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Indications & Uses
Thyronor is indicated for:
Pharmacology
This preparation contains synthetic Levothyroxine (also called Thyroxine or T4), which is identical to the natural hormone T4 produced in the Thyroid gland. About 30% of T4 is converted to the much more active Triiodothyronine (T3) in peripheral tissues. TBG (Thyroxine Binding Globulin) is the major carrier of T4. This binding protects T4 from metabolism and excretion, resulting in its long half-life in the circulation. Only about 0.03% of total T4 in plasma is unbound. The half-life of elimination of T4 is 6 to 7 days. In hyperthyroidism, the half-life is shortened to 3 or 4 days, whereas in hypothyroidism it may be 9 to 10 days. In conditions associated with reduced protein in plasma, such as nephrosis or hepatic cirrhosis, or when binding to protein is inhibited by certain drugs, the half-life of T4 may be shortened. The liver is the major site of degradation of Thyroid hormones. T4 is conjugated with Glucuronic and Sulphate conjugates through the Phenolic hydroxyl group and excreted in the urine. There is an enterohepatic circulation of the Thyroid hormones, since they are liberated by hydrolysis in the intestine and reabsorbed. Because of the long half-life of T4, a steady blood level of the biologically more active T3 can be obtained from a single daily dose of Levothyroxine. Therefore, variations in the therapeutic effect are unlikely once the correct dosage has been established.
Dosage Reference
Reference Information Only
Dosages shown are general references from official sources. Always consult your doctor or pharmacist for personalized dosing.
Adults:
Adult dose: The initial starting dose is usually 25 to 50 mcg per day, with gradual increases at intervals of 6 to 8 weeks as needed. The Levothyroxine Sodium dose is generally adjusted in steps of 12.5 to 25 mcg until the patient with primary hypothyroidism is clinically euthyroid and the serum TSH level has returned to normal. In patients with severe hypothyroidism, the initial dose is 12.5 to 25 mcg per day, with increases of 25 mcg per day every 2 to 4 weeks, along with clinical and laboratory assessment, until the TSH level is normal. In patients with secondary (pituitary) or tertiary (hypothalamic) hypothyroidism, the Levothyroxine Sodium dose should be adjusted until the patient is clinically euthyroid and the serum free T4 level is restored to the upper half of the normal range. For patients older than 50 years, or patients under 50 years of age with underlying heart disease, the dose is 1.7 mcg per kg per day.
Pediatric dosage for newborns: the recommended starting dose is 10 to 15 mcg per kg per day. A lower starting dose should be considered in infants at risk of heart failure, and the dose should be increased every 4 to 6 weeks as needed based on the clinical and laboratory response to treatment. In infants with very low serum T4 concentration (below 5 mcg per dL) or an undetectable level, the recommended initial starting dose is 50 mcg per day of Levothyroxine Sodium.
Pediatric dosage for infants and children: in children with chronic or severe hypothyroidism, the initial dose is 25 mcg per day, with increases of 25 mcg every 2 to 4 weeks until the desired effect is achieved. Hyperactivity in an older child can be reduced if the starting dose is one fourth of the recommended full replacement dose, with the dose then increased weekly by an amount equal to one fourth of the full recommended replacement dose, until the full recommended replacement dose is reached. From 0 to 3 months, the dose is 10 to 15 mcg per kg per day. From 3 to 6 months, it is 8 to 10 mcg per kg per day. From 6 to 12 months, it is 6 to 8 mcg per kg per day. From 1 to 5 years, it is 5 to 6 mcg per kg per day. From 6 to 12 years, it is 4 to 5 mcg per kg per day. Over 12 years but with growth and puberty not yet complete, it is 2 to 3 mcg per kg per day. Once growth and puberty are complete, it is 1.7 mcg per kg per day. The dose should be adjusted based on the patient's clinical response and laboratory parameters.
Side Effects
Adverse reactions linked to Synthox therapy are mainly those of hyperthyroidism brought on by therapeutic overdose. They include the following: General: fatigue, increased appetite, weight loss, heat intolerance, fever, excessive sweating. Central nervous system: headache, hyperactivity, nervousness, anxiety, irritability, emotional lability, insomnia. Musculoskeletal: tremors, muscle weakness. Cardiovascular: palpitations, tachycardia, arrhythmias, increased pulse and blood pressure. Respiratory: dyspnea. Gastrointestinal: diarrhea, vomiting, abdominal cramps. Dermatologic: hair loss, flushing.
