Potassium iodide (KI) is a chemical compound that consists of potassium and iodine. It is commonly used for various purposes:

• Radiation Protection: Potassium iodide is used to protect the thyroid gland from radioactive iodine in the event of a nuclear accident or emergency. The thyroid gland absorbs iodine, including radioactive iodine, which can increase the risk of thyroid cancer. By saturating the thyroid with stable iodine (potassium iodide), it reduces the absorption of radioactive iodine.
• Nutritional Supplement: Potassium iodide is also used as a nutritional supplement to prevent iodine deficiency, which can lead to thyroid problems such as goiter, hypothyroidism, and developmental issues.
• Chemical Reagent: In laboratories, potassium iodide is used as a reagent in various chemical reactions.
• Photography: Potassium iodide is used in photography, particularly in the wet plate collodion process, as a sensitizing agent for preparing photographic emulsions.
• Analytical Chemistry: It is used in analytical chemistry as a source of iodine in iodometry.
• Thyroid Function Tests: Potassium iodide is used in thyroid function tests to assess the health of the thyroid gland.

Potassium iodide is non-radioactive iodine-containing salt that prevents the absorption of radioactive iodine in the thyroid gland preventing it from radiation injury.

Potassium iodide Uses:

• Antidote:
  • It leads to blockage of radioactive isotopes of iodine in thyroid in a nuclear radiation emergency.
• Expectorant:
  • It is also advised as an expectorant for the symptomatic treatment of chronic lung diseases complicated by mucous.
• Off Label Use of Potassium iodide in Adults:
  • Graves hyperthyroidism (following radioactive iodine therapy);
  • Sporotrichosis (cutaneous and lymphocutaneous);
  • Thyroidectomy preparation in patients with Graves disease;
  • Thyroid gland protection during radiopharmaceutical use;
  • Thyrotoxic crisis and thyroid storm

Potassium Iodide dosage in adults:

Expectorant (SSKI):

• Potassium iodide, also known as SSKI when used as an expectorant, is a medication taken by mouth.
• The usual dosage for adults is between 300 to 600 milligrams, which is about 0.3 to 0.6 milliliters, taken 3 to 4 times a day.
• This medication helps to loosen and clear mucus from the lungs and airways, making it easier to cough it up.
• It's commonly used to treat conditions like chronic bronchitis and chronic obstructive pulmonary disease (COPD).

Potassium iodide Dose as Antidote [thyroid block following nuclear radiation emergency (iOSAT, ThyroSafe, ThyroShield)]:

• In case of a nuclear radiation emergency, potassium iodide can be used as an antidote to protect the thyroid gland from absorbing harmful radioactive iodine.
• This medication is available under different brand names like iOSAT, ThyroSafe, and ThyroShield.
• The recommended dosage for both pregnant and lactating women, as well as other adults, is 130 milligrams taken orally once daily.
• This dosage should be continued for 10 to 14 days or as directed by public health officials.
• It's essential to continue taking the medication until the risk of exposure to radioactive iodine has passed or until other protective measures are implemented.
• Following these guidelines helps to safeguard the thyroid gland and reduce the risk of thyroid cancer due to exposure to radioactive iodine during a nuclear radiation emergency.

Potassium iodide Treatment dosage of Thyroidectomy preparation in patients with Graves disease (off-label):

• The typical dosage is between 50 to 100 milligrams, which is about 1 to 2 drops or 0.05 to 0.1 milliliters of SSKI, taken orally three times a day.
• This treatment should be administered for 10 days leading up to the scheduled surgery.
• If the patient's thyroid function hasn't normalized before surgery, it's recommended to consider using beta-blockers like propranolol in the immediate period before surgery.
• Beta-blockers help to reduce the risk of a thyroid storm, a potentially dangerous complication of hyperthyroidism.

