Thyrozol 5 : Each film-coated tablet contains Thiamazole 5 mg
Thyrozol 10 : Each film-coated tablet contains Thiamazole 10 mg
Mode of action
Thiamazole inhibits dose-dependently the incorporation of iodine into tyrosine and thereby the neo-synthesis of thyroid hormones. This property permits symptomatic therapy of hyperthyroidism regardless of its cause.
Whether thiamazole furthermore affects the "natural course" taken by the immunologically induced type of hyperthyroidism (Graves disease), i.e. whether it suppresses the underlying immunepathogenetic process, can presently not be decided with certainty. The release of previously synthesised thyroid hormones from the thyroid is not affected. This explains why the length of the latency period until normalization of the serum concentrations of thyroxine and triiodothyronine, and thus to clinical improvement, differs in individual cases.
Hyperthyroidism is also unaffected by the release of hormones after destruction of the thyroid cells, e.g. after radioiodine therapy or in thyroiditis.
- Drug treatment of hyperthyroidism, especially in slight or absent thyroid enlargement (goiter) as well as in younger patients
- Preparation for surgery in all forms of hyperthyroidism
- Preparation of patients with hyperthyroidism for planned radioiodine treatment to prevent the risk of a thyrotoxic crisis after therapy.
Conservative treatment of hyperthyroidism:
Two different dosage regimens are recommended:
- Complete blocking of thyroid hormone production is achieved with daily doses of 25 to at the most 40 mg thiamazole.
Initial therapy: (to achieve normal metabolic activity of the thyroid gland):
Maximum daily dose : 40 mg thiamazole in single doses of maximally 20 mg thiamazole, depending on the severity of the disease.
2 times 1 tablet Thyrozol 10 mg (20 mg)-mild cases
2 times 1 tablet Thyrozol 20 mg (40 mg) - severe cases.
After normalization of the thyroid function (generally between weeks 3 and 8) the dose is stepwise reduced in long-term treatment to a maintenance dose of 5 to 20 mg daily. This dosage usually requires the additional administration of thyroid hormones.
- In therapy with Thyrozol alone the dose depends on metabolic activity which must be checked individually in each patient, paying particular attention to the TSH (= Thyroid Stimulating Hormone) values. The dose is in this case between 2.5 and 10 mg per day.
Iodine-induced hyperthyroidism may possibly require higher doses.
Normal metabolic activity of the thyroid gland is attained, as described above. Surgery should be performed as soon as normal function is achieved. Otherwise, supplementary thyroid hormones must be administered. In the last 10 days before surgery, the surgeon may prefer to administer iodine to consolidate the thyroid tissue.
Treatment before radioiodine therapy:
Normal metabolic activity of the thyroid gland is attained, as described above.
Thyrozol reduces the biological half-life of iodine in the thyroid tissue. Therefore, higher radioiodine doses may be necessary.
Dosage in children:
Initial dose depending on the severity of the disease: 0.3 - 0.5 mg/kg body weight per day.
Maintenance dose: 0.2 - 0.3 mg/kg body weight per day.
Additional treatment with thyroid hormone may be required.
In pregnant women as low dose as possible 2.5 - 10 mg per day should be selected and treatment be carried out without the additional administration of thyroid hormone.
In patient with liver damage the dose should be kept as low as possible.
In initial therapy of hyperthyroidism, the above specified single doses should be taken at regular intervals throughout the day. The maintenance dose can be taken all at once in the morning after breakfast.
Take Thyrozol tablets whole with some liquid (e.g. ½ glass of water) after meals.
In conservative treatment of hyperthyroidism therapy with Thyrozol is usually continued over a period of 6 months to 2 years (1 year on average). Statistically, the probability of remission increases with the duration of therapy.
When preparing patients with hyperthyroidism for surgery, treatment with Thyrozol can be commenced about 3-4 weeks prior to the scheduled time of operation (or earlier in individual cases) and discontinued on the day before surgery.
When used in preparing patients with autonomous adenoma or latent hyperthyroidism for a required exposure to iodine, the duration of treatment with Thyrozol depends on the time the iodine-containing substance is retained in the body.
