POTASSIUM IODIDE G.L. PHARMA Tablet Ref.[51172] Active ingredients: Potassium iodide

Iodine prophylaxis protects against inhaled or ingested radioiodine and has no effect on other ingested radionuclides.

If thyroid carcinoma is suspected, iodine administration should generally be avoided.

The administration of iodine interferes with radioiodine therapy and thyroid diagnostics.

Patients undergoing thyreostatic treatment must continue with such therapy and regularly undergo medical examinations at short intervals.

Patients with thyrotoxicosis treated medically, or patients with a past history of thyrotoxicosis treated medically who are now off treatment and apparently in remission, may be at risk.

The risk of iodine induced hyperthyroidism may be increased in patients with asymptomatic nodular goitre or latent Graves' disease, who are not under medical care.

Pharmacological doses of iodine may cause thyroid enlargement, which in turn may aggravate airway constriction.

Potassium salts should be given cautiously to patients with renal or adrenal insufficiency, acute dehydration or heat cramp.

Care should be exercised if potassium salts are given concomitantly with potassium-sparing diuretics, as hyperkalaemia may result.

In cases of exposure to radioiodine from nuclear accidents, dosing of potassium iodide should be based on emergency plans and predetermined operational intervention levels. Risk benefit of administration of stable iodine should be weighed for the different age groups at risk.

The groups most likely to benefit from treatment with iodine tablets after exposure to radioactive iodine are children, adolescents, and pregnant and breast-feeding women as well as people living in iodine deficient areas (who are more likely to be affected by exposure to radioactive iodine). If the supply of stable iodine is limited, priority should be given to children and younger adults.

Adults over 40 years of age are less likely to benefit from treatment with iodine tablets after exposure to radioactive iodine. However, individuals at risk of exposure to high doses of radioactive iodine (e.g. emergency workers involved in rescue or clean-up operations) are likely to benefit from treatment irrespective of their age and should be given priority.

Neonates in the first days of life are at particular risk from exposure to radioactive iodine and blocking of thyroid function by overload of potassium iodide. The fraction of radioactive uptake is fourfold greater than in all other age groups. The neonatal thyroid is especially sensitive to functional blocking caused by overload of potassium iodide. Transient hypothyroidism during this early period of brain development can result in loss of intellectual capacity. If stable iodine is given to neonates close follow up of thyroid function is essential. For neonates who have been administered potassium iodide in the first few weeks of life TSH levels and, if necessary, T4 levels should be monitored and appropriate replacement therapy given.

This medicine contains lactose. Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine.

Iodine administration interferes with radioiodine therapy and thyroid diagnostics (see section 4.4).

Several drugs, such as captopril and enalapril can cause hyperkalaemia and this effect may be enhanced if potassium iodide is also administered.

The effect of quinidine on the heart is increased by increased plasma concentration of potassium.

Potassium salts given concomitantly with potassium-sparing diuretics such as amiloride or triamterene or aldosterone antagonists may cause hyperkalaemia (see section 4.4).

Pregnancy

Repeated administration of iodine during pregnancy may suppress foetal thyroid function. Reproductive toxicity has been established in animal studies. Therefore, pregnant women should not receive more than one dose (see section 4.2). If iodine is taken in late pregnancy it is recommended to monitor the thyroid function of the newborn.

Breast-feeding

Iodine is being excreted into breast milk in large amounts, but these amounts are too small to protect the baby sufficiently. Thus the baby has to be given iodine tablets as well. If the intake during breast-feeding is necessary, breast-feeding women should not receive more than one dose (see section 4.2).

Not relevant.

Very common (≥1/10), Common (≥1/100 to <1/10), Uncommon (≥1/1 000 to <1/100), Rare (≥1/10 000 to <1/1 000), Very rare (<1/10 000), Not known (cannot be estimated from the available data).

Immune system disorders

Not known: Hypersensitivity reactions such as swolen salivary glands, headache, bronchospasm and gastro-intestinal disturbances can be mild or severe and may be dose dependent.

Endocrinde disorders

Not known: Iodine-induced autoimmunity (Grave’s and Hashimoto type), toxic nodular goitre and iodine-induced transient hyper- or hypothyroidism have been reported as side effects of iodine therapy.

An overactive thyroid gland, thyroiditis, and an enlarged thyroid gland with or without development or myxoedema have also been reported.

Psychiatric disorders

Not known: Continued administration may lead to mental depression, nervousness, sexual impotence and insomnia.

Gastrointestinal disorders

Not known: sialadenitis, gastrointestinal disturbances

Skin disorders

Rare: temporary skin rash

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via HPRA Pharmacovigilance, Earlsfort Terrace, IRL – Dublin 2; Tel: +353 1 6764971; Fax: +353 1 6762517. Website: www.hpra.ie; E-mail: medsafety@hpra.ie.

Not applicable.