Potassium iodide treatment dose of cutaneous and lympho-cutaneous Sporotrichosis:

• The typical dosage starts with an initial dose of 5 drops taken orally three times a day.
• This dosage can then be gradually increased to 40 to 50 drops three times daily as tolerated by the patient.
• This increased dosage should be maintained until 2 to 4 weeks after the lesions have resolved.
• The usual duration of treatment ranges from 3 to 6 months.

Potassium iodide Treatment dose of Thyroid gland protection during radiopharmaceutical use (off-label):

• The dosage typically ranges from 130 to 300 milligrams per day, which is approximately equivalent to 3 to 6 drops of SSKI solution.
• This protective treatment should begin 1 to 48 hours before exposure to the radiopharmaceutical and should be continued afterward until the risk of exposure has diminished.
• The specific duration and timing of initiation may vary depending on the radiopharmaceutical being used, so it's essential to consult the specific protocol and guidelines provided.
• Following these instructions helps to minimize the absorption of radioactive iodine by the thyroid gland, reducing the risk of potential adverse effects associated with radiation exposure.

Potassium Iodide for the treatment of Thyrotoxic crisis and thyroid storm (off-label):

• Administer potassium iodide orally, at least 1 hour after the administration of antithyroid drugs like propylthiouracil or methimazole.
• The typical dosage is SSKI 250 milligrams, which is equivalent to approximately 5 drops or 0.25 milliliters, every 6 hours.

This treatment aims to help stabilize thyroid function and alleviate symptoms associated with thyrotoxic crisis.

Potassium Iodide dosage in children:

Potassium Iodide for the treatment of cutaneous Sporotrichosis:

In children and adolescents, the dosing of potassium iodide (SSKI) should be carefully managed.

• Initial dose: 50 milligrams, equivalent to approximately 1 drop or 0.05 milliliters, taken orally three times daily.
• The dosage can be increased gradually as tolerated, up to a maximum of ≤50 milligrams per kilogram per dose, also approximately ≤1 drop per kilogram per dose or ≤0.05 milliliters per kilogram per dose, three times daily.
• The maximum total dose should not exceed 2500 milligrams per dose (approximately 50 drops or 2.5 milliliters per dose).
• Continue treatment at the maximum tolerated dosage for several weeks after the lesions have resolved.

It's important to start with a low initial dose and gradually increase it as tolerated to minimize the risk of adverse effects. Additionally, close monitoring of the patient's response and any potential side effects is crucial throughout the treatment period.

Potassium Iodide for the treatment of Thyroid block following nuclear radiation emergency: Iosat, ThyroSafe, ThyroShield

• Infants and Children ≤ 3 years:
  • 32.5 milligrams once daily
• Children > 3 to 12 years:
  • 65 milligrams once daily
• Adolescents:
  • For adolescents weighing less than 68 kilograms: 65 milligrams once daily
  • For adolescents weighing 68 kilograms or more: 130 milligrams once daily

It's crucial to continue the treatment until the risk of exposure has passed or until other protective measures such as evacuation, sheltering, or controlling the food and milk supply have been successfully implemented.

Potassium Iodide for the treatment of Thyroid gland protection during radiopharmaceutical use: 

• Age-based dosing (from Olivier, 2003):
  • Infants and Children under 3 years: 32 milligrams once daily
  • Children and Adolescents aged 3 to 13 years: 65 milligrams once daily
  • Adolescents over 13 years: 130 milligrams once daily
• Weight-based dosing (from Giammarile, 2008):
  • Less than 5 kilograms: 16 milligrams once daily
  • 5 to less than 15 kilograms: 32 milligrams once daily
  • 15 to less than 50 kilograms: 65 milligrams once daily
  • 50 kilograms or more: 130 milligrams once daily

It's important to start taking potassium iodide between 1 to 48 hours before exposure to radiation medicine and continue taking it until the risk of exposure has gone down. The exact timing and duration of treatment depend on the specific radiation medicine used.