Patients with considerably enlarged thyroid glands and constriction of the trachea should only undergo short-term treatment with Thyrozol, since long-term administration can result in further thyroid growth, which is associated with the risk of further constriction of the airways. Where necessary, treatment must be monitored particularly carefully. The treatment is preferably combined with thyroid hormones.
Agranulocytosis is potentially a serious side effect. Patients should be instructed to report to their physicians any symptoms of agranulocytosis, such as fever or sore throat. Leucopenia, thrombocytopenia, and aplastic anemia (pancytopenia) may also occur. The drug should be discontinued in the presence of agranulocytosis, aplastic anemia (pancytopenia), hepatitis, or exfoliative dermatitis. The patients bone marrow function should be monitored. Due to the similar hepatic toxicity profiles of methimazole & propylthiouracil, attention is drawn to the severe hepatic reactions which have occurred with both drugs. There have been rare reports of fulminant hepatitis, hepatic necrosis, encephalopathy, and death. Symptoms suggestive of hepatic dysfunction (anorexia, pruritus, right upper quadrant paint, etc.) should prompt evaluation of liver function. Drug treatment should be discontinued promptly in the event of clinically significant evidence of liver abnormality including hepatic transaminase values exceeding 3 times the upper limit of normal. Methimazole can cause fetal harm when administered to a pregnant woman. Methimazole readily crosses the placental membranes and can induce goiter and even creatinism in the developing fetus. In addition, rare instances of aplasia cutis, as manifested by scalp defects, have occurred in infants born to mothers who received methimazole during pregnancy. If pregnant while taking this drug, the patient should be warned of the potential hazard to the fetus. Since scalp defects have not been reported in offspring of patients treated with propylthiouracil, that agent may be preferable to methimazole in pregnant woman requiring treatment with antithyroid drugs.
Post-partum patients receiving methimazole should not nurse their babies.
General: Patients who receive methimazole should be under close surveillance and should be cautioned to report immediately any evidence of illness, particularly sore throat, skin eruptions, fever headache, or general malaise. In such cases, white-blood-cell and differential counts should be made to determine whether agranulocytosis has developed. Particular care should be exercised with patients who are receiving additional drugs known to cause agranulocytosis.
Laboratory tests: Because methimazole may cause hypoprothrombinemia and bleeding, prothrombin time should be monitored during therapy with the drug, especially before surgical procedures. Periodic monitoring thyroid function is warranted, and the finding of an elevated TSH warrants a decrease in the dosage of methimazole.
Carcinogenesis, Mutagenesis, Impairment of fertility: In a 2 year study, rats were given methimazole a doses of 0.5, 3 and 18 mg/kg/day. These doses were 0.3, 2 and 12 times the 15 mg/day maximum human maintenance dose (when calculated on the basis of surface area). Thyroid hyperplasia, adenoma, and carcinoma developed in rats at the two higher doses. The clinical significance of these findings is unclear.
Pregnancy: Methimazole used judiciously is an effective drug in hyperthyroidism complicated by pregnancy. In many pregnant women, the thyroid dysfunction diminishes as the pregnancy proceeds: consequently, a reduction in dosage may be possible. In some instances, use of methimazole can be discontinued 2 or 3 weeks before delivery.
Nursing mothers: The drug appears in human breast milk and its use is contraindicated in nursing mothers (see warnings).
- Minor adverse reactions such as: Allergic skin reactions (itching, redness, rash) of varying degree occur frequently. They mostly take a mild course and frequently recede during continued therapy. Serious courses to the point of generalized dermatitis have been described only in isolated cases. Nausea, vomiting, epigastric distress, arthralgia, paresthesia, loss of taste, abnormal loss of hair, myalgia, headache, pruritus, drowsiness, neuritis, edema, vertigo, skin pigmentation, jaundice, sialadenopathy and lymphadenopathy.
- Drug fever occurs rarely.
- Disturbances in the sense of taste occur rarely; they can recede after discontinuation of Thyrozol, normalization may, however, take several weeks.
- Changes in the blood count, granulocytopenia, thrombocytopenia, aplastic anemia, hypoprothrombinemia and nephritis can occur; agranulocytosis occurs in about 0.3-0.6 % of cases. They become apparent as inflammation of oral mucosa and pharynx, fever, formation of furuncles. In the case that any of these symptoms occur, especially during the first weeks of treatment, patients should discontinue Thyrozol immediately and have their doctor perform a blood count check. The symptoms can still occur weeks or months after the start of therapy. In most cases, they recede spontaneously.
