Thyroid Np 1.5gr (90mg) 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 combination)
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 of the main thyroid hormones, T4 and T3, which your body normally makes. It's used to treat an underactive thyroid gland (hypothyroidism) to help your body's metabolism work properly. It's important to take it exactly as prescribed, usually on an empty stomach, to ensure consistent absorption.
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, some foods, such as 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 disposal, 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, some foods, such as 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 disposal, 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 the medication consistently at the same time each day, preferably in the morning on an empty stomach, at least 30-60 minutes before food or other medications.
- Avoid taking calcium, iron, antacids, or fiber supplements within 4 hours of your thyroid medication, as they can interfere with absorption.
- Do not stop taking this medication without consulting your doctor, even if you feel better. Thyroid hormone replacement is usually a lifelong therapy.
- Report any new or worsening symptoms to your doctor, especially signs of overactive thyroid (e.g., rapid heart rate, nervousness, sweating, unexplained weight loss) or underactive thyroid (e.g., fatigue, weight gain, constipation, cold intolerance).
- Inform all healthcare providers, including dentists and pharmacists, that you are taking thyroid hormone.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 15-30 mg (1/4 to 1/2 grain) orally once daily. Titrate by 15 mg increments every 2-3 weeks based on clinical response and laboratory parameters (TSH, Free T4). Maintenance: 60-120 mg (1-2 grains) orally once daily. The 90mg (1.5gr) is a common maintenance dose.
Dose Range:
15 - 180 mg
Condition-Specific Dosing:
elderly_cardiac_disease:
Start with 7.5-15 mg (1/8 to 1/4 grain) orally once daily, titrate slowly.
Pediatric Dosing
Neonatal:
Initial: 10-15 mcg/kg/day (levothyroxine equivalent) or 7.5-15 mg (1/8 to 1/4 grain) orally once daily, adjusted based on TSH and T4 levels.
Infant:
Initial: 7.5-15 mg (1/8 to 1/4 grain) orally once daily, adjusted based on TSH and T4 levels.
Child:
Initial: 15-30 mg (1/4 to 1/2 grain) orally once daily, adjusted based on TSH and T4 levels.
Adolescent:
Initial: 30-60 mg (1/2 to 1 grain) orally once daily, adjusted based on TSH and T4 levels.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment generally needed.
Moderate:
No specific adjustment generally needed.
Severe:
No specific adjustment generally needed, but monitor for symptoms of over- or under-treatment.
Dialysis:
No specific adjustment generally needed, but monitor closely.
Hepatic Impairment:
Mild:
No specific adjustment generally needed.
Moderate:
No specific adjustment generally needed.
Severe:
No specific adjustment generally needed, but monitor for symptoms of over- or under-treatment.
Pharmacology
Mechanism of Action
Desiccated thyroid contains both levothyroxine (T4) and liothyronine (T3), the two primary thyroid hormones. These hormones exert their metabolic effects through control of DNA transcription and protein synthesis. They bind to thyroid hormone receptors in the cell nucleus, regulating gene expression and influencing various metabolic processes, including protein, carbohydrate, and lipid metabolism, as well as growth and development.
Pharmacokinetics
Absorption:
Bioavailability:
Variable (T4 ~48-80%, T3 ~95%). Desiccated thyroid absorption can be inconsistent due to natural variations in the product and excipients.
Tmax:
T4: 2-4 hours; T3: 1-2 hours (for the components within desiccated thyroid).
FoodEffect:
Food, especially fiber, calcium, iron, and soy products, can decrease absorption. Should be taken on an empty stomach, at least 30-60 minutes before breakfast.
Distribution:
Vd:
T4: 10-13 L; T3: 0.46 L/kg.
ProteinBinding:
T4: >99% (primarily to thyroxine-binding globulin (TBG), transthyretin, and albumin); T3: ~99% (less avidly than T4).
CnssPenetration:
Limited, but active transport systems facilitate entry into the brain.
Elimination:
HalfLife:
T4: 6-7 days; T3: 1-2 days (components within desiccated thyroid).
Clearance:
T4: 1.1 L/day; T3: 2.3 L/day.
ExcretionRoute:
Primarily renal (conjugated metabolites), some biliary/fecal.
Unchanged:
Minimal unchanged excretion.
Pharmacodynamics
OnsetOfAction:
Gradual, typically days to weeks for full therapeutic effect due to T4 component.
PeakEffect:
Weeks for TSH stabilization.
DurationOfAction:
Long, due to the long half-life of T4.
