Medicines & Supplements A to Z > Levothyroxine

Levothyroxine

Last updated on 14/07/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions   |   Tips   |   Where To Buy  

GENERIC NAME: Levothyroxine

ALTERNATIVE NAME: Thyroxine, T4, L-thyroxine

CHINESE NAME: 左旋甲狀腺素

BRAND NAME(S) IN HONG KONG: Eltroxin, Oroxine

DRUG CLASS: Endocrine drugs

SUB CLASS: Hormones

USED FOR: Hypothyroidism, Treatment of thyroid cancer

AVAILABLE DOSAGE FORMS:
– 50mcg, 100mcg, 200mcg (tablets)

What is Levothyroxine for?

Levothyroxine, or called Thyroxine, is a synthetic thyroid hormone. It mimics the function of natural thyroid hormones that can treat hypothyroidism and thyroid cancer in patients with deficient thyroid function.

How to use it?

Levothyroxine is taken orally as tablets. 

For hypothyroidism:
Adult ≤50 years of age:
Initial: 50-100 mcg daily, and can be increased by 50 mcg at monthly intervals
Usual maintenance: 100-150 mcg daily

Elderly >50 years of age without heart disease, OR adult patients with heart disease:
Initial: 25-50 mcg, and can be increased by 25-50 mcg at monthly intervals
Usual maintenance: 50-150 mcg daily

Elderly >50 years of age, with heart disease:
Initial: 25 mcg, and can be increased by 25 mcg at monthly intervals
Usual maintenance: 50-150 mcg daily

For the treatment of thyroid cancer:
Dosage should be highly individualized by professionals.

What are the side effects of Levothyroxine?

Common side effects of Levothyroxine include headache, tremor, palpitation, fatigue, and fever.

Who should not take Levothyroxine?

– People who are allergic to Levothyroxine or any component of the formulation
– Patients with adrenal insufficiency

Pharmacist Tips:

– It may take several weeks to notice any improvement of symptoms.
– Do not stop taking the medication suddenly.
– Partial hair loss may happen during the first few months of therapy, but this is temporary.
– Do not take iron products, antacids, or calcium carbonate, within 4 hours before or 4 hours after taking this drug.

Common dosing schedule:
Levothyroxine should be taken on an empty stomach, at least 30-60 minutes before food.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Levothyroxine may interact with:
– Warfarin
– Digoxin
– Amiodarone
– Antiepileptics, e.g. Carbamazepine, Phenytoin
– Antidiabetic drugs, e.g. Insulin, Metformin
– Nonsteroidal anti-inflammatory drugs, e.g. Aspirin, Ibuprofen
– Contraceptives, e.g. Ethinylestradiol

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Levothyroxine in Hong Kong?

In Hong Kong, Levothyroxine is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Levothyroxine in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.