Potassium Iodide for the preoperative preparation of Thyroidectomy:

• Medication: SSKI (potassium iodide)
• Dosage:
  • 150 to 350 milligrams, which is approximately 3 to 7 drops or 0.15 to 0.35 milliliters, taken orally three times daily.
• Duration: Administered for 10 days before the scheduled surgery.
• Additional consideration: If the patient's thyroid function hasn't normalized before surgery, it's recommended to consider using a beta-blocker like propranolol in the immediate period before surgery. Beta-blockers help reduce the risk of a thyroid storm, which is a potentially dangerous complication of hyperthyroidism.

Potassium Iodide for the treatment of Thyrotoxic crisis and thyroid storm: 

• Infants:
  • SSKI (potassium iodide) Oral: 100 milligrams, which is approximately 2 drops or 0.1 milliliters, taken orally four times daily.
• Children and Adolescents:
  • SSKI (potassium iodide) Oral: 250 milligrams, which is approximately 5 drops or 0.25 milliliters, taken orally two to four times daily.

It's important to administer potassium iodide at least 1 hour after the administration of antithyroid drugs like methimazole. This treatment helps to stabilize thyroid function and alleviate symptoms associated with thyrotoxic crisis or thyroid storm.

Pregnancy Risk Factor D

• During pregnancy, potassium iodide poses a risk to the fetus as it can cross the placenta, potentially leading to hypothyroidism and goiter in the newborn.
• Using it as an expectorant during pregnancy is not recommended by the American Academy of Pediatrics (AAP).
• However, its use for protecting against thyroid cancer due to exposure to radioactive iodine is considered acceptable, weighing the risks against the benefits, with careful consideration of the dosage and duration.
• When it comes to using antidotes like potassium iodide during pregnancy, it's essential to prioritize the mother's health and prognosis, administering them if necessary while consulting with a physician.
• Pregnant women should follow instructions from public health officials and contact their physician for guidance.
• It's advisable to avoid repeat dosing if possible, and additional information can be found in the iodine monograph.

Potassium iodide use during breastfeeding:

• Potassium iodide can pass into breast milk, potentially causing skin rash and thyroid suppression in the nursing infant.
• Nursing mothers should follow instructions from public health officials regarding its use and consult their physician.
• It's essential to be cautious about its usage during breastfeeding to avoid any adverse effects on the infant.
• For further details, refer to the iodine monograph.

Potassium iodide dose adjustment in renal disease:

• The manufacturer's labeling for potassium iodide doesn't include specific dosage adjustments for individuals with renal impairment.
• However, it's advisable to use potassium iodide with caution in such cases.
• Patients with renal impairment may have reduced kidney function, which can affect how their body processes medications.

Potassium iodide dose adjustment in liver disease:

• The manufacturer's labeling for potassium iodide typically does not include specific dosage adjustments for individuals with hepatic (liver) impairment.

Side effects of potassium iodide:

• Cardiovascular:
  • Cardiac Arrhythmias
  • Numbness
  • Vasculitis
• Central Nervous System:
  • Confusion
  • Fatigue
  • Fever
  • Numbness
  • Tingling Sensation
• Dermatologic:
  • Acne Vulgaris
  • Dermatitis
  • Urticaria
• Endocrine & Metabolic:
  • Goiter
  • Hyperthyroidism (Prolonged Use)
  • Hypothyroidism (Prolonged Use)
  • Myxedema
• Gastrointestinal:
  • Diarrhea
  • Enlargement Of Salivary Glands
  • Gastric Distress
  • Gastrointestinal Hemorrhage
  • Gingival Pain
  • Metallic Taste
  • Nausea
  • Stomach Pain
  • Toothache
  • Vomiting
• Hematologic & Oncologic:
  • Eosinophilia
  • Lymphedema
  • Thyroid Adenoma
• Hypersensitivity:
  • Hypersensitivity Reaction (Angioedema
  • Cutaneous And Mucosal Hemorrhage
  • Serum Sickness-Like Symptoms)
• Neuromuscular & Skeletal:
  • Arthralgia
  • Weakness
• Respiratory:
  • Dyspnea
  • Rhinitis
  • Wheezing
• Miscellaneous:
  • Iodine Poisoning (With Prolonged Treatment/High Doses)

Contraindication to Potassium iodide:

• Potassium iodide should not be used in individuals who have hypersensitivity to iodide, iodine, or any component of the formulation.
• Additionally, it is contraindicated in patients with dermatitis herpetiformis, hypocomplementemic vasculitis, and nodular thyroid conditions with heart disease.

