Neomercazole (CARBIMAZOLE) is a drug used to decrease the amount of thyroid hormones produced by the thyroid gland. The thyroid gland uses iodine in the formation of the thyroid hormones, and Neomercazole acts by preventing the body from transforming iodine into its usable form, as well as by inhibiting the combination of transformed iodine with other components that leads to the formation of thyroid hormones. However, Neomercazole does not act on the already existing hormone levels, so it may take up to three or four weeks until the treatment shows results. Typically there are some signs of improvement after one to two weeks, with the best results showing within six to eight weeks from the moment the treatment was started.

Common uses

Neomercazole is usually prescribed for the treatment of an overly active thyroid gland (hyperthyroidism). In some cases, usage of this medicine is enough to return the gland’s functioning to normal, while other cases require combined treatments together with other drugs, or longer treatments to maintain control over the thyroid gland. Neomercazole can also be prescribed in order to reduce the thyroid hormone levels in the body in preparation for a thyroidectomy (removal of all or a part of the thyroid gland through surgery), or in preparation for radioactive iodine treatment.
Carbimazole is used to reduce production of thyroid hormones when excessive amounts are being produced by an overactive thyroid gland (hyperthyroidism). In some people this medicine may be enough to treat the condition and return thyroid function to normal. You may need to take this medicine for several months in order to maintain control of the thyroid gland.

Carbimazole can also be used to lower the amount of thyroid hormones in the body in preparation for surgery to remove all or part of the thyroid gland (thyroidectomy), or in preparation for treatment with radioactive iodine.

Before using

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Directions

• The tablets are to be taken by mouth.
• Always take the tablets as your doctor tells you to.
• The dosage will be decided by your doctor according to your individual
needs, and may be changed at intervals during treatment.
• The usual adult starting dose is one to three 20mg tablets, or four to twelve
5mg tablets each day.
• For children, the usual starting dose is three 5mg tablets each day.
• Once control is achieved your doctor will gradually reduce your dose to one
to three 5mg tablets each day.
Your doctor may decide to add an additional tablet (l-thyroxine), to help
control your condition.
• Each day’s tablets may be divided into two (morning and evening) or three
daily doses (morning, noon and night).
• If you miss a dose take it as soon as you remember. If your next dose is due,
take both doses together.
• Do not change the dosage without consulting your doctor first.
• Some improvement is usually felt within one to three weeks. However, full
beneficial effects usually take four to eight weeks.
• If you take too many tablets or someone else accidentally takes your
medicine, contact your doctor, pharmacist or the nearest hospital straight
away.
• In order to maintain control of the thyroid gland, you may need to continue
to take NeoMercazole tablets for several months. Your doctor will decide
when treatment can be stopped. He may ask you to have occasional blood
tests to help him determine how you are responding to treatment.
• Radio-iodine is another treatment for hyperthyroidism. If you need radioiodine
treatment, your doctor will tell you to stop taking NeoMercazole
temporarily.

Cautions

In rare cases, Neomercazole may cause a drop in blood cell levels. It is best that you stop the treatment at once and notify your personal health care specialist if you experience any of the following: sore throat, mouth ulcers, high temperature, any signs of infections, unexplained bruising or bleeding, tiredness, general feeling of illness. It may be required for you to take a few tests in order to check your general health condition.
Treatment with this drug should be temporarily stopped or reduced if you are following radioactive iodine treatment. You should never take Neomercazole if you allergic to carbimazole or any other similar products. Alternative treatment methods should be considered before starting treatment with this medicine in patients with liver disorders. Consult with your personal health care specialist before starting Neomercazole treatment if you are pregnant or breast feeding. Use of this drug may affect your unborn or nursing child.

Possible side effects

Carbimazole may be given during pregnancy to a thyrotoxic patient, but the smallest effective dose should be used lest overdosage adversely affects the foetus. Carbimazole crosses the placenta and is excreted into the breast milk. Carbimazole may, therefore, cause foetal or neonatal hypothyroidism and goitre.
Adverse effects occur most frequently during the first 8 weeks of treatment.
Side-effects may include rash, pruritis, skin pigmentation, paraesthesias, urticaria, headache, arthralgia, and gastro-intestinal disturbances (including nausea, vomiting and gastric discomfort), and abnormal hair loss.
Drug fever, a lupus-like syndrome, vasculitis and nephritis, and hepatic disorders, most commonly jaundice, and taste disturbances following carbimazole therapy have been reported.
Bone-marrow depression may occur and mild leucopenia is common. Dose-related agranulocytosis has been reported and patients should be warned to report the incidence of mouth ulcers or sore throat, fever, or rashes as they may precede abnormal findings in the blood by several days.
Treatment should be discontinued if there is any clinical or laboratory evidence of neutropenia. Pancytopenia / aplastic anaemia has been reported infrequently, as has thrombocytopenia and hypoprothrombinaemia.
Cross-sensitivity with other anti-thyroid agents may occur.
Isolated cases of myopathy have been reported. Patients experiencing myalgia after the intake of NeoMercazole should have their creatine phosphokinase levels monitored.

If you take too much

Any The symptoms of Neomercazole overdose are not clear yet, but it is known that the consequences can be severe, possibly even lethal. It is best that you follow your doctor’s directions closely, and never attempt to increase the dosage you have been prescribed. However, if you have reasons to believe you are suffering from an overdose with this drug, immediately contact your personal health care specialist or go to the nearest hospital to seek emergency medical attention.

Additional information

The tablets should be stored in the closed container away from heat (do not store above 25ºC).


Drug interactions

People taking digoxin or theophylline may need a gradual decrease in their digoxin or theophylline dose as this medicine returns thyroid function to normal. This is because the dose of these medicines that is needed can be affected by the level of thyroid hormones in the blood.