Thyroid Np 0.5gr (30mg) Tablets
WARNING: Do not use this drug for weight loss. Severe and sometimes deadly side effects may happen with this drug if it is taken in large doses or with other drugs for weight loss. If you have questions, talk with the doctor. @ COMMON USES: It is used to add thyroid hormone to the body.It is used to treat or prevent an enlarged thyroid.It is used to manage thyroid cancer.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Thyroid hormone replacement
Pharmacologic Class
Thyroid hormones (T3 and T4)
Pregnancy Category
Category A
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
This medication is a natural thyroid hormone replacement. It contains both T3 and T4 hormones, which are normally made by your thyroid gland. It's used to treat an underactive thyroid (hypothyroidism) to help your body's metabolism work properly.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. It's best to take this medication on an empty stomach.
Important Notes About Different Brands and Forms
There are various brands and forms of this medication available. Do not switch between different brands or forms without first consulting your doctor.
Interactions with Other Medications and Foods
Do not take colesevelam, colestipol, or cholestyramine within 4 hours before or 4 hours after taking this medication. Additionally, certain foods like soybean flour (found in infant formula) may affect how this medication works in your body. Discuss this with your doctor.
Establishing a Routine
Take your medication at the same time every day. Continue taking your medication as directed by your doctor or healthcare provider, even if you're feeling well.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of your medication, consult your pharmacist. You may also want to check if there are drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. It's best to take this medication on an empty stomach.
Important Notes About Different Brands and Forms
There are various brands and forms of this medication available. Do not switch between different brands or forms without first consulting your doctor.
Interactions with Other Medications and Foods
Do not take colesevelam, colestipol, or cholestyramine within 4 hours before or 4 hours after taking this medication. Additionally, certain foods like soybean flour (found in infant formula) may affect how this medication works in your body. Discuss this with your doctor.
Establishing a Routine
Take your medication at the same time every day. Continue taking your medication as directed by your doctor or healthcare provider, even if you're feeling well.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of your medication, consult your pharmacist. You may also want to check if there are drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses.
Lifestyle & Tips
- Take this medication exactly as prescribed by your doctor, usually once daily on an empty stomach, at least 30-60 minutes before breakfast or at bedtime (at least 3-4 hours after your last meal).
- Do not take this medication at the same time as calcium, iron, antacids, or cholesterol-lowering medications (like cholestyramine). Separate doses by at least 4 hours.
- Do not stop taking this medication without consulting your doctor, even if you feel better. Thyroid hormone replacement is usually a lifelong therapy.
- Inform your doctor about all other medications, supplements, and herbal products you are taking, as many can interact with thyroid hormones.
- Report any new or worsening symptoms to your doctor promptly.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial dose typically 15-30 mg (0.25-0.5 grain) orally once daily, adjusted in 15 mg increments every 2-3 weeks based on clinical response and laboratory parameters (TSH, free T4). Usual maintenance dose is 60-120 mg (1-2 grains) daily.
Dose Range:
15 - 300 mg
Condition-Specific Dosing:
hypothyroidism:
Initial dose 15-30 mg daily, titrated every 2-3 weeks. Maintenance 60-120 mg daily. Higher doses may be needed for some patients.
myxedema_coma:
Not indicated for acute myxedema coma; IV levothyroxine is preferred.
Pediatric Dosing
Neonatal:
Initial dose 4.8-6 mg/kg/day (0.08-0.1 grain/kg/day) orally, adjusted based on TSH and free T4. Due to critical importance for neurological development, prompt initiation and careful monitoring are essential.
Infant:
Initial dose 3-4.8 mg/kg/day (0.05-0.08 grain/kg/day) orally, adjusted based on TSH and free T4.
Child:
Initial dose 2.4-3.6 mg/kg/day (0.04-0.06 grain/kg/day) orally, adjusted based on TSH and free T4.
Adolescent:
Initial dose 1.2-2.4 mg/kg/day (0.02-0.04 grain/kg/day) orally, adjusted based on TSH and free T4, or adult dosing may be appropriate for older adolescents.
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment typically required.
Moderate:
No specific dose adjustment typically required.
Severe:
No specific dose adjustment typically required.
Dialysis:
No specific dose adjustment typically required. Thyroid hormones are not significantly dialyzable.
Hepatic Impairment:
Mild:
No specific dose adjustment typically required.
Moderate:
No specific dose adjustment typically required.
Severe:
No specific dose adjustment typically required.