Warnings and precautions

Hypersensitivity

• Some individuals may experience allergic reactions to potassium iodide, presenting as angioedema (swelling), cutaneous/mucosal hemorrhage, and symptoms resembling serum sickness such as fever, joint pain, enlarged lymph nodes, and increased levels of eosinophils.

Reactions to skin:

• Potassium iodide can lead to flare-ups of acne and/or dermatitis, causing skin issues.

Thyroid adverse effects:

• Prolonged use may result in hypothyroidism.
• It can also cause either an underactive or overactive thyroid, along with thyroid enlargement.
• It's essential to be cautious in patients with a history of hyperthyroidism, and potassium iodide should not be used in those with nodular thyroid conditions (goiter) and heart disease.
• High doses or prolonged treatment may lead to iodism or chronic iodide poisoning, presenting symptoms such as mouth/throat burning, sore teeth/gums, severe headache, metallic taste, eye irritation/swelling, increased salivation, acne-like skin lesions, and occasionally severe skin lesions.
• Treatment should be stopped, and supportive care initiated in such cases.

Insufficiency of the adrenal glands:

• Patients with Addison's disease should use potassium iodide cautiously.

Bronchitis

• Caution should be exercised when using potassium iodide in patients with acute bronchitis.

Cardiac disease

• Patients with cardiac issues should use potassium iodide cautiously.

Myotonia congenita:

• Use with caution in patients with myotonia congenita, a neuromuscular disorder.

Renal impairment

• Potassium iodide should be used cautiously in patients with renal impairment, as their kidney function may affect how the medication is processed.

Tuberculosis

• Use with caution in patients with tuberculosis, a bacterial infection affecting the lungs.

Potassium iodide (SSKI, Thyroshield): Drug Interaction

Risk Factor C (Monitor therapy)
Aliskiren	Potassium Salts may enhance the hyperkalemic effect of Aliskiren.
Angiotensin II Receptor Blockers:	Potassium Salts may enhance the hyperkalemic effect of Angiotensin II Receptor Blockers.
Angiotensin-Converting Enzyme Inhibitors	Potassium Salts may enhance the hyperkalemic effect of Angiotensin-Converting Enzyme Inhibitors.
Cardiac Glycosides	Antithyroid Agents may increase the serum concentration of Cardiac Glycosides.
Drospirenone	Potassium Salts may enhance the hyperkalemic effect of Drospirenone.
Heparin	May enhance the hyperkalemic effect of Potassium Salts.
Heparins (Low Molecular Weight)	May enhance the hyperkalemic effect of Potassium Salts.
Lithium	Potassium Iodide may enhance the hypothyroid effect of Lithium. Risk C: Monitor therapy
Nicorandil	May enhance the hyperkalemic effect of Potassium Salts.
Theophylline Derivatives	Antithyroid Agents may increase the serum concentration of Theophylline Derivatives. Exceptions: Dyphylline.
Risk Factor D (Consider therapy modification)
Eplerenone	May enhance the hyperkalemic effect of Potassium Salts. Management: This combination is contraindicated in patients receiving eplerenone for treatment of hypertension.
Potassium-Sparing Diuretics	Potassium Salts may enhance the hyperkalemic effect of Potassium-Sparing Diuretics.
Vitamin K Antagonists (eg, warfarin)	Antithyroid Agents may diminish the anticoagulant effect of Vitamin K Antagonists.
Risk Factor X (Avoid combination)
Sodium Iodide I131	Antithyroid Agents may diminish the therapeutic effect of Sodium Iodide I131. Management: Discontinue antithyroid therapy 3-4 days prior to sodium iodide I-131 administration.