Cautions & Contraindications
Warnings & Precautions
Some patients have hypothyroidism because their pituitary gland isn't working properly, and they may also have adrenocortical insufficiency. If so, this needs to be treated first with adequate Corticosteroid replacement, before Synthox therapy is started, to prevent acute adrenal insufficiency. Take great care when choosing the starting dose of Synthox, and any later increases, in patients with cardiovascular disease and/or severe, long-existing hypothyroidism. A starting dose that is too high, or an increase that is too rapid, can cause angina complaints to develop or get worse. It can also lead to arrhythmias, myocardial infarction, cardiac failure or a sudden rise in blood pressure, especially in older patients. If the body weight changes markedly during treatment with T4, the dose has to be adjusted. When blood levels of T3 and T4 are being monitored, the doctor should know that a "high" normal to slightly raised T4 level is needed to get a normal T3 level. In primary hypothyroidism, the correct dose of Synthox is generally worked out by checking the serum TSH level to see whether it has returned to normal. This matters because intoxication with Thyroid preparations may have serious consequences.
Contraindications
Levothyroxine Sodium should not be used in untreated subclinical or overt thyrotoxicosis of any cause, in acute myocardial infarction, or in uncorrected adrenal failure.
Pregnancy & Breastfeeding
Pregnancy Category A. Levothyroxine requirements may increase during pregnancy. Although thyroid hormones are excreted only minimally in human milk, caution should be exercised when giving it to a nursing woman. However, adequate replacement doses of Levothyroxine are generally needed to maintain normal lactation.
⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
Overdose
An overdose of Levothyroxine Sodium causes the signs and symptoms of hyperthyroidism. These are agitation, confusion, irritability, hyperactivity, headache, sweating, mydriasis (widened pupils), tachycardia, arrhythmias, tachypnoea, pyrexia, increased bowel movements and convulsions. Cerebral embolism, shock, coma and death have also been reported.
The symptoms may not be obvious, and they may not appear until several days after the Levothyroxine Sodium was taken. If signs or symptoms of overdosage occur, the dose should be reduced or stopped for a time. Treatment is symptomatic.
⚠️ In an emergency call 999 or go to the nearest hospital emergency department.
Storage
Keep Levothyroxine Sodium in a dry place below 30°C and away from light. Keep it out of the reach of children.
Drug Interactions
Common questions about Thyronor 100 mcg
What is Thyronor 100 mcg Tablet?
Thyronor 100 mcg Tablet is a medicine that contains Levothyroxine Sodium. It is made by Nuvista Pharma PLC. It belongs to the Thyroid drugs & hormone group of medicines.
What is Thyronor used for?
Thyronor is used for: Hypothyroidism, Cancer.
What are the side effects of Thyronor?
Adverse reactions linked to Synthox therapy are mainly those of hyperthyroidism brought on by therapeutic overdose. They include the following: General: fatigue, increased appetite, weight loss, heat intolerance, fever, excessive sweating.
Can I take Thyronor during pregnancy or while breastfeeding?
Pregnancy Category A. Levothyroxine requirements may increase during pregnancy. Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.
What happens if I take too much Thyronor?
An overdose of Levothyroxine Sodium causes the signs and symptoms of hyperthyroidism. These are agitation, confusion, irritability, hyperactivity, headache, sweating, mydriasis (widened pupils), tachycardia, arrhythmias, tachypnoea, pyrexia, increased bowel movements and convulsions. In an emergency call 999 or go to the nearest hospital emergency department.
How should I store Thyronor?
Keep Levothyroxine Sodium in a dry place below 30°C and away from light. Keep it out of the reach of children.
Can I take other medicines with Thyronor?
Some medicines can interact with Levothyroxine Sodium, for example: Calcium Polystyrene Sulfonate, Sertraline, Calcium Lactate Gluconate + Calcium Carbonate + Vitamin C + Vitamin D3, Orlistat, Calcium Orotate, Carbonyl Iron + Folic Acid + Zinc Sulfate. Tell your doctor or pharmacist about every medicine you take.
Is there a cheaper medicine with the same ingredient?
Thyronor is already among the lowest-priced brands of Levothyroxine Sodium at this strength.
Do I need a prescription for Thyronor?
Thyronor is a prescription (Rx) medicine. Take it as your doctor advises.