Levothyroxine 0.125mg (125mcg) Tabs

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, oxygen consumption, and carbohydrate and lipid metabolism.

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, or 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

Additional Side Effects in Children:

Hip or knee pain
Limping

Additional Side Effects 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 are bothered by any of the following side effects or if they do not go away, contact your doctor:

Hair loss (usually temporary and resolves on its own within the first few months of treatment)

Reporting Side Effects

This is not a comprehensive list of all possible 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.

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, provide your doctor and pharmacist with a comprehensive list of all the medications you are taking, including:
Prescription medications
Over-the-counter (OTC) medications
Natural products
* Vitamins

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 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.

When taking biotin or products containing biotin, discontinue use 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, 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 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.

Special Considerations for Children

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 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.

• Uncorrected adrenal insufficiency (risk of acute adrenal crisis)

• Oral anticoagulants (e.g., Warfarin - increased anticoagulant effect)
• Antidiabetic agents (e.g., Insulin, Metformin - altered glucose control, may require increased antidiabetic dose)
• Bile acid sequestrants (e.g., Cholestyramine, Colestipol - decreased levothyroxine absorption)
• Ion exchange resins (e.g., Sevelamer, Patiromer - decreased levothyroxine absorption)
• Iron supplements (decreased levothyroxine absorption)
• Calcium supplements (decreased levothyroxine absorption)
• Sucralfate (decreased levothyroxine absorption)
• Proton pump inhibitors (e.g., Omeprazole, Pantoprazole - decreased levothyroxine absorption)
• Amiodarone (can cause hypo- or hyperthyroidism, alters T4 to T3 conversion)
• Tyrosine kinase inhibitors (e.g., Imatinib, Sunitinib - can cause hypothyroidism, may increase levothyroxine requirements)

• Phenytoin, Carbamazepine, Rifampin (increase levothyroxine metabolism, may require higher doses)
• Sertraline (may increase levothyroxine requirements)
• Antacids (e.g., Aluminum hydroxide, Magnesium hydroxide - decreased levothyroxine absorption)
• Orlistat (decreased levothyroxine absorption)
• Estrogens (increase TBG, may increase levothyroxine requirements)
• Androgens (decrease TBG, may decrease levothyroxine requirements)

• Not typically categorized as minor for clinically significant drug-drug interactions with levothyroxine.

• Fatigue
• Weight gain
• Constipation
• Cold intolerance
• Dry skin
• Hair loss
• Bradycardia
• Depression
• Muscle aches
• Puffy face
• Hoarseness
• Memory impairment
• Palpitations
• Chest pain
• Shortness of breath
• Excessive sweating
• Tremors
• Nervousness
• Insomnia
• Weight loss (unexplained)
• Diarrhea

Levothyroxine is essential for normal fetal neurological development. Thyroid hormone requirements often increase during pregnancy (by 25-50% or more), especially in the first trimester. Close monitoring of TSH and Free T4 is crucial, and dose adjustments are frequently needed. Untreated maternal hypothyroidism is associated with adverse pregnancy outcomes.

Levothyroxine is compatible with breastfeeding. Minimal amounts are excreted into breast milk, and these amounts are not considered clinically significant to the infant.

Dosing is weight-based and age-dependent. Regular monitoring of TSH, Free T4, and clinical parameters (growth, development, bone age) is essential. Treatment is lifelong for congenital hypothyroidism. Tablets can be crushed and suspended in a small amount of water or breast milk/formula and administered by spoon or dropper.

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

• Levothyroxine should always be taken on an empty stomach, ideally 30-60 minutes before breakfast, to ensure consistent absorption.
• Separate administration from calcium, iron, antacids, and certain other medications by at least 4 hours.
• Do not switch between different generic or brand formulations without consulting a healthcare provider, as bioavailability differences can lead to fluctuations in thyroid hormone levels.
• Full therapeutic effect and TSH stabilization may take 4-6 weeks after a dose change.
• Lifelong therapy is typically required for primary hypothyroidism.
• Patients with pre-existing cardiac disease should be started on lower doses and titrated slowly to avoid exacerbation of cardiac symptoms.

• Liothyronine (T3 - synthetic triiodothyronine)
• Liotrix (combination of T4 and T3)
• Desiccated Thyroid Extract (natural thyroid hormone from animal glands, contains T4 and T3)

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 this 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, including the amount taken and the time it happened, to ensure you receive the best possible care.