Iodide-pharmak®

INSTRUCTIONS FOR MEDICAL USE OF THE MEDICINAL PRODUCT IODID-FARMAK® (Iodid-Farmak®)

Composition:

Active substance: potassium iodide;

1 tablet contains potassium iodide equivalent to 130.8 mcg or 261.6 mcg calculated as dry substance, corresponding to iodine 100 mcg or 200 mcg;

Excipients: lactose monohydrate, microcrystalline cellulose, heavy magnesium carbonate, sodium thiosulfate, colloidal anhydrous silicon dioxide, povidone, magnesium stearate.

Pharmaceutical form. Tablets.

Main physicochemical properties: tablets are white or white with a yellowish tint, with a flat surface, a score line and beveled edges.

Pharmacotherapeutic group.

Preparations for the treatment of thyroid disorders. Thyroid agents. Iodine preparations.

ATC code H03C A.

Pharmacological Properties

Pharmacodynamics

Iodid-Farmak® is a preparation of inorganic iodine. Iodine is an essential trace element which is part of thyroid hormones—thyroxine (T4) and triiodothyronine (T3), thus ensuring normal thyroid function.

Upon entering the epithelial cells of thyroid follicles, iodide ions are oxidized by the enzyme iodide-peroxidase to form elemental iodine. This substance undergoes a substitution reaction with the aromatic ring of tyrosine, resulting in the formation of thyronines: the 3,5-diiodinated derivative (the hormone thyroxine, T4) and the 3-iodinated derivative (the hormone triiodothyronine, T3). The thyronines form a complex with the protein thyroglobulin, which is stored in the colloid of the thyroid follicle for several days to weeks. In iodine deficiency, this process is impaired. Iodine supplied in physiological amounts prevents the development of endemic goiter associated with insufficient dietary intake of this element; normalizes thyroid gland size in newborns, children, adolescents, and young adult patients; and influences T3/T4 ratio and TSH levels.

Pharmacokinetics

After oral administration, iodine is almost completely absorbed in the small intestine. Within 2 hours after absorption, it is distributed throughout the extracellular space and accumulates in the thyroid gland, kidneys, stomach, and in breast and salivary glands. The volume of distribution in healthy individuals averages 23 liters (38% of body weight). Plasma concentration after standard dosing ranges from 10 to 50 ng/mL. Iodine concentrations in breast milk, saliva, and gastric juice are approximately 30 times higher than in plasma. The thyroid gland contains about three-quarters (10–20 mg) of the total iodine in the body. Iodine is primarily excreted in urine, and to a lesser extent in feces and exhaled air. At steady-state concentration, the amount of iodine excreted is proportional to the daily intake from food.

Clinical characteristics.

Indications.

Prevention of iodine deficiency development, including during pregnancy or breastfeeding.

Prevention of recurrence of iodine-deficiency goiter after surgical treatment, as well as after completion of combined therapy with thyroid hormones.

Treatment of diffuse euthyroid iodine-deficiency goiter in children, including newborns, and adults.

Contraindications.

Hypersensitivity or history of hypersensitivity to the active substance or other components of the medicinal product. Marked hyperthyroidism. Latent hyperthyroidism at doses exceeding 150 mcg of iodine per day. Presence of autonomous adenoma, as well as focal and diffuse autonomous foci of the thyroid gland at doses from 300 to 1000 mcg of iodine per day (except for preoperative iodine therapy for thyroid blockade according to Plummer). Pulmonary tuberculosis. Hemorrhagic diathesis. Dermatitis herpetiformis Duhring (Duhring-Brocq syndrome).

Interaction with other medicinal products and other types of interactions.

Iodine deficiency enhances the response to antithyroid therapy, whereas iodine excess reduces it; therefore, administration of iodine should be avoided, if possible, before or during treatment of hyperthyroidism. Antithyroid medicinal products inhibit the conversion of iodide into organic compounds in the thyroid gland and thus may induce goiter formation.

Substances absorbed by the thyroid gland via the same "trapping" mechanism as iodide may competitively inhibit iodine uptake by the thyroid gland (e.g., perchlorate, which additionally inhibits intrathyroidal iodide recycling). Medicinal products that are not themselves absorbed may also inhibit iodine uptake, such as thiocyanate at concentrations above 5 mg/dL.

Iodine uptake by the thyroid gland and iodine metabolism within the gland are stimulated by endogenous and exogenous thyroid-stimulating hormone (TSH).

Concomitant treatment with high doses of iodine, which suppress thyroid hormone secretion, and lithium salts may promote the development of goiter and hypothyroidism.

High doses of potassium iodide in combination with potassium-sparing diuretics may cause hyperkalemia.

Concomitant use leads to enhanced cardiac effects of quinidine due to increased potassium concentration in blood plasma.

Simultaneous administration with plant alkaloids and heavy metal salts may result in formation of an insoluble precipitate and impair iodine absorption.

Special precautions for use.

The drug should not be used in hypothyroidism, except in cases where hypothyroidism is caused by iodine deficiency. Administration of iodine should be avoided during therapy with radioactive iodine, or in the presence or suspicion of thyroid carcinoma. It should be taken into account that treatment with this drug in patients with renal insufficiency may lead to the development of hyperkalemia.

The drug Iodid-Farmak® contains lactose. Iodid-Farmak® should not be administered to patients suffering from rare hereditary disorders of galactose intolerance, lactase deficiency, or glucose-galactose malabsorption syndrome.

Use during pregnancy or breastfeeding.

