Threshold: Adjust dose if TSH is outside target range (too high indicates under-replacement, too low indicates over-replacement).
Free Thyroxine (Free T4)
Frequency: May be monitored periodically, especially if TSH is not reliable (e.g., central hypothyroidism) or if symptoms persist despite normal TSH.
Target: Typically 0.8-1.8 ng/dL (individualized).
Action Threshold: Adjust dose if Free T4 is consistently outside target range.
Clinical symptoms of hypo/hyperthyroidism
Frequency: At every clinical visit.
Target: Resolution of hypothyroid symptoms, absence of hyperthyroid symptoms.
Action Threshold: Investigate persistent symptoms; consider dose adjustment or alternative diagnoses.
Symptom Monitoring
- Fatigue
- Weight gain
- Cold intolerance
- Constipation
- Dry skin
- Hair loss
- Bradycardia
- Depression
- Muscle aches
- Memory impairment
- Nervousness
- Irritability
- Heat intolerance
- Weight loss (unexplained)
- Palpitations
- Tachycardia
- Tremor
- Diarrhea
- Insomnia
Special Patient Groups
Pregnancy
Levothyroxine requirements often increase during pregnancy. It is crucial to continue therapy and monitor TSH levels closely (every 4-6 weeks) to ensure adequate thyroid hormone replacement for both maternal and fetal health. Untreated hypothyroidism during pregnancy can lead to adverse outcomes for both mother and baby.
Trimester-Specific Risks:
First Trimester:
Increased levothyroxine dose often needed early in pregnancy. Untreated maternal hypothyroidism in the first trimester is associated with impaired neurocognitive development in the fetus.
Second Trimester:
Continued monitoring and dose adjustment as needed.
Third Trimester:
Continued monitoring and dose adjustment as needed. Maternal hypothyroidism can lead to preeclampsia, gestational hypertension, placental abruption, and preterm delivery.
Lactation
Levothyroxine is considered compatible with breastfeeding. Only small amounts are excreted into breast milk, and it is not expected to cause adverse effects in breastfed infants. Maternal thyroid function should be monitored to ensure adequate replacement.
Infant Risk:
Low risk.
Pediatric Use
Dosing is weight-based and higher per kg in younger children due to higher metabolic rates. Regular monitoring of TSH and Free T4 is essential, especially in infants with congenital hypothyroidism, to ensure normal growth and neurocognitive development. Adherence is critical.
Geriatric Use
Lower starting doses (e.g., 12.5-25 mcg/day) are recommended, especially in patients with underlying cardiovascular disease, due to increased sensitivity to thyroid hormones and potential for cardiac adverse effects. Titrate slowly with careful monitoring of TSH and cardiac status.
Clinical Information
Clinical Pearls
- Always take levothyroxine on an empty stomach, 30-60 minutes before breakfast, with water, and separate from other medications and supplements by at least 4 hours.
- Consistency is key: take it at the same time every day.
- Do not switch between different brands or formulations (e.g., tablet to capsule) without consulting your doctor, as bioavailability can vary.
- TSH is the primary lab test for monitoring, but Free T4 may also be used, especially in central hypothyroidism or if TSH is unreliable.
- Full therapeutic effect may take 4-6 weeks, so dose adjustments should not be made more frequently than every 4-6 weeks.
- Patients with cardiac disease should start on lower doses and titrate very slowly to avoid precipitating angina or arrhythmias.
- Symptoms of over-replacement (hyperthyroidism) can include palpitations, nervousness, and weight loss. Symptoms of under-replacement (hypothyroidism) include fatigue, weight gain, and cold intolerance.
Alternative Therapies
- Liothyronine (T3) - used in specific cases, e.g., myxedema coma, or for short-term TSH suppression before radioactive iodine therapy.
Cost & Coverage
Average Cost:
$10 - $50 per 30 capsules (75mcg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Generic) or Tier 2 (Brand)
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 medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.