Skip to Content

Iosat Side Effects

Generic Name: potassium iodide

Note: This document contains side effect information about potassium iodide. Some of the dosage forms listed on this page may not apply to the brand name Iosat.

For the Consumer

Applies to potassium iodide: oral solution

Along with its needed effects, potassium iodide (the active ingredient contained in Iosat) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur while taking potassium iodide:

Less Common

  • Hives
  • joint pain
  • swelling of arms, face, legs, lips, tongue, and/or throat
  • swelling of lymph glands

With long-term use

  • Burning of mouth or throat
  • confusion
  • headache (severe)
  • increased watering of mouth
  • irregular heartbeat
  • metallic taste
  • numbness, tingling, pain or weakness in hands or feet
  • soreness of teeth and gums
  • sores on skin
  • symptoms of head cold
  • unusual tiredness
  • weakness or heaviness of legs

Some side effects of potassium iodide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less Common

For Healthcare Professionals

Applies to potassium iodide: compounding powder, oral liquid, oral solution, oral tablet


Endocrinologic side effects have included both hyper- and hypothyroidism. By inhibiting the release of thyroid hormone from the thyroid gland, iodide can cause goiter and hypothyroidism. This has been called the Wolff-Chaikoff effect, occurring in approximately 4% of patients, and may be more likely in patients with cystic fibrosis (CF). Iodide may induce hyperthyroidism, called the Jod-Basedow effect, when given to patients with preexisting iodide deficiency or autonomous, "hot" thyroid nodules. Iodide can cause parotid gland swelling.[Ref]

In one study of 55 patients with CF who were treated with iodides, 47 developed goiters, and 14 had clinical or laboratory evidence of hypothyroidism. In 2 of the 14 hypothyroidism occurred in the absence of a goiter. Subsequent data are consistent with the possibility that peripheral deiodination of T4 to T3 may be impaired in these patients. Failure to appreciate this can lead to the erroneous diagnosis of congenital hypothyroidism in some patients with CF.[Ref]


The pathogenesis of vegetating iododerma is not clear, may be idiosyncratic, and appears to involve a hyperinflammatory response. Iodides appear to increase the movement of polymorphonuclear leukocytes (PMNLs) into areas of inflammation, enhancing the inflammatory response. Since PMNLs are known to increase connective tissue proliferation, iodides could convert an area of inflammation into an area of proliferative tissue, providing and explanation for proliferative iododermas.[Ref]

Dermatologic side effects have included iododerma in approximately 1% of patients. Iododerma is a term used describe a wide range of dermatologic side effects of KI that typically affect the face, neck, back and upper extremities. Iododerma may present as acneiform vesiculobullous, vesicular, pustular, hemorrhagic or urticarial lesions. The incidence of skin eruptions associated with the use of KI in inpatients from the Boston Collaborative Surveillance Program was less than 0.6%. Rare cases of urticaria, angioedema, polymyalgia, and life-threatening systemic reactions have been associated with the use KI in patients with underlying connective tissue disorders.[Ref]


Rare cases of severe, ulcerative, vegetating iododerma in patients with underlying polyarteritis nodosa, arthritis, lymphoma, subacute glomerulonephritis, multiple myeloma, dermal vasculitis or hypocomplementemia have been reported.[Ref]

Hypersensitivity side effects have included rash, fever, eosinophilia, jaundice, pruritus, angioedema, lymphadenopathy, arthralgia, bronchospasm, submucosal hemorrhage and periarteritis nodosa-type reactions. Bullous iododerma appear to be an allergic reaction, and can be fatal. Other known hypersensitivity reactions to iodides include hematuria, proteinuria, and pulmonary edema. Predisposing risk factors for hypersensitivity reactions appear to include some underlying connective tissue disorders.[Ref]


Gastrointestinal side effects have included "upset stomach" in 10% to 40% of patients, depending on the dose. Other common GI complaints include an unpleasant, "brassy" taste, throat or retrosternal burning, sore gums, and salivation. In rare cases and in cases of overdose, esophagitis and gastritis have been reported.[Ref]


Iodide may interfere with certain autoanalyzer measurements of serum chloride, resulting in falsely elevated values. The "true" anion gap in some cases can, therefore, be higher than the calculated anion gap. "Hyperchloremic acidosis" has been associated with ingestion of KI. In some cases of KI overdose, the anion gap was due to the presence of high serum levels of lactic acid.[Ref]

Metabolic side effects have included metabolic acidosis following KI overdose.[Ref]


Renal side effects have included acute renal failure secondary to tubular necrosis following KI overdose.[Ref]


Hematologic side effects have included rare reports of hemolytic anemia, and appear to be limited to cases of overdose.[Ref]


Immunologic side effects have included rare cases of systemic granulomatous vasculitis.[Ref]

A 37-year-old female with Sweet's syndrome was successfully treated with potassium iodide. Within 12 days after beginning therapy, however, she developed malaise, diminished vision, hypertension, rash, and fever. Physical and laboratory findings revealed new renal insufficiency, bilateral papillitis on retinal examination, and leukocytoclastic vasculitis per skin biopsy. Renal biopsy and renal and mesenteric angiography were normal. The patient's signs and symptoms resolved over 11 months with the addition of oral prednisolone therapy.[Ref]


1. Shopsin B, Shenkman L, Blum M, Hollander CS "Iodine and lithium-induced hypothyroidism. Documentation of synergism." Am J Med 55 (1973): 695-9

2. Lesher JL Jr, Fitch MH, Dunlap DB "Subclinical hypothyroidism during potassium iodide therapy for lymphocutaneous sporotrichosis." Cutis 53 (1994): 128-30

