Thyrox 100 mcg Tablet

Thyrox 100 mcg tablet is manufactured by Renata PLC and contains Levothyroxine Sodium, a man-made version of thyroxine (T4), the main hormone produced by the thyroid gland. It is the standard treatment for hypothyroidism — an underactive thyroid — which is common in Bangladesh, especially among women.

Thyroxine controls the speed of almost every process in the body: energy use, heart rate, body temperature, digestion and growth. When the thyroid cannot make enough, people feel tired, gain weight, feel cold and develop dry skin and constipation. Thyrox simply replaces the missing hormone; the body converts it into the active form (T3) as needed, so with the correct daily dose the body works normally again.

Thyrox is prescribed for:

• Hypothyroidism from any cause — including Hashimoto's thyroiditis, after thyroid surgery, or after radioactive iodine treatment
• Congenital hypothyroidism in newborns and children, where early treatment protects brain development
• Hypothyroidism during pregnancy, where adequate hormone is essential for the baby
• Certain goitres, and TSH suppression after some thyroid cancers, under specialist care

It is not a tonic, a weight-loss medicine or a treatment for simple tiredness — it should be taken only when blood tests (TSH, with FT4 when needed) confirm the diagnosis and a doctor prescribes it.

The dose of Thyrox is individual — your doctor sets it according to your weight, age, heart condition and TSH level, then fine-tunes it with blood tests about every 6–8 weeks until stable. Never adjust the dose yourself.

• Take it once daily on an empty stomach, 30–60 minutes before breakfast, with plain water, at the same time every day.
• Keep tea, coffee, milk and food away from that window — they reduce absorption.
• Keep a gap of at least 4 hours from calcium, iron and antacid preparations.
• If you miss a dose, take it when you remember the same day; otherwise continue the next day — do not double up.

Treatment is usually lifelong, with periodic TSH checks.

At the correct dose, Thyrox simply restores normal hormone levels and causes few side effects; some people notice temporary hair shedding in the first months. Most problems come from a dose that is too high, which mimics an overactive thyroid:

• Palpitations, fast or irregular heartbeat, chest discomfort
• Tremor, anxiety, irritability, difficulty sleeping
• Sweating, heat intolerance, weight loss, diarrhoea
• In women, menstrual irregularities

Long-term over-replacement can thin the bones (osteoporosis) and trigger an irregular heart rhythm (atrial fibrillation), especially in older people. If such symptoms appear, do not stop the medicine abruptly — contact your doctor, who will recheck your TSH and adjust the dose.

To get the full benefit of Thyrox safely:

• Take it the same way every day — same time, same routine — because absorption habits change blood levels. Where possible, stay on the same brand; if the brand changes, a TSH recheck may be sensible.
• Tell your doctor if you have heart disease, angina, high blood pressure, diabetes or adrenal problems — treatment usually starts low and rises slowly, and adrenal insufficiency must be treated first.
• In diabetes, thyroid correction may change your sugar control, so monitor as advised.
• Tell your doctor if you are pregnant or planning pregnancy — the dose often needs increasing early in pregnancy.
• Stop biotin-containing supplements a few days before thyroid blood tests, as they can distort results — ask your doctor first.

Many common products interfere with Thyrox, mostly by blocking its absorption or changing its breakdown:

• Calcium and iron tablets, antacids, sucralfate — keep at least a 4-hour gap.
• Omeprazole-type acid reducers can lower absorption; tell your doctor if you use them regularly.
• Coffee, soy products and very high-fibre meals close to the dose reduce absorption — keep your routine consistent.
• Warfarin — the blood-thinning effect may increase; INR needs closer monitoring.
• Diabetes medicines may need adjusting as thyroid levels normalise.
• Oestrogens (including some contraceptives), rifampicin, carbamazepine and phenytoin can change levothyroxine requirements.

Always show your full medicine list to your doctor and pharmacist.

Do not take Thyrox if:

• You are allergic to Levothyroxine Sodium or any other ingredient
• You have an overactive thyroid (untreated thyrotoxicosis)
• You have untreated adrenal insufficiency — this must be corrected first, otherwise a dangerous adrenal crisis can occur
• You have had a very recent heart attack or unstable angina, unless your doctor specifically advises treatment

Thyrox must never be used for weight loss in people with a normal thyroid — high doses can cause serious, even life-threatening, heart effects. If you are unsure whether the medicine is right for you, confirm with your doctor before starting.

Thyrox is one of the few medicines that is both safe and essential during pregnancy when prescribed for hypothyroidism. The baby depends on the mother's thyroid hormone, especially in the first trimester, for brain development — so the medicine must not be stopped. In fact, the dose usually needs to be increased by around 25–30% in early pregnancy; inform your doctor as soon as pregnancy is confirmed and attend the more frequent TSH checks.

Levothyroxine at correct replacement doses is also considered safe during breastfeeding — only tiny amounts pass into milk. Continue your tablets and routine monitoring while nursing.

Levothyroxine is a sensitive medicine — heat, humidity and light can weaken it, which then shows up as poorly controlled thyroid tests. Store Thyrox below 25–30°C in a cool, dry place away from direct sunlight, keeping the tablet in its original blister or tightly closed container until use.

• Do not store it in the bathroom, kitchen or a hot car.
• Keep all medicines out of the reach and sight of children.
• Do not use after the expiry date, and ask your pharmacist about safe disposal of unused tablets.