💊 Levothyroxine Tablet 12.5 mcg to 150 mcg – As Licensed
📄 Description:
Levothyroxine is a synthetic form of thyroxine (T4), the primary hormone secreted by the thyroid gland. It is used to replace or supplement endogenous thyroid hormone in hypothyroid patients.
It is available in a range of strengths (12.5 mcg to 150 mcg) to allow precise dosing and titration based on patient needs.
🧾 Prescription / Use:
Indications:
- Primary hypothyroidism (due to Hashimoto’s thyroiditis, thyroidectomy, etc.)
- Secondary/tertiary hypothyroidism (pituitary or hypothalamic dysfunction)
- Goiter suppression
- Adjunct to treatment of thyroid cancer
- Congenital hypothyroidism in neonates
Dosage:
- Individualized based on age, body weight, cardiovascular status, and lab values
- Typical starting dose for adults: 25–50 mcg/day
- Elderly or cardiac patients: 12.5–25 mcg/day
- Maintenance dose: 75–150 mcg/day
- Neonates/infants: Weight-based dosing
Route: Oral
Frequency: Once daily, preferably in the morning on an empty stomach
🔬 Nature:
- Class: Thyroid hormone replacement
- Mechanism: Converts to triiodothyronine (T3) in peripheral tissues, influencing metabolism, growth, and development
- Form: Tablet
- Strengths available: 12.5 mcg, 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg (some variations by country)
🌟 Advantages:
- Replaces deficient thyroid hormone accurately
- Available in multiple strengths to ensure flexible dosing
- Improves symptoms like fatigue, weight gain, depression, and cold intolerance
- Long half-life (~7 days) allows once-daily dosing
- Widely studied and well tolerated
📦 Common Packaging:
- Blister packs or strips, typically with 10, 15, or 30 tablets
- Clearly marked dosage on each tablet and packaging
- Color-coded by strength to reduce confusion
🧊 Storage:
- Store below 25°C
- Protect from light and moisture
- Keep in original packaging
- Keep out of reach of children
⚠️ Precautions:
Contraindications:
- Untreated thyrotoxicosis
- Uncorrected adrenal insufficiency
- Known hypersensitivity
Use With Caution In:
- Elderly
- Cardiac patients (especially ischemic heart disease)
- Diabetics (can alter glycemic control)
- Patients with osteoporosis
Monitoring:
- Regular TSH and free T4 levels
- Reassess dose if patient becomes pregnant, gains/loses weight, or takes interacting medications
Drug Interactions:
- Reduced absorption with calcium, iron, antacids, cholestyramine
- Enhanced metabolism with rifampicin, carbamazepine, phenytoin
- Increased sensitivity to warfarin
👩⚕️ Patient Advice:
- Take daily on an empty stomach (30–60 min before breakfast)
- Avoid dairy, iron, or calcium supplements for at least 4 hours
- Do not skip or double doses—take missed dose as soon as remembered (if within 12 hrs)
- Inform doctor if pregnant or breastfeeding
- Improvement may take 2–4 weeks
- Regular blood tests are essential to adjust the dose