Pharmacology
Mechanism of Action
Desiccated thyroid is a natural product derived from porcine thyroid glands, containing both levothyroxine (T4) and liothyronine (T3) in a physiological ratio. It acts as a replacement for endogenous thyroid hormones, which regulate metabolism, growth, and development by binding to nuclear thyroid hormone receptors and modulating gene expression.
Pharmacokinetics
Absorption:
Bioavailability:
Variable (approximately 48-80% for T4 component, higher for T3 component).
Tmax:
T4: 2-4 hours; T3: 1-2 hours.
FoodEffect:
Food, especially fiber, calcium, iron, and soy products, can decrease absorption. Should be taken on an empty stomach.
Distribution:
Vd:
T4: 10-12 L; T3: 0.4-0.6 L/kg.
ProteinBinding:
T4: >99% (primarily to thyroxine-binding globulin, transthyretin, and albumin); T3: ~99% (less avidly than T4).
CnssPenetration:
Limited, but active transport mechanisms exist for entry into the brain.
Elimination:
HalfLife:
T4: Approximately 6-7 days; T3: Approximately 1 day.
Clearance:
T4: 1.2 L/day; T3: 24 L/day.
ExcretionRoute:
Primarily renal (conjugated metabolites), some fecal excretion.
Unchanged:
Minimal unchanged excretion.
Pharmacodynamics
OnsetOfAction:
Gradual, clinical effects may take several days to weeks to become apparent due to the long half-life of T4 and the need for TSH suppression.
PeakEffect:
Clinical peak effect typically seen after 3-6 weeks of consistent dosing, once steady-state is achieved.
DurationOfAction:
Long, due to the long half-life of T4, allowing for once-daily dosing.
Safety & Warnings
Side Effects
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 or seek immediate 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 heartbeat or abnormal heartbeat
Shortness of breath
Sudden weight gain or swelling in the arms or legs
Headache
Feeling tired or weak
Shakiness
Trouble sleeping
Sensitivity to heat
Excessive sweating
Changes in appetite
Unintentional weight changes
Diarrhea
Stomach cramps
Vomiting
Irritability, nervousness, excitability, anxiety, or other mood changes
Fever
Muscle cramps
Muscle weakness
Flushing
Bone pain
Changes in menstrual periods
Other Possible Side Effects
Like all medications, this drug can cause side effects. However, many people experience no side effects or only mild ones. If you're bothered by any of the following side effects or if they persist, contact your doctor:
* 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.
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 or seek immediate 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 heartbeat or abnormal heartbeat
Shortness of breath
Sudden weight gain or swelling in the arms or legs
Headache
Feeling tired or weak
Shakiness
Trouble sleeping
Sensitivity to heat
Excessive sweating
Changes in appetite
Unintentional weight changes
Diarrhea
Stomach cramps
Vomiting
Irritability, nervousness, excitability, anxiety, or other mood changes
Fever
Muscle cramps
Muscle weakness
Flushing
Bone pain
Changes in menstrual periods
Other Possible Side Effects
Like all medications, this drug can cause side effects. However, many people experience no side effects or only mild ones. If you're bothered by any of the following side effects or if they persist, contact your doctor:
* 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.
Seek Immediate Medical Attention If You Experience:
- Symptoms of too much thyroid hormone (hyperthyroidism): Fast or irregular heartbeat, chest pain, shortness of breath, nervousness, irritability, insomnia, tremor, excessive sweating, heat intolerance, unexplained weight loss, diarrhea.
- Symptoms of too little thyroid hormone (hypothyroidism, if dose is too low): Persistent fatigue, weight gain, constipation, dry skin, hair loss, feeling cold, depression, slow heart rate.
Before Using This Medicine
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
This list is not exhaustive, and it is crucial to discuss all your health problems and medications with your doctor.
To ensure your safety, please inform 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.
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
This list is not exhaustive, and it is crucial to discuss all your health problems and medications with your doctor.
To ensure your safety, please inform 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.
Precautions & Cautions
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 drug 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), consult with your doctor, as this drug may occasionally affect blood sugar control. As a result, your diabetes medications may need to be adjusted. Follow your doctor's instructions for monitoring your blood sugar levels and undergo blood work and other laboratory tests as directed.
If you are taking biotin or a product containing biotin, discontinue its use at least 2 days prior to having your thyroid levels checked. This medication is derived from pork (pig) thyroid tissue, which carries a minimal risk of transmitting a viral disease. Although no cases have been reported, discuss any concerns with your doctor.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Pregnant women, those planning to become pregnant, or breastfeeding mothers should consult their doctor to discuss the potential benefits and risks of this medication to both themselves and their baby.
