Levothyroxine 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 then binds 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.

Serious Side Effects: Seek Medical Help 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 attention 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, 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

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 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 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 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 as advised.

If you take biotin or products 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 osteoporosis (weak bones), 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.

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

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 weight changes, consult your doctor, as the dosage may need to be adjusted. Never give your child more than 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 any concerns.

• Bile acid sequestrants (e.g., cholestyramine, colestipol): Reduce levothyroxine absorption.
• Ion exchange resins (e.g., sevelamer, patiromer): Reduce levothyroxine absorption.
• Sucralfate: Reduces levothyroxine absorption.
• Iron supplements: Reduce levothyroxine absorption.
• Calcium supplements: Reduce levothyroxine absorption.
• Antacids (aluminum, magnesium, simethicone): Reduce levothyroxine absorption.
• Proton pump inhibitors (e.g., omeprazole): May reduce levothyroxine absorption.
• H2 receptor blockers (e.g., cimetidine): May reduce levothyroxine absorption.
• Orlistat: May reduce levothyroxine absorption.
• Phenytoin, Carbamazepine, Rifampin, Phenobarbital: Increase levothyroxine metabolism.
• Amiodarone: Can cause hypo- or hyperthyroidism, and alter T4 to T3 conversion.
• Warfarin: Levothyroxine may potentiate anticoagulant effects, increasing bleeding risk.
• Antidiabetic agents (insulin, oral hypoglycemics): Levothyroxine may increase blood glucose, requiring increased antidiabetic dose.

• Soy products: May decrease levothyroxine absorption.
• Dietary fiber: May decrease levothyroxine absorption.
• Grapefruit juice: May decrease levothyroxine absorption.
• Estrogens (oral): Increase TBG, potentially increasing levothyroxine requirements.
• Androgens: Decrease TBG, potentially decreasing levothyroxine requirements.
• Beta-blockers: May decrease conversion of T4 to T3.
• Tricyclic antidepressants: Increased sensitivity to TCAs, increased risk of arrhythmias.
• Digitalis glycosides: Decreased therapeutic effect of digitalis.

• Caffeine: No significant interaction, but some patients report increased anxiety.

• Fatigue
• Weight changes (gain or loss)
• Cold intolerance
• Constipation
• Dry skin
• Hair loss
• Bradycardia
• Depression
• Memory impairment
• Muscle aches
• Menstrual irregularities

Levothyroxine is Category A and is safe and essential during pregnancy. Thyroid hormone requirements often increase during pregnancy (by 25-50% or more) due to increased TBG and fetal needs. Close monitoring of TSH (every 4-6 weeks) is crucial.

Levothyroxine is compatible with breastfeeding (L1). Only small amounts are excreted into breast milk, which are not clinically significant to the infant.

Dosing is weight-based and higher per kg than in adults, especially in neonates and infants, due to rapid growth and development. Regular monitoring of TSH and Free T4 is essential to ensure proper growth and neurocognitive development. Under-treatment can lead to irreversible intellectual disability.

Lower initial 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 risk of cardiac adverse effects. Dose titration should be slower and more cautious. Monitor for cardiac symptoms.

• Take levothyroxine consistently at the same time each day, preferably 30-60 minutes before breakfast, with water, to maximize absorption.
• Separate administration from calcium, iron, antacids, and other interacting medications by at least 4 hours.
• Do not switch between different brands or generic formulations without consulting a healthcare provider, as bioequivalence can vary and may require dose adjustment.
• Patients with central hypothyroidism (pituitary/hypothalamic dysfunction) should be monitored with Free T4 levels, as TSH may not be a reliable indicator.
• Symptoms of over- or under-treatment can mimic other conditions; always correlate with TSH and Free T4 levels.
• Weight loss is NOT an indication for levothyroxine in euthyroid individuals and can be dangerous.

• Liothyronine (T3) - used in specific situations like myxedema coma or for short-term TSH suppression before radioactive iodine.
• Desiccated thyroid extract (e.g., Armour Thyroid, Nature-Throid) - contains both T4 and T3, derived from porcine thyroid glands.

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.