Product Description

Indications:

Thyrin is used as replacement therapy in hypothyroidism of any cause. It is also used to suppress TSH in goitre, thyroid nodules and after thyroid cancer treatment, to counteract goitrogenic effects of certain drugs (e.g., lithium) and as a diagnostic aid in thyroid suppression tests.

Pharmacology:

Levothyroxine (T4) is a synthetic thyroid hormone identical to natural thyroxine. It is converted into the active hormone T3 in peripheral tissues. It regulates metabolism and has a long half-life (about 6–7 days), allowing once-daily dosing and stable hormone levels.

Dosage and Administration:

Dose is individualized based on patient condition and lab results.

Adults: Initial dose 25–50 mcg daily, increased gradually every 6–8 weeks.

Severe hypothyroidism: Start with 12.5–25 mcg daily and titrate slowly.

Children: Dose varies by age and weight (generally 2–15 mcg/kg/day).

Elderly or cardiac patients: Lower starting doses are recommended. Adjust dose based on TSH and clinical response.

Drug Interactions:

May interact with antidepressants, antidiabetic drugs, insulin, sertraline and digoxin. Dose adjustments may be required and monitoring is necessary.

Contraindications:

Contraindicated in untreated thyrotoxicosis, acute myocardial infarction and uncorrected adrenal insufficiency.

Side Effects:

Side effects are usually due to overdose and resemble hyperthyroidism, including weight loss, sweating, nervousness, palpitations, tremors, insomnia and diarrhea.

Pregnancy and Lactation:

Safe in pregnancy (Category A), though dose may need adjustment. Small amounts pass into breast milk, but generally safe during breastfeeding.

Precautions and Warnings:

Use cautiously in patients with heart disease or adrenal insufficiency. Avoid rapid dose increases. Regular monitoring of thyroid function (TSH, T4) is essential.

Overdose Effects:

Overdose may cause symptoms of hyperthyroidism such as tachycardia, agitation, fever and arrhythmia. Treatment is supportive and dose reduction or discontinuation may be required.

Therapeutic Class:

Thyroid Hormone Replacement

Storage Conditions:

Store below 30°C in a dry place, protect from light, and keep out of reach of children.

⚠️ Use under the supervision of a registered healthcare professional.