MedicinePOMEssential

Levothyroxine Sodium

Levothyroxine is a thyroid hormone replacement for an underactive thyroid (hypothyroidism).

Clinical information

Common uses

underactive thyroid (hypothyroidism)

Common side effects

difficulty sleeping
headaches
feeling anxious
sweating
hair loss

Cautions

take on an empty stomach, 30-60 minutes before food or caffeine
regular blood tests needed to check the dose
may not suit heart, adrenal or overactive thyroid conditions
most side effects mean the dose is too high

Interactions

antacids, calcium and iron supplements (affect absorption)
omeprazole and other acid-reducing medicines
carbamazepine (epilepsy medicine)
sertraline (antidepressant)
St John's wort
biotin (interferes with thyroid blood tests)

Pregnancy: can be taken — extra blood tests to adjust the dose

Reference information, not medical advice — always follow your doctor or pharmacist. Source: NHS Medicines A–Z, nhs.uk/medicines/levothyroxine (accessed 2026-08-16)

Approved brands & formulations10

Brand name	Dosage form	Strength	Importer	Category
Levothyroxine	Tablet	75mcg	—	POM
Levothyroxine Sodium	Tablet	50 mcg	—	POM
Levothyroxine Sodium	Tablet	100 mcg	—	POM
Levothyroxine Sodium	Tablet	25 mcg	—	POM
T4 Montpellier	Tablet	100 mcg	authorized medicine importers	POM
Thyrox 100	Tablet ( Uncoated Tablet )	100mcg (USP)	—	POM
Thyrox 25	Tablet ( Uncoated Tablet )	25mcg	—	POM
Thyrox 50	Tablet ( Uncoated Tablet )	—	—	POM
Thyrox 75	Tablet ( Uncoated Tablet )	75mcg	—	POM
Thyroxin 100	Tablet ( Uncoated Tablet )	100 mcg (BP)	ADK Pharmaceutical Company Pvt. Ltd	POM