If you have diabetes (high blood sugar), consult with your doctor, as this drug may occasionally affect blood sugar control. As a result, your diabetes medications may need to be adjusted. Follow your doctor's instructions for monitoring your blood sugar levels and undergo blood work and other laboratory tests as directed.
If you are taking biotin or a product containing biotin, discontinue its use at least 2 days prior to having your thyroid levels checked. This medication is derived from pork (pig) thyroid tissue, which carries a minimal risk of transmitting a viral disease. Although no cases have been reported, discuss any concerns with your doctor.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Pregnant women, those planning to become pregnant, or breastfeeding mothers should consult their doctor to discuss the potential benefits and risks of this medication to both themselves and their baby.
Overdose Information
Overdose Symptoms:
- Signs and symptoms of hyperthyroidism (see above)
- Severe chest pain, palpitations, rapid pulse
- Confusion, disorientation
- Seizures
- Shock, coma
What to Do:
Seek immediate medical attention. Call 911 or your local emergency number. For non-emergencies, call Poison Control at 1-800-222-1222.
Drug Interactions
Contraindicated Interactions
- Acute myocardial infarction (unless associated with severe hypothyroidism)
- Uncorrected adrenal cortical insufficiency (Addison's disease)
- Untreated thyrotoxicosis
Major Interactions
- Anticoagulants (e.g., Warfarin): May increase anticoagulant effect by increasing catabolism of vitamin K-dependent clotting factors. Monitor INR closely.
- Antidiabetic agents (e.g., Insulin, Metformin, Sulfonylureas): May increase blood glucose levels, requiring increased doses of antidiabetic agents.
- Cholestyramine, Colestipol, Sevelamer: May bind thyroid hormones in the gut, reducing absorption. Administer thyroid hormone at least 4 hours before or after these agents.
- Iron supplements, Calcium supplements, Antacids (aluminum, magnesium, calcium carbonate), Sucralfate: May impair absorption of thyroid hormones. Administer thyroid hormone at least 4 hours before or after these agents.
- Proton Pump Inhibitors (PPIs) and H2-receptor antagonists: May reduce gastric acidity, potentially impairing absorption of thyroid hormones. Monitor TSH.
- Phenytoin, Carbamazepine, Rifampin, Phenobarbital: May increase metabolism of thyroid hormones, requiring higher doses of thyroid replacement.
- Amiodarone: Can cause hypo- or hyperthyroidism and alter thyroid hormone metabolism. Monitor thyroid function closely.
- Beta-blockers: May reduce the peripheral conversion of T4 to T3. Monitor thyroid function.
- Selective Serotonin Reuptake Inhibitors (SSRIs) and Tricyclic Antidepressants (TCAs): May increase the risk of cardiac arrhythmias when used concurrently with thyroid hormones, especially in patients with underlying cardiac disease.
Moderate Interactions
- Estrogens (oral), Androgens: May increase thyroid-binding globulin (TBG) levels, increasing bound thyroid hormone and potentially requiring higher doses of thyroid replacement.
- Corticosteroids: May inhibit TSH secretion and peripheral conversion of T4 to T3.
- Digoxin: Thyroid hormones may increase digoxin clearance, potentially requiring higher digoxin doses.
- Ketamine: Concurrent use may result in hypertension and tachycardia.
Minor Interactions
- Dietary fiber, Soy products: May decrease absorption of thyroid hormones. Advise consistent intake or separation of dosing.
Monitoring
Baseline Monitoring
Thyroid Stimulating Hormone (TSH)
Rationale: Primary indicator of thyroid function and adequacy of replacement therapy.
Timing: Prior to initiation of therapy.
Free Thyroxine (Free T4)
Rationale: Assesses circulating unbound T4 levels, which is the metabolically active form.
Timing: Prior to initiation of therapy.
Clinical symptoms of hypothyroidism
Rationale: To establish baseline symptom severity and track improvement.
Timing: Prior to initiation of therapy.
Cardiac status (ECG, history of heart disease)
Rationale: To assess risk of adverse cardiac events, especially in elderly or those with pre-existing heart conditions, as thyroid hormones can increase cardiac workload.
Timing: Prior to initiation of therapy.