Monitoring parameters:

Thyroid Function Monitoring

• Pregnancy and Breastfeeding: Thyroid function should be regularly monitored in pregnant or breastfeeding women who require repeat doses following exposure to radioactive iodine. This monitoring helps ensure that the thyroid gland is functioning within normal parameters and that any abnormalities can be promptly addressed.
• Neonates and Young Infants: Similarly, thyroid function should be monitored in neonates and young infants who need repeat doses after exposure to radioactive iodine. These age groups are particularly vulnerable to thyroid-related issues, and close monitoring is essential to detect any abnormalities early.

Signs and Symptoms of Thyroid Dysfunction

It's important to be vigilant for signs and symptoms of both hypo- and hyperthyroidism, which may indicate thyroid dysfunction:

• Hypothyroidism: Symptoms may include fatigue, weight gain, cold intolerance, dry skin, constipation, and depression. In infants, symptoms may also include poor feeding, jaundice, and developmental delay.
• Hyperthyroidism: Symptoms may include weight loss, increased appetite, heat intolerance, sweating, palpitations, tremors, anxiety, and irritability. In infants, symptoms may also include poor weight gain, irritability, and difficulty sleeping.

Regular monitoring of thyroid function and awareness of potential symptoms allow for timely intervention and management of thyroid disorders, promoting optimal health outcomes for individuals exposed to radioactive iodine.

How to administer Potassium iodide?

• SSKI: Dilute the dose in a glassful of water, fruit juice, or milk. It's recommended to take it with food or milk to reduce the likelihood of gastric irritation.
• iOSAT, ThyroSafe, ThyroShield: Take the medication as soon as advised by public officials during emergencies. Do not exceed one dose in a 24-hour period. Tablets can be taken whole or crushed and mixed with various liquids such as water, low-fat milk (white or chocolate), orange juice, flat soda, raspberry syrup, or infant formula. Raspberry syrup may help disguise the taste better, as potassium iodide has a salty taste that may not be fully masked by water or low-fat milk.

These administration instructions aim to make taking potassium iodide more manageable, especially during emergencies.

Mechanism of action of Potassium iodide:

• Potassium iodide works in two main ways: first, it makes mucus thinner by increasing the amount of liquid in the respiratory tract, making it easier to cough up; second, it slows down the production of thyroid hormone and helps build up a substance called colloid in the thyroid glands.
• In cases of exposure to radioactive iodine, like during a nuclear accident, potassium iodide can help by blocking the thyroid from absorbing the harmful radioactive iodine, which lowers the chances of getting thyroid cancer.

The beginning of action:

• When treating hyperthyroidism, potassium iodide typically starts working within 24 to 48 hours after the initial dose is taken.

Peak effect:

• Continuous therapy with potassium iodide for hyperthyroidism reaches its peak effectiveness around 2 weeks after starting the treatment.

Duration:

• In cases of exposure to radioactive iodine, each dose of potassium iodide provides protection for approximately 24 hours.
• This means that the protective effects of the medication last for about a day before another dose is needed.

International Brands of Potassium iodide:

• iOSAT
• SSKI
• ThyroSafe
• Cato-Bell
• Iodid
• Iodure de Potassium
• Ioduro Potasico Rovi
• Jodam
• Jodetten Henning
• Jodgamma
• Jodid
• Jodid Merck
• Jodid Verla
• Jodid-ratiopharm
• Jodix
• Jodostin
• Jodox
• Kalium jodatum
• Kaliumiodid
• Kaliumiodid BC
• Kaliumjodid Lannacher
• Kaliumjodid Recip
• Kaliumjodid ”Dak”
• Kaliumjodide G. L.
• Mono-Jod
• Tarjod
• Thyroprotect

Potassium iodide brand names in Pakistan:

Brands will be updated later. Important brand names include Lugols iodine solution and tincture iodine.