3. Bostanci I, Sarioglu A, Ergin H, Aksit A, Cinbis M, Akalin N "Neonatal goiter caused by expectorant usage." J Pediatr Endocrinol Metab 14 (2001): 1161-2

4. Bernecker C "Potassium iodide in bronchial asthma." Br Med J 4 (1969): 236

5. Denham MJ, Himsworth RL "Hyperthyroidism induced by potassium iodide given in the course of 125I-fibrinogen test." Age Ageing 3 (1974): 221-5

6. Johnson TM, Rapini RP "The Wolff-Chaikoff effect: hypothyroidism due to potassium iodide." Arch Dermatol 124 (1988): 1184-5

7. Meck RA, Chen MS, Kenny PJ "Criteria for the administration of KI for thyroid blocking of radioiodine." Health Phys 48 (1985): 141-57

8. Yalow RS "Risks in mass distribution of potassium iodide." Bull N Y Acad Med 59 (1983): 1020-7

9. Vagenakis AG, Wang CA, Burger A, Maloof F, Braverman LE, Ingbar SH "Iodide-induced thyrotoxicosis in Boston." N Engl J Med 287 (1972): 523-7

10. Gomolin IH "Iodinated glycerol-induced hypothyroidism." Drug Intell Clin Pharm 21 (1987): 726-7

11. Murray IP, Stewart RD "Iodide goitre." Lancet 1 (1967): 922-5

12. Hasen J "Serum triiodothyronine and thyroid-stimulating hormone levels in a patient with iodide-induced goiter." Isr J Med Sci 10 (1974): 782-5

13. Barnes ND, O'Connell EJ, Cloutier MD "Iodide-induced (SSKI) hypothyroidism in infancy." Ann Allergy 35 (1975): 305-8

14. Ayromlooi J "Congenital goiter due to maternal ingestion of iodides." Obstet Gynecol 39 (1972): 818-22

15. Khan F, Einbinder JM, Seriff NS "Suppurative ulcerating iododerma-a rare manifestation of inorganic iodide hypersensitivity." N Engl J Med 289 (1973): 1018-20

16. Rosenstein BJ, Plotnick LP, Blasco PA "Iodide-induced hypothyroidism without a goiter in an infant with cystic fibrosis." J Pediatr 93 (1978): 261-2

17. Waterfall WK "Iodide." Br Med J 281 (1980): 988-9

18. Livadas DP, Koutras DA, Souvatzoglou A, Beckers C "The toxic effect of small iodine supplements in patients with autonomous thyroid nodules." Clin Endocrinol (Oxf) 7 (1977): 121-7

19. Wood LC, Maloof F "Thyroid failure after potassium iodide treatment of diffuse toxic goiter." Trans Assoc Am Physicians 88 (1975): 235-47

20. Clark OH, Cavalieri RR, Moser C, Ingbar SH "Iodide-induced hypothyroidism in patients after thyroid resection." Eur J Clin Invest 20 (1990): 573-80

21. Dyck RF, Bear RA, Goldstein MB, Halperin ML "Iodine/iodide toxic reaction: case report with emphasis on the nature of the metabolic acidosis." Can Med Assoc J 120 (1979): 704-6

22. Horn B, Kabins SA "Iodide fever." Am J Med Sci 264 (1972): 467-71

23. Baumgartner TG "Potassium iodide and iododerma." Am J Hosp Pharm 33 (1976): 601-3

24. Wilkin JK, Strobel D "Iododerma occurring during thyroid protection treatment." Cutis 36 (1985): 335-7

25. Zone JJ "Potassium iodide and vasculitis." Arch Dermatol 117 (1981): 758-9

26. Huang TY, Peterson GH "Pulmonary edema and iododerma induced by potassium iodide in the treatment of asthma." Ann Allergy 46 (1981): 264-6

27. Bianco RP, Smith PJ, Keen RR, Jordan JE "Iodide intoxication. Report of a case." Oral Surg Oral Med Oral Pathol 32 (1971): 876-80

28. Stone OJ "Proliferative iododerma. A possible mechanism." Int J Dermatol 24 (1985): 565-6

29. Shelley WB "Generalized pustular psoriasis induced by potassium iodide. A postulated role for dihydrofolic reductase." JAMA 201 (1967): 1009-14

30. Soria C, Allegue F, Espana A, Rocamora A, Harto A, Ledo A "Vegetating iododerma with underlying systemic diseases: report of three cases." J Am Acad Dermatol 22 (1990): 418-22

31. Mackowiak PA "Drug fever: mechanisms, maxims and misconceptions." Am J Med Sci 294 (1987): 275-86

32. Curd JG, Milgrom H, Stevenson DD, Mathison DA, Vaughan JH "Potassium iodide sensitivity in four patients with hypocomplementemic vasculitis." Ann Intern Med 91 (1979): 853-7

33. Fischman RA, Fairclough GF, Cheigh JS "Iodide and negative anion gap." N Engl J Med 298 (1978): 1035-6

34. Kurtz SC, Aber RC "Potassium iodide as a cause of prolonged fever." Arch Intern Med 142 (1982): 1543-4

35. Eeckhout E, Willemsen M, Deconinck A, Somers G "Granulomatous vasculitis as a complication of potassium iodide treatment for Sweet's syndrome." Acta Derm Venereol 67 (1987): 362-4

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

More about Iosat (potassium iodide)

Consumer resources

Other brands: SSKI, Pima, ThyroShield

Professional resources

Related treatment guides