Euthyrox 0.025mg (25mcg) Tab

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 and T4 act on thyroid hormone receptors in the cell nucleus to regulate gene expression, controlling metabolism, growth, and development.

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 feeling irritable, nervous, excitable, or anxious
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 may not experience any side effects or may only have mild ones. 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 within the first few months of treatment)

This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult 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 and medications with your doctor.

To ensure your safety, 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

Before starting, stopping, or changing the dose of any medication, including this one, consult with your doctor to confirm it is safe for you to do so.

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 with your doctor, as this medication may affect your 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 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 this medication.

Special Considerations

If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects.

If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor, who 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 a change in weight, consult with your doctor, as the dosage may need to be adjusted. Never give your child more of this medication than prescribed, 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, so be sure to discuss this with your doctor.

• Amiodarone (can cause hypo- or hyperthyroidism, affecting levothyroxine dose)
• Warfarin (levothyroxine can increase anticoagulant effect, requiring warfarin dose reduction)
• Tyrosine kinase inhibitors (e.g., imatinib, sunitinib, sorafenib - can reduce levothyroxine absorption or increase metabolism)
• Orlistat (can reduce levothyroxine absorption)

• Antacids (aluminum, magnesium, calcium) - reduce absorption
• Iron supplements - reduce absorption
• Calcium supplements - reduce absorption
• Bile acid sequestrants (cholestyramine, colestipol) - reduce absorption
• Sucralfate - reduce absorption
• Proton pump inhibitors (PPIs) - may reduce absorption due to altered gastric pH
• H2 blockers - may reduce absorption due to altered gastric pH
• Soy products - reduce absorption
• Grapefruit juice - may reduce absorption
• Rifampin, Carbamazepine, Phenytoin, Phenobarbital (enzyme inducers) - increase levothyroxine metabolism, requiring higher doses
• Estrogens (oral) - increase TBG, requiring higher levothyroxine doses
• Androgens - decrease TBG, potentially requiring lower levothyroxine doses
• Beta-blockers (e.g., propranolol) - may inhibit peripheral conversion of T4 to T3
• Corticosteroids - may inhibit peripheral conversion of T4 to T3
• Digoxin - levothyroxine may decrease digoxin levels
• Insulin/Oral Hypoglycemics - levothyroxine may increase blood glucose, requiring adjustment of antidiabetic agents

• Dietary fiber - may reduce absorption

• Symptoms of hypothyroidism (under-replacement): fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss, depression, bradycardia, muscle aches.
• Symptoms of hyperthyroidism (over-replacement): palpitations, tachycardia, anxiety, irritability, weight loss, heat intolerance, tremor, diarrhea, insomnia, sweating.

Levothyroxine is Category A and is essential for fetal neurological development. Thyroid hormone requirements often increase during pregnancy (by 25-50% or more). Regular TSH monitoring is crucial.

Levothyroxine is compatible with breastfeeding. Only small amounts are excreted into breast milk, which are not clinically significant to the infant.

Dosing is weight-based and critical for normal growth and neurological development. Under-treatment can lead to irreversible cognitive impairment (cretinism) if not treated early in infancy. Over-treatment can lead to craniosynostosis in infants and accelerated bone maturation in children.

Lower starting doses (e.g., 12.5-25 mcg/day) are often recommended due to increased risk of cardiac adverse effects (e.g., atrial fibrillation, angina) and potential for subclinical hyperthyroidism. Slower titration is advised. TSH target range may be slightly higher (e.g., 4-6 mIU/L) in very elderly patients.

• Consistency is key: Take levothyroxine at the same time each day, preferably in the morning, on an empty stomach, 30-60 minutes before food or other medications.
• Separate from interacting medications: Ensure a 4-hour separation from calcium, iron, antacids, sucralfate, bile acid sequestrants, and other interacting drugs.
• Brand consistency: While generic levothyroxine is available, some patients may experience subtle differences in efficacy or side effects when switching between brands or generic manufacturers due to slight variations in bioavailability. If a patient is stable on one brand, it's often recommended to stick with it.
• Lifelong therapy: Most patients with hypothyroidism will require lifelong levothyroxine replacement.
• Symptoms vs. Labs: While TSH is the primary monitoring tool, always consider the patient's clinical symptoms. Some patients may feel better with TSH at the lower end of the normal range.
• Pregnancy: Thyroid hormone requirements increase significantly during pregnancy. Monitor TSH every 4-6 weeks and adjust dose as needed.
• Acute illness/Surgery: Levothyroxine dose may need adjustment during acute illness, surgery, or changes in other medications.

• None for primary hypothyroidism (levothyroxine is the standard of care).

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.