During pregnancy or breastfeeding, the requirement for iodine is increased; therefore, adequate iodine intake (250 mcg per day) is particularly important. Due to the ability of iodine to cross the placenta and the fetus's sensitivity to pharmacologically active doses of the drug, it should be used only at recommended doses. This also applies to the breastfeeding period, as the concentration of iodine in breast milk is 30 times higher than in blood serum. The exception is high-dose iodine prophylaxis administered after nuclear accidents.

Ability to affect reaction speed when driving or operating machinery. No effect.

Dosage and Administration

Prevention of iodine deficiency and endemic goiter (in cases where the daily iodine intake in adults is less than 150–200 mcg/day).

Infants and children under 12 years of age: 50–100 mcg of iodine per day (½–1 tablet of Iodid-Farmak®). To achieve a 50 mcg dose of iodine, medicinal products with appropriate active ingredient content should be used.

Children from 12 years of age and adults: 100–200 mcg of iodine per day (1–2 tablets of Iodid-Farmak®).

Pregnancy or breastfeeding: 200 mcg of iodine per day (1–2 tablets of Iodid-Farmak®).

Prevention of recurrence of iodine-deficiency goiter after surgical treatment, as well as after completion of combined therapy with thyroid hormones.

Children and adults: 100–200 mcg of iodine per day (1–2 tablets of Iodid-Farmak®).

Treatment of diffuse euthyroid iodine-deficiency goiter.

Infants and children: 100–200 mcg of iodine per day (1–2 tablets of Iodid-Farmak®).

Adults: 300–500 mcg of iodine per day (from 1½ to 5 tablets of Iodid-Farmak®).

Administration method.

Tablets should be taken after meals with sufficient liquid, for example a glass of water. For infants and children under 3 years of age, the tablet may be crushed and mixed with food. Prophylactic use of the drug is generally carried out for several months or years, and more often throughout life. For treatment of goiter in newborns, 2–4 weeks is usually sufficient; in children and adults, treatment lasts 6–12 months or longer. The dosage and duration of administration for prophylactic purposes or for treatment of thyroid disorders should be determined individually by a physician.

Children. The drug may be administered to children.

Overdose.

Symptoms of intoxication: brown discoloration of mucous membranes, reflex vomiting (blue-colored vomit if starch is present in food), abdominal pain, diarrhea (possibly with blood in stools), dehydration, and shock. In isolated cases, esophageal strictures have been reported. Fatal cases have occurred. In individual cases, chronic overdose may lead to so-called "iodism," i.e., iodine intoxication: metallic taste in the mouth, swelling and irritation of mucous membranes (rhinitis, conjunctivitis, gastroenteritis, bronchitis). Iodide may activate latent inflammatory conditions such as tuberculosis. Development of edema, erythema, acneiform and bullous rashes, hemorrhages, urticaria, and nervous excitement are possible.

Treatment.

Treatment of acute intoxication: gastric lavage with starch solution, egg white, or 5% sodium thiosulfate solution until all traces of iodine are removed. Symptomatic therapy should be administered to normalize fluid and electrolyte balance; if necessary, anti-shock therapy should be initiated.

Treatment of chronic intoxication: discontinue iodine.

Hypothyroidism caused by iodine intake: discontinue iodine; prescribe thyroid hormones to normalize metabolism.

Hyperthyroidism caused by iodine intake: this is not an overdose in the literal sense, as hyperthyroidism may also occur with iodine amounts considered physiological in other countries.

Treatment depends on the clinical presentation: mild forms usually do not require treatment; in pronounced cases, antithyroid therapy is used (its effectiveness manifests with a delay). In severe cases (thyrotoxic crisis), intensive therapy, plasmapheresis, or thyroidectomy are required.

Side effects.

When iodide is used prophylactically at any age, as well as therapeutically in infants, children, and adolescents, adverse effects are generally not observed. However, in the presence of large autonomous foci in the thyroid gland and when administering iodine in daily doses exceeding 150 mcg, the occurrence of pronounced hyperthyroidism cannot be completely ruled out.

The following side effects occurred with the stated frequency: very common (≥ 1/10); common (≥ 1/100 to < 1/10); uncommon (≥ 1/1000 to < 1/100); rare (≥ 1/10,000 to < 1/1000); very rare (< 1/10,000); unknown (cannot be estimated based on available data).

Endocrine system disorders: very rare: during treatment of diffuse euthyroid iodine-deficiency goiter in adults (daily dose of 300 to 1000 mcg of iodine), iodine-induced hyperthyroidism may occur in individual cases. The main predisposing factor is the presence of diffuse or localized areas of thyroid autonomy. This primarily affects elderly patients who have had goiter for a long time.

Immune system disorders: very rare: hypersensitivity reactions (such as iodine-induced rhinitis, bullous or tuberous iododerma, exfoliative dermatitis, angioneurotic edema, fever, acne, and salivary gland swelling).
Also possible: symptoms of iodism (such as mucosal swelling of the nose, urticaria, Quincke's edema, skin rashes, itching, in isolated cases – anaphylactic shock), eosinophilia, tachycardia, tremor, irritability, sleep disturbances, increased sweating, epigastric discomfort, diarrhea. When used in high doses, goiter and hypothyroidism may develop in individual cases.

Shelf life.

5 years.

Do not use the medicinal product after the expiry date stated on the package.

Storage conditions.

Store in a place protected from light and inaccessible to children, at a temperature not exceeding 25°C.

Packaging. 10 tablets in a blister; 5 blisters in a carton.

Availability. Over-the-counter.

Manufacturer.

JSC "Farmak".

Manufacturer's address.

74, Kyrylivska Street, Kyiv, 04080, Ukraine.