Levothyroxine 0.025mg (25mcg) Caps

Levothyroxine (T4) is a synthetic form of the naturally occurring 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, regulating gene expression and controlling numerous cellular processes involved in metabolism, growth, and development.

Urgent 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 immediately or seek emergency 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, 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. Many people experience no side effects or only 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)

Reporting Side Effects

This is not an exhaustive list of 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 and medications with your doctor.

To ensure your safety, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* 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 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 avoid any potential issues, do not allow your supply of this medication to run out. Please note that it may take several weeks to experience the full effects of this medication.

If you have diabetes (high blood sugar), it is crucial to discuss this 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.

Potential Risks and Side Effects

High doses of this medication may increase the risk of developing weak bones (osteoporosis), particularly after menopause. Consult with your doctor to determine if you are at a higher risk of osteoporosis or if you have any concerns.

This medication may also affect fertility, potentially leading to difficulties in getting pregnant or fathering a child. If you plan to become pregnant or father a child, discuss this with your doctor before starting treatment.

Special Considerations

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

If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor, as they will need to discuss the benefits and risks of this medication with you and determine the best course of action for you and your baby.

Pediatric Patients

If you are giving this medication to a child and their weight changes, 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, so be sure to discuss this with your doctor.

• Amiodarone (can cause hypo- or hyperthyroidism, alters T4 to T3 conversion)
• Oral anticoagulants (e.g., Warfarin - levothyroxine may increase anticoagulant effect)
• Tyrosine kinase inhibitors (e.g., Sunitinib, Imatinib - may increase levothyroxine requirements)
• Ion exchange resins (e.g., Cholestyramine, Colestipol - significantly reduce levothyroxine absorption)
• Sucralfate (reduces levothyroxine absorption)
• Proton pump inhibitors (e.g., Omeprazole - may reduce levothyroxine absorption by increasing gastric pH)
• Antacids (e.g., Aluminum hydroxide, Calcium carbonate - reduce levothyroxine absorption)
• Iron supplements (reduce levothyroxine absorption)
• Soy products (may increase levothyroxine requirements)

• Estrogens (increase TBG, may increase levothyroxine requirements)
• Androgens (decrease TBG, may decrease levothyroxine requirements)
• Glucocorticoids (may decrease TBG, alter T4 to T3 conversion)
• Beta-blockers (e.g., Propranolol - may inhibit T4 to T3 conversion)
• Salicylates (high doses - may inhibit TBG binding)
• Phenytoin, Carbamazepine, Rifampin, Phenobarbital (induce hepatic metabolism of thyroid hormones, increasing levothyroxine requirements)
• Sertraline (may increase levothyroxine requirements)
• Orlistat (may reduce levothyroxine absorption)
• Dietary fiber (may reduce levothyroxine absorption)

• Caffeine (minimal effect on absorption)
• Grapefruit juice (minimal effect on absorption)

• Fatigue
• Weight changes (gain or loss)
• Cold intolerance
• Constipation
• Dry skin
• Hair loss
• Bradycardia
• Muscle aches/weakness
• Depression
• Memory impairment
• Nervousness
• Palpitations
• Tremor
• Heat intolerance
• Diarrhea
• Insomnia

Levothyroxine requirements often increase during pregnancy. It is crucial to continue and adjust therapy to maintain euthyroid state for optimal maternal and fetal outcomes. Untreated maternal hypothyroidism can lead to adverse pregnancy outcomes (e.g., miscarriage, preterm birth, preeclampsia) and impaired neurocognitive development in the child.

Levothyroxine is considered compatible with breastfeeding. Minimal amounts are excreted into breast milk, and it is not expected to cause adverse effects in breastfed infants. It is essential for the mother's health and milk production.

Dosing is weight-based and higher per kg than in adults, especially in infants and young children, due to higher metabolic rates and rapid growth. Close monitoring of TSH and Free T4 is essential to ensure proper growth and neurocognitive development. Adherence is critical.

Lower initial doses (e.g., 12.5-25 mcg/day) are recommended, especially in patients with underlying cardiac disease, due to increased sensitivity to thyroid hormones and potential for cardiac adverse effects. Dose titration should be slower and more cautious. Monitor for signs of cardiac decompensation.

• Levothyroxine is a narrow therapeutic index drug; small dose changes can have significant effects on TSH.
• Consistency is key: Take at the same time each day, on an empty stomach, and separate from interacting medications/foods.
• Capsule formulation (Tirosint) may have more consistent absorption and fewer excipients, potentially beneficial for patients with absorption issues or allergies to tablet excipients.
• Patients should be advised that it may take several weeks to feel the full effects of a dose change.
• Symptoms of over-replacement (hyperthyroidism) can mimic anxiety or cardiac issues; always consider dose reduction if TSH is suppressed.
• Patients with central hypothyroidism (pituitary/hypothalamic dysfunction) should be monitored with Free T4, as TSH may not be a reliable indicator.
• Stress the importance of not switching between different brands or generic formulations without consulting a physician, as bioavailability can vary, potentially requiring dose adjustment.

• Liothyronine (T3) - used less commonly as monotherapy due to shorter half-life and more fluctuating levels, but sometimes used in combination with levothyroxine.

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's a good idea to check with your pharmacist. If you have any questions or concerns about this 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 seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.