- Isolated cases of pain in the joints have been reported, which generally develop gradually and also after several months of therapy. There are no signs of arthritis.
- Isolated cases of jaundice due to impaired flow of bile or toxic inflammation of the liver have been described.
The symptoms generally recede after discontinuation of the medication.
- The following have been described in isolated cases: inflammation of lymph nodes (lymphadenitis), acute salivary gland swelling, decrease in the number of blood platelets and other blood constituents, inflammation of vessels and nerves, generally impaired sensitivity, loss of hair, Thyrozol-induced lupus erythematosus (autoimmune disease, the symptoms of which disappear after discontinuation of Thyrozol), as well as insulin autoimmune syndrome (with pronounced drop in blood glucose values).
- Thiamazole reduces the energy requirement which was pathologically increased due to hyperthyroidism. This means that, with an unaltered diet, again in body weight can occur during treatment with Thyrozol. This is generally desired from a medical point of view.
- Excessive dosage can cause hypothyroidism as well as diffuse thyroid growth. Consequently, the Thyrozol dose should be reduced after the metabolic activity of the thyroid gland has been normalized and/or a thyroid hormone should be given additionally. It is not appropriate to discontinue Thyrozol completely and continue treatment with thyroid hormones.
- Further growth of the already enlarged thyroid under thiamazole therapy in spite of suppressed TSH-levels (TSH =Thyroid Stimulating Hormone) is a result of the underlying disease and cannot be prevented by additional treatment with thyroid hormones.
- The occurrence or deterioration of an eye disease which is typical in patients with hyperthyroidism (endocrine orbital disease) is largely independent of the course taken by the thyroid disease.
Such a complication, by itself, is no reason to change the treatment regimen and is not to be regarded as a side-effect of thiamazole therapy correctly carried out.
- At low percentage late hypothyroidism can occur after therapy with Thyrozol without any additional surgical measures. This is probably not a side-effect of Thyrozol, but to be regarded as inflammatory process in the thyroid tissue occurring alongside the underlying disease.
Please consult your doctor immediately if you have any side-effects. He or she will take any appropriate counter-measures necessary. If you have symptoms of agranulocytosis, granulocytopenia and thrombocytopenia drug fever or disturbances in the sense of taste, he or she will discontinue treatment with Thyrozol tablets and prescribe a different medication.
It should be noted that about 10 % of patients with untreated hyperthyroidism have leukopenia (white-blood-cell count of less than 4,000/mm3) often with relative granulopenia.
Thyrozol should not be used in known hypersensitivity to thiocarbamide derivatives, patients with changes in the blood count (granulocytopenia), cholestasis existing before the start of therapy, previous damage to bone marrow after treatment with carbimazole or thiamazole.
Thyrozol should only be used under certain conditions and with particular caution in earlier, less serious hypersensitivity reactions (e.g. allergic skin rashes, itching).
Thyrozol should only be used short-term and with careful medical monitoring in considerable enlargement of the thyroid gland with constriction of the trachea because of the risk of thyroid growth.
Methimazole is contraindicated in nursing mothers because the drug is excreted in milk.
Iodine deficiency increases, excess iodine reduces the response of the thyroid gland to Thyrozol. No further direct interactions with other medication are known. It should, however, be noted that m the presence of hyperthyroidism the break-down and excretion of other medication can be accelerated. With increasing normalization of the thyroid function these also return to normal. If necessary, the doctor will have to correct the dosage. The activity of anticoagulants may be potentiated by anti-vitamin-K activity attributed to methimazole.
Store in a dry place, below 25° C
Thyrozol 5 : Box of 10 x 10 film-coated tablets in blisters
Thyrozol 10 : Box of 10 x 10 film-coated tablets in blisters
"Harus dengan resep dokter"
"On medical prescription only"
Merck KGaA, Germany ,
PT.Merck Tbk., Jakarta
Thyrozol 5 : DKI 0063401417A2
Thyrozol 10 : DKI0063401417B2