Microiodid (Tablets) Instructions for Use

ATC Code

H03CA (Iodine preparations)

Active Substance

Potassium iodide (Ph.Eur. European Pharmacopoeia)

Clinical-Pharmacological Group

Iodine preparation for the prevention and treatment of thyroid diseases

Pharmacotherapeutic Group

Drugs for the treatment of thyroid gland diseases; iodine preparations

Pharmacological Action

A product containing inorganic iodine. When iodides enter the cells of the follicular epithelium of the thyroid gland, under the influence of the enzyme iodide peroxidase, iodine is oxidized to form elemental iodine, which is incorporated into the tyrosine molecule. In this case, one part of the tyrosine radicals in thyroglobulin is iodinated. The iodinated tyrosine radicals condense into thyronines, the main ones being thyroxine (T₄) and triiodothyronine (T₃). The resulting complex of thyronine and thyroglobulin is released, as a stored form of the thyroid hormone, into the follicular colloid and remains in this state for several days or weeks. With iodine deficiency, this process is disrupted.

Potassium iodide, compensating for the iodine deficiency, helps restore impaired synthesis of thyroid hormones.

With a normal iodine content in the environment, under the influence of excess iodides, the biosynthesis of thyroid hormones is inhibited, their release from thyroglobulin is reduced, the sensitivity of the thyroid gland to the pituitary thyroid-stimulating hormone is decreased, and its secretion by the pituitary gland is blocked.

Pharmacokinetics

When taken orally, it is rapidly absorbed from the gastrointestinal tract. It is widely distributed in all tissues and body fluids.

Indications

Prevention and treatment of endemic goiter. Prevention of goiter recurrence during complex treatment with thyroid hormone preparations.

ICD codes

Dosage Regimen

Determine the dosage individually based on the indication, patient age, and iodine status.

For prophylaxis of endemic goiter, administer a daily dose of 50-100 mcg iodine for children. For adolescents and adults, administer a daily dose of 100-200 mcg iodine.

For treatment of endemic goiter, the daily dose is typically 100-200 mcg iodine for children. For adolescents and adults, the daily dose is typically 200-300 mcg iodine.

To prevent goiter recurrence after surgical or medical treatment, use a daily dose of 100-200 mcg iodine.

For long-term therapy, monitor thyroid function periodically to adjust the dose and avoid both deficiency and excess.

Administer tablets orally, preferably after a meal with a sufficient amount of water to minimize gastrointestinal irritation.

Do not exceed the maximum recommended daily doses without specific medical supervision due to the risk of adverse effects, including iodine-induced hyperthyroidism or hypothyroidism.

In elderly patients, initiate therapy with caution and at the lower end of the dosing range, monitoring for signs of thyroid dysfunction.

In patients with renal impairment, monitor for potential hyperkalemia, especially during prolonged use.

Adverse Reactions

Manifestations of iodism: swelling of the nasal mucosa, urticaria, angioedema, eosinophilia, shock, tachycardia, irritability, sleep disorders, increased sweating, diarrhea (in patients over 40 years of age); in some cases, when used in doses exceeding 300-1000 mcg/day, the development of hyperthyroidism is possible (especially in elderly patients, in the presence of nodular or diffuse toxic goiter); with high-dose therapy (more than 1 mg/day), iodine-induced goiter and, accordingly, hypothyroidism may develop.

Contraindications

Hypersensitivity to iodine preparations; pronounced hyperthyroidism, latent hyperthyroidism (when used in doses exceeding 150 mcg/day), toxic adenoma, nodular or diffuse toxic goiter (when used in doses of 300-1000 mcg/day), dermatitis herpetiformis (Duhring’s disease), pregnancy and breastfeeding (when used in doses of 1-2 mg/day).

Use in Pregnancy and Lactation

During pregnancy, use is possible only in recommended doses, because iodine penetrates the placental barrier and can cause the development of hypothyroidism and goiter in the fetus.

Iodine is excreted in breast milk. When used by the mother during lactation (breastfeeding) in doses of more than 1 mg/day, there is a risk of developing hypothyroidism in the infant.

Use in Renal Impairment

During therapy in patients with renal insufficiency, the development of hyperkalemia is possible.

Pediatric Use

Can be used in children according to indications in age-appropriate recommended doses and dosage forms.

Geriatric Use

Should be used with caution in elderly patients due to the risk of developing hyperthyroidism in this category of patients.

Special Precautions

During therapy in patients with renal insufficiency, the development of hyperkalemia is possible.

Drug Interactions

With simultaneous high-dose therapy with iodine and potassium-sparing diuretics, the development of hyperkalemia is possible; with lithium preparations – the development of goiter and hypothyroidism. Perchlorate and thiocyanate competitively inhibit the absorption of iodine by the thyroid gland, and TSH stimulates it.

Antithyroid drugs weaken the effect (mutually).

Storage Conditions

Store at 2°C (36°F) to 25°C (77°F). Keep in original packaging, protected from light. Keep out of reach of children.

Dispensing Status

Over-the-Counter

Important Safety Information

This information is for educational purposes only and does not replace professional medical advice. Always consult your doctor before use. Dosage and side effects may vary. Use only as prescribed.