Safety & Warnings
BLACK BOX WARNING
Thyroid hormones, including Thyroid, Desiccated, should not be used for the treatment of obesity or for weight loss. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects. A slightly different wording may be found on specific product labels, but the core message is consistent.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
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 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 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. 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 guidance:
* Hair loss (often 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.
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 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 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. 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 guidance:
* Hair loss (often 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:
- Signs of too much thyroid hormone (hyperthyroidism): rapid or irregular heartbeat, chest pain, shortness of breath, nervousness, irritability, insomnia, tremor, excessive sweating, heat intolerance, unexplained weight loss, diarrhea.
- Signs of too little thyroid hormone (hypothyroidism) despite treatment: persistent fatigue, weight gain, constipation, cold intolerance, dry skin, hair loss, depression, memory problems.
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, 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, including any medical conditions or allergies
Before starting, stopping, or changing the dose of any medication, including this one, consult with your doctor to confirm it is safe 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, 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, including any medical conditions or allergies
Before starting, stopping, or changing the dose of any medication, including this one, consult with your doctor to confirm it is safe 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. You may need to wait 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. Your doctor may need to adjust your diabetes medications. 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 before 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. Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. Your doctor will help you weigh the benefits and risks of this medication for both you and your baby.
If you have diabetes (high blood sugar), consult with your doctor, as this drug may occasionally affect blood sugar control. Your doctor may need to adjust your diabetes medications. 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 before 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. Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. Your doctor will help you weigh the benefits and risks of this medication for both you and your baby.
Overdose Information
Overdose Symptoms:
- Signs and symptoms of hyperthyroidism (thyrotoxicosis): headache, irritability, nervousness, sweating, tachycardia, arrhythmias, palpitations, chest pain, diarrhea, tremor, insomnia, heat intolerance, fever, weight loss, menstrual irregularities, convulsions (rarely), shock (rarely).
What to Do:
Seek immediate medical attention or call a poison control center (e.g., 1-800-222-1222). Treatment is symptomatic and supportive, including reducing absorption (e.g., activated charcoal if recent ingestion), beta-blockers for cardiac symptoms, and corticosteroids for severe cases.
Drug Interactions
Major Interactions
Moderate Interactions
- Antacids (aluminum, magnesium, calcium-containing): Decreased thyroid hormone absorption.
- Iron supplements: Decreased thyroid hormone absorption.
- Calcium supplements: Decreased thyroid hormone absorption.
- Bile acid sequestrants (cholestyramine, colestipol): Decreased thyroid hormone absorption.
- Sucralfate: Decreased thyroid hormone absorption.
- Proton pump inhibitors (PPIs) / H2 blockers: May alter gastric pH, potentially affecting absorption.
- Enzyme-inducing anticonvulsants (phenytoin, carbamazepine, phenobarbital): Increased thyroid hormone metabolism.
- Rifampin: Increased thyroid hormone metabolism.
- Estrogens/Oral contraceptives: May increase TBG, requiring higher thyroid hormone dose.
- Androgens/Anabolic steroids: May decrease TBG, potentially requiring lower thyroid hormone dose.
- Beta-blockers: May decrease conversion of T4 to T3.
- Amiodarone: Can cause hypo- or hyperthyroidism, and alter T4 to T3 conversion.
Minor Interactions
- Dietary fiber: May decrease absorption if taken concurrently.
Monitoring
Baseline Monitoring
Thyroid Stimulating Hormone (TSH)
Rationale: Primary indicator of thyroid function and adequacy of replacement therapy.
Timing: Before initiating therapy.
Free Thyroxine (Free T4)
Rationale: Assesses circulating unbound T4 levels.
Timing: Before initiating therapy.
Clinical symptoms of hypothyroidism
Rationale: To establish baseline and track improvement.
Timing: Before initiating therapy.
Cardiac status (ECG, heart rate, blood pressure)
Rationale: To assess for pre-existing cardiac conditions, especially in elderly or those with cardiovascular risk factors, as thyroid hormones can increase cardiac workload.
Timing: Before initiating therapy, particularly in older adults or those with heart disease.
Routine Monitoring
Thyroid Stimulating Hormone (TSH)
Frequency: Every 6-8 weeks after initiation or dose change, then every 6-12 months once stable.
Target: 0.4-4.0 mIU/L (individualized based on patient age, comorbidities, and clinical response).
Action Threshold: TSH outside target range; adjust dose.
Free Thyroxine (Free T4)
Frequency: Every 6-8 weeks after initiation or dose change, then every 6-12 months once stable (often monitored with TSH).
