Levothyroxine 0.175mg (175mcg) 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 regulate gene expression and control various metabolic processes, including protein synthesis, carbohydrate metabolism, lipid metabolism, and cellular respiration. It is essential for normal growth, development, and metabolism.

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
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 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)

Reporting Side Effects

This list is not exhaustive, and you may experience other side effects not mentioned here. 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 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 using it at least 2 days before having your thyroid levels checked to ensure accurate test results.

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 of developing osteoporosis.

This medication may affect fertility, making it more difficult to become pregnant or father a child. If you plan to conceive, consult with 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 and Breastfeeding

If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to you and your baby.

Special Considerations for Children

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 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 with your doctor to discuss any concerns.

• Antacids (aluminum, magnesium, calcium carbonate): Decrease levothyroxine absorption.
• Iron supplements: Decrease levothyroxine absorption.
• Calcium supplements: Decrease levothyroxine absorption.
• Sucralfate: Decreases levothyroxine absorption.
• Bile acid sequestrants (cholestyramine, colestipol): Decrease levothyroxine absorption.
• Proton pump inhibitors (PPIs) and H2 blockers: May decrease levothyroxine absorption by increasing gastric pH.
• Orlistat: May decrease levothyroxine absorption.
• Soy products: May decrease levothyroxine absorption.
• Phenytoin, Carbamazepine, Rifampin, Phenobarbital: Increase levothyroxine metabolism, potentially increasing dose requirements.
• Amiodarone: Can cause hypo- or hyperthyroidism; affects T4 to T3 conversion.
• Oral anticoagulants (e.g., Warfarin): Levothyroxine may increase the anticoagulant effect, requiring reduced anticoagulant dose.
• Insulin and oral hypoglycemics: Levothyroxine may increase blood glucose levels, requiring increased antidiabetic medication dose.
• Tyrosine kinase inhibitors (e.g., Sunitinib, Imatinib): May increase levothyroxine requirements.
• Estrogens (oral): Increase TBG, potentially increasing levothyroxine requirements.

• Beta-blockers (e.g., Propranolol): May decrease conversion of T4 to T3.
• Sertraline: May increase levothyroxine requirements.
• Corticosteroids: May decrease TSH secretion and T4 to T3 conversion.
• Salicylates (>2g/day): May inhibit binding of T4 to TBG, increasing free T4.
• Furosemide (>80mg IV): May inhibit binding of T4 to TBG, increasing free T4.
• Lithium: Can cause hypothyroidism.

• Dietary fiber: May slightly decrease absorption.

• Hypothyroid symptoms: Fatigue, weight gain, constipation, cold intolerance, dry skin, hair loss, bradycardia, depression, muscle aches, menstrual irregularities.
• Hyperthyroid symptoms (due to over-replacement): Palpitations, tachycardia, nervousness, tremors, weight loss, heat intolerance, diarrhea, insomnia, sweating.

Levothyroxine is Category A and is safe and essential during pregnancy. Thyroid hormone requirements often increase during pregnancy, especially in the second and third trimesters. Close monitoring of TSH levels is crucial, and dose adjustments are frequently needed.

Levothyroxine is considered safe during breastfeeding (L1). Minimal amounts are excreted into breast milk, and it does not adversely affect the infant. It is essential for maternal health and does not interfere with lactation.

Dosing is weight-based and higher per kg than in adults, especially in neonates and infants, due to higher metabolic rates and rapid growth. Close monitoring of TSH and T4 is essential for proper growth and neurodevelopment. Capsules may be opened and mixed with a small amount of water or breast milk for administration to infants/young children.

Lower starting doses (e.g., 12.5-25 mcg/day) are often recommended due to increased sensitivity to thyroid hormones and a higher prevalence of underlying cardiovascular disease. Dose adjustments should be made cautiously and gradually, with careful monitoring of TSH and cardiac status.

• Administer levothyroxine consistently, preferably in the morning on an empty stomach, 30-60 minutes before food or other medications, to optimize absorption.
• Many medications and foods can interfere with levothyroxine absorption; advise patients to separate administration times.
• The full therapeutic effect of a dose change may not be seen for 4-6 weeks due to the long half-life of levothyroxine.
• TSH is the primary laboratory test for monitoring levothyroxine therapy in primary hypothyroidism.
• Patients with pre-existing cardiovascular disease should be started on lower doses and titrated slowly to avoid exacerbating cardiac symptoms.
• Levothyroxine is not for weight loss in euthyroid individuals and can cause serious adverse effects if misused for this purpose.

• Liothyronine (T3, Cytomel): Used less commonly as monotherapy due to shorter half-life and more fluctuating levels, but sometimes used in combination with levothyroxine.
• Desiccated Thyroid Extract (Armour Thyroid, NP Thyroid): Natural thyroid hormone preparation containing both T4 and T3, derived from porcine thyroid glands. Dosing can be less precise due to variable hormone content.

If your symptoms or health issues persist or worsen, it is 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 it is a good idea to consult with your pharmacist. If you have any questions or concerns about this medication, do not 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 seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.