Eltroxin (Levothyroxine Sodium)
Also sold as: Eltroxin, Thyronorm, Thyrox, Lethyrox
Pregnancy
Cat A
Lactation
Safe
Schedule
H
Forms
Tablet 12.5/25/50/75/88/100/112/125/150/200mcg
Indications
- Primary hypothyroidism
- Subclinical hypothyroidism (TSH >10 or symptoms)
- TSH suppression in thyroid cancer
- Goitre
Adult Dosing
Hypothyroidism (full replacement)
1.6 mcg/kg PO once daily on empty stomach
30-60 min before breakfast
Elderly / cardiac
Start 25-50 mcg, titrate by 12.5-25 mcg every 4-6 weeks
Pregnancy
Increase pre-pregnancy dose by 25-30% as soon as pregnancy confirmed
Pediatric Dosing
Doses decrease with age: infants 8-10 mcg/kg, children 4-6 mcg/kg, adolescents 2-4 mcg/kg
Renal Dose Adjustment
| CrCl / eGFR | Dose Adjustment |
|---|---|
| No adjustment needed | No CrCl-based dose adjustment required |
Hepatic Adjustment
No adjustment
Pregnancy & Lactation
Pregnancy: Category A
Required throughout pregnancy. Increase dose by 25-30% in 1st trimester. Target TSH <2.5 mIU/L
Lactation: Safe
Top Drug Interactions
| Interacting Drug | Effect | Severity |
|---|---|---|
| Iron, calcium, antacids, sucralfate, soy, coffee | Reduced absorption — separate by 4 hours | Major |
| Estrogens, OCPs | Increased TBG → may need higher dose | Moderate |
| Warfarin | Increased anticoagulant effect | Moderate |
| Phenytoin, rifampicin, carbamazepine | Increased levothyroxine clearance | Moderate |
| Cholestyramine | Reduced absorption — separate by 4 hours | Major |
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Side Effects
Common
- Generally well-tolerated when correctly dosed
Serious / Discontinue If
- Iatrogenic thyrotoxicosis (overdose): palpitations, weight loss, anxiety, AF, osteoporosis (long-term)
- Acute MI/angina exacerbation in elderly with CAD
Contraindications
- Untreated adrenal insufficiency
- Untreated thyrotoxicosis
- Acute MI
- Hypersensitivity
Available Indian Brands
| Brand | Manufacturer | Price (approx) |
|---|---|---|
| Eltroxin 100mcg | GSK | 120 tab ₹165 |
| Thyronorm 100mcg | Abbott | 120 tab ₹155 |
| Thyrox 100mcg | Macleods | 120 tab ₹125 |
| Lethyrox 100mcg | Sun Pharma | 100 tab ₹120 |
Monitoring Required
- TSH every 6-8 weeks until stable, then every 6-12 months
- TSH within 4 weeks if dose change
- Bone density in long-term suppressive therapy
Patient Counseling Points
- Take FIRST thing in morning, empty stomach, 30-60 min before breakfast
- Avoid taking with iron, calcium, soy, coffee
- Take same brand consistently — bioequivalence varies
- Lifelong therapy in most cases
- Increase dose if pregnant
Stop Googling drug references mid-consultation
EasyClinic auto-flags Eltroxin interactions, renal cutoffs, and pregnancy warnings the moment you write the prescription. Built-in safety net for every Indian doctor.
References
- BNF
- Lexicomp Drug Information
- Indian National Formulary
- Specialty society guidelines (RSSDI/CSI/IAP)