Target: 0.8-1.8 ng/dL (or within upper half of reference range for some patients).
Action Threshold: Free T4 outside target range, especially if TSH is also abnormal; adjust dose.
Clinical symptoms of hypo- or hyperthyroidism
Frequency: At every visit.
Target: Resolution of hypothyroid symptoms, absence of hyperthyroid symptoms.
Action Threshold: Persistent hypothyroid symptoms or emergence of hyperthyroid symptoms; consider dose adjustment or further investigation.
Heart rate and blood pressure
Frequency: At every visit, especially during dose titration.
Target: Normal range for age and patient.
Action Threshold: Tachycardia, palpitations, or hypertension; may indicate over-replacement.
Symptom Monitoring
- Fatigue
- Weight gain
- Constipation
- Cold intolerance
- Dry skin
- Hair loss
- Bradycardia
- Depression
- Memory impairment
- Anxiety
- Nervousness
- Palpitations
- Tachycardia
- Weight loss (unexplained)
- Heat intolerance
- Diarrhea
- Tremor
- Insomnia
- Sweating
Special Patient Groups
Pregnancy
Thyroid hormone replacement is essential during pregnancy for both maternal and fetal health. Hypothyroidism during pregnancy can lead to adverse outcomes for both mother and child. Desiccated thyroid is Category A, meaning adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester (and there is no evidence of risk in later trimesters). Dose requirements often increase during pregnancy.
Trimester-Specific Risks:
First Trimester:
Untreated maternal hypothyroidism in the first trimester is associated with increased risk of miscarriage, preterm birth, and impaired neurocognitive development in the offspring. Adequate thyroid hormone levels are crucial for fetal brain development.
Second Trimester:
Continued need for adequate thyroid hormone levels. Dose adjustments may be necessary.
Third Trimester:
Continued need for adequate thyroid hormone levels. Dose adjustments may be necessary. Monitor TSH and Free T4 regularly.
Lactation
Thyroid hormones are excreted in breast milk in minimal amounts and are generally considered compatible with breastfeeding. No adverse effects on the infant have been reported with maternal therapeutic doses. It is important for the mother to maintain euthyroid status for her own health and to support lactation.
Infant Risk:
L1 (Safest) - No known adverse effects on the breastfed infant.
Pediatric Use
Thyroid hormone replacement is critical for normal growth and development in children with hypothyroidism. Dosing is weight-based and adjusted frequently based on TSH and Free T4 levels. Inadequate treatment can lead to irreversible intellectual disability and growth retardation (cretinism in severe congenital cases).
Geriatric Use
Elderly patients, particularly those with underlying cardiovascular disease, may be more sensitive to the effects of thyroid hormones. Lower starting doses and slower titration are recommended to avoid precipitating cardiac events (e.g., angina, arrhythmias). Monitor closely for signs of hyperthyroidism.
Clinical Information
Clinical Pearls
- Desiccated thyroid contains both T4 and T3. While some patients prefer it, the T3 component can lead to more fluctuating T3 levels and potentially more symptoms of hyperthyroidism if not carefully dosed, compared to levothyroxine (T4 only).
- The potency of desiccated thyroid can vary slightly between batches and manufacturers due to its natural origin, which may necessitate more frequent monitoring and dose adjustments compared to synthetic levothyroxine.
- Always take thyroid medication on an empty stomach, at least 30-60 minutes before food or other medications, to optimize absorption.
- Patients should be educated on the signs of both hypo- and hyperthyroidism, as dose adjustments are often guided by both laboratory values and clinical symptoms.
- TSH is the primary lab test for monitoring, but Free T4 should also be checked, especially when using desiccated thyroid, as TSH alone might not fully reflect the T3 component's effect.
- Avoid using thyroid hormones for weight loss in euthyroid individuals due to the risk of serious cardiac and other adverse effects.
Alternative Therapies
- Levothyroxine (synthetic T4, e.g., Synthroid, Levoxyl, Tirosint): Most commonly prescribed thyroid hormone replacement, considered standard of care.
- Liothyronine (synthetic T3, e.g., Cytomel): Used in specific cases, often in combination with levothyroxine, or for short-term T3 suppression.
- Combination therapy (synthetic T4/T3, e.g., Thyrolar, or compounded T4/T3): Used for patients who do not achieve optimal symptom control on levothyroxine alone, though evidence for superiority is mixed.
Cost & Coverage
Average Cost:
$15 - $50 per 30 tablets (90mg strength)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (preferred generic/brand)
General Drug Facts
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 medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.