Levothyroxine 0.125mg (125mcg) Caps

Levothyroxine (T4) is a synthetic form of the natural thyroid hormone, thyroxine. It is converted to its active metabolite, liothyronine (T3), in peripheral tissues. T3 then enters the cell nucleus and binds to thyroid hormone receptors, which in turn bind to specific DNA sequences (thyroid hormone response elements) to regulate gene expression. This process controls metabolism, growth, and development.

Serious Side Effects: Seek Medical Help Right Away

While rare, some people may experience severe and potentially life-threatening side effects when 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
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 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. Many people experience no side effects or only mild ones. If you're bothered by any of the following side effects or if they don't go away, contact your doctor:

Hair loss (usually temporary and resolves on its own)
Other side effects not listed here

If you have questions or concerns about side effects, talk to your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

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 with your doctor.

Additionally, to ensure safe treatment, tell your doctor and pharmacist about:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
All your health problems

It is vital to verify that it is safe to take this medication with all your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.

Important Information for 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 run out of this medication, as it may take several weeks to experience its full effects.

Special Considerations

If you have diabetes (high blood sugar), consult your doctor, as this medication may affect 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.
If you take biotin or products containing biotin, stop taking it at least 2 days before having your thyroid levels checked.
High doses of this medication may increase the risk of osteoporosis (weak bones), particularly after menopause. Discuss your risk factors with your doctor and address any concerns you may have.
This medication may affect fertility, potentially leading to difficulty getting pregnant or fathering a child. If you plan to conceive, consult your doctor before starting treatment.
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects.

Pregnancy, Breastfeeding, and Pediatric Use

If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor to discuss the benefits and risks to you and your baby.
When giving this medication to a child, monitor their weight changes and consult your doctor, as the dosage may need to be adjusted. Never exceed the prescribed dose, as this may 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 this further.

• Amiodarone (can alter thyroid function and metabolism of levothyroxine)
• Warfarin (levothyroxine can enhance anticoagulant effect, requiring warfarin dose reduction)
• Tyrosine kinase inhibitors (e.g., imatinib, sunitinib, sorafenib, pazopanib - can decrease levothyroxine absorption or increase metabolism)
• Orlistat (can significantly decrease levothyroxine absorption)
• Sevelamer (can decrease levothyroxine absorption)

• Antacids (aluminum, magnesium, calcium carbonate - decrease absorption; separate by 4 hours)
• Iron supplements (decrease absorption; separate by 4 hours)
• Calcium supplements (decrease absorption; separate by 4 hours)
• Bile acid sequestrants (cholestyramine, colestipol - decrease absorption; separate by 4-6 hours)
• Proton pump inhibitors (e.g., omeprazole, lansoprazole - may increase gastric pH, reducing absorption; monitor TSH)
• Sucralfate (decreases absorption; separate by 4 hours)
• Soy products (can decrease absorption; monitor TSH)
• Dietary fiber (can decrease absorption; monitor TSH)
• Certain antidepressants (e.g., sertraline - may increase levothyroxine requirements)
• Estrogens/Oral Contraceptives (increase TBG, increasing levothyroxine requirements)
• Androgens/Anabolic steroids (decrease TBG, decreasing levothyroxine requirements)
• Phenytoin, Carbamazepine, Rifampin, Phenobarbital (induce hepatic enzymes, increasing levothyroxine metabolism; may require dose increase)
• Beta-blockers (e.g., propranolol - may inhibit peripheral conversion of T4 to T3)
• Corticosteroids (may inhibit peripheral conversion of T4 to T3)
• Insulin/Oral Hypoglycemics (levothyroxine may increase blood glucose, requiring adjustment of antidiabetic agents)

• Coffee (may decrease absorption; take levothyroxine at least 30-60 minutes before coffee)

• Symptoms of hypothyroidism (e.g., fatigue, weight gain, constipation, cold intolerance, dry skin, hair loss, depression, bradycardia)
• Symptoms of hyperthyroidism (e.g., palpitations, nervousness, tremor, weight loss, heat intolerance, diarrhea, insomnia, tachycardia)

Levothyroxine is safe and essential during pregnancy. Thyroid hormone requirements often increase during pregnancy (by 25-50% or more) due to increased TBG, placental deiodination, and fetal thyroid hormone needs. Close monitoring of TSH (every 4-6 weeks) and dose adjustment are crucial to maintain maternal euthyroidism for optimal fetal development.

Levothyroxine is considered safe during breastfeeding. Only small amounts are excreted into breast milk, and these amounts are not sufficient to cause adverse effects in the infant or affect infant thyroid function.

Dosing is weight-based and critical for normal growth and neurocognitive development. Under-treatment can lead to irreversible intellectual disability and growth retardation. Over-treatment can lead to craniosynostosis in infants and accelerated bone maturation. Close monitoring of TSH and free T4 is essential.

Older patients may require lower starting doses and more gradual titration due to increased sensitivity to thyroid hormones and a higher prevalence of underlying cardiovascular disease. Monitor for cardiac symptoms (e.g., angina, arrhythmias).

• Always take levothyroxine on an empty stomach, 30-60 minutes before breakfast, with water, and separate from other medications and supplements (especially calcium, iron, antacids) by at least 4 hours.
• Consistency is key: take it at the same time each day.
• Do not switch between different brands or formulations (e.g., tablet vs. capsule) without consulting your doctor, as bioavailability can vary, requiring dose adjustments.
• TSH is the primary lab test for monitoring, but Free T4 may also be useful in certain situations (e.g., central hypothyroidism, TSH suppression therapy).
• Clinical response is gradual; it takes weeks for symptoms to improve and TSH to stabilize.
• Patients with cardiovascular disease should start with lower doses and titrate slowly to avoid exacerbating cardiac symptoms.
• Pregnancy significantly increases levothyroxine requirements; monitor TSH frequently (every 4-6 weeks) and adjust dose as needed.

• Liothyronine (T3, Cytomel): Used in specific cases, often for short-term TSH suppression or in combination with levothyroxine.
• Desiccated Thyroid Extract (Armour Thyroid, NP Thyroid): Natural thyroid hormone derived from porcine thyroid glands, containing both T4 and T3. Dosing can be less precise due to variable T4/T3 ratios.
• Levothyroxine/Liothyronine combination products (e.g., Thyrolar): Synthetic combination of T4 and T3.

If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist. If you have any questions or concerns about your medication, don't hesitate to discuss them with 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 reporting the incident, be prepared to provide detailed information, including the name of the medication taken, the amount, and the time it occurred.