Routine Monitoring
Thyroid Stimulating Hormone (TSH)
Frequency: Every 6-8 weeks after initiation or dose change, then every 6-12 months once stable.
Target: Typically 0.4-4.0 mIU/L (individualized based on patient age, comorbidities, and clinical goals).
Action Threshold: Adjust dose if TSH is outside target range or if symptoms persist/worsen.
Free Thyroxine (Free T4)
Frequency: Often monitored with TSH, especially during initial titration or if TSH is suppressed.
Target: Typically within the upper half of the reference range, but individualized.
Action Threshold: Adjust dose if Free T4 is consistently outside target range or if symptoms persist/worsen.
Clinical symptoms of hypo- or hyperthyroidism
Frequency: At every visit.
Target: Resolution of hypothyroid symptoms without development of hyperthyroid symptoms.
Action Threshold: Adjust dose if symptoms of hypo- or hyperthyroidism are present.
Bone mineral density (for long-term use, especially in postmenopausal women)
Frequency: Periodically, as clinically indicated (e.g., every 1-2 years for high-risk patients).
Target: Maintain normal bone density.
Action Threshold: Consider dose reduction if TSH is consistently suppressed below normal range, increasing risk of osteoporosis.
Symptom Monitoring
- Hypothyroidism: Fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss, depression, bradycardia, muscle aches, menstrual irregularities.
- Hyperthyroidism (overdose/over-replacement): Palpitations, tachycardia, nervousness, irritability, insomnia, weight loss, heat intolerance, sweating, tremor, diarrhea, menstrual irregularities, chest pain.
Special Patient Groups
Pregnancy
Thyroid hormone requirements often increase during pregnancy. It is crucial to maintain a euthyroid state throughout pregnancy for optimal fetal development and maternal health. Desiccated thyroid is Category A, meaning studies in pregnant women have not shown a risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Adequate thyroid hormone is critical for fetal neurological development. Untreated maternal hypothyroidism can lead to impaired cognitive development in the offspring.
Second Trimester:
Continued need for adequate thyroid hormone. Dose adjustments may be necessary as pregnancy progresses.
Third Trimester:
Dose adjustments may continue to be necessary. Monitor TSH every 4-6 weeks.
Lactation
Thyroid hormones are minimally excreted into breast milk. Desiccated thyroid is considered safe for use during breastfeeding and is compatible with lactation (L1).
Infant Risk:
Minimal to no risk to the breastfed infant at therapeutic maternal doses.
Pediatric Use
Thyroid hormone replacement is critical for normal growth and development in children with hypothyroidism. Dosing is weight-based and requires careful titration and monitoring of TSH and free T4 to prevent developmental delays, particularly neurological impairment in infants.
Geriatric Use
Elderly patients may be more sensitive to the effects of thyroid hormones, particularly cardiac effects. A lower starting dose and slower titration are recommended. Monitor for signs of cardiac dysfunction (e.g., angina, arrhythmias).
Clinical Information
Clinical Pearls
- Desiccated thyroid contains both T4 and T3. While some patients prefer it, levothyroxine (synthetic T4) is generally considered the standard of care due to its consistent potency and longer half-life.
- Dosing is highly individualized and based on clinical response and laboratory parameters (primarily TSH and free T4).
- Patients should be advised to take the medication consistently at the same time each day, preferably on an empty stomach, to optimize absorption.
- Emphasize the importance of separating administration from interacting medications and supplements (e.g., calcium, iron, antacids) by at least 4 hours.
- Symptoms of over-replacement (hyperthyroidism) or under-replacement (hypothyroidism) should be promptly reported to the healthcare provider.
- Regular monitoring of thyroid function tests is essential, especially after dose changes or initiation of new medications that may interact.
Alternative Therapies
- Levothyroxine (synthetic T4): Most commonly prescribed thyroid hormone replacement, available as various brand names (e.g., Synthroid, Levoxyl, Unithroid) and generic.
- Liothyronine (synthetic T3): Used less commonly alone due to shorter half-life and higher peak T3 levels, but sometimes used in combination with levothyroxine for specific cases.
- Liotrix (combination of T4 and T3 in a fixed 4:1 ratio): Less commonly used than levothyroxine or desiccated thyroid.
Cost & Coverage
Average Cost:
$15 - $50 per 30 tablets (0.5gr/30mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (preferred generic) on most insurance formularies.
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, 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 check with your pharmacist for more information. If you have any questions or concerns about this medication, consult 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 details about the overdose, including the medication taken, the amount, and the time it occurred.