POTASSIUM IODIDE

The following Overview, *** IODIDES ***, is relevant for this HSDB record chemical.

o   This overview assumes that basic life support measures
       have been instituted.

0.2.1 SUMMARY OF EXPOSURE
   0.2.1.1 ACUTE EXPOSURE
     A)  USES: Iodides have been utilized to treat iodine
         disorders, hyperthyroidism, bacterial, fungal or
         protozoal infections, and also were traditionally as
         expectorants because of their stimulatory effects on
         bronchial secretions. Potassium iodide is indicated for
         use as a thyroid blocking agent following exposure to
         radioisotopes of iodine from a nuclear reactor
         accident.
     B)  PHARMACOLOGY: Iodides are used by the thyroid gland in
         hormone production. Potassium iodide is taken up by the
         thyroid gland preventing absorption of radioactive
         iodide in cases where people are exposed in nuclear
         emergencies.
     C)  EPIDEMIOLOGY: Overdose is rare.
     D)  WITH THERAPEUTIC USE
      1)  ADVERSE EFFECTS: COMMON: POTASSIUM IODIDE can cause
          stomach upset, diarrhea, nausea, vomiting, stomach
          pain, skin rash and salivary gland swelling or
          tenderness. LESS COMMON: POTASSIUM IODIDE can cause
          gastrointestinal bleeding, confusion, dysrhythmias,
          numbness, pain or weakness in hands or feet, unusual
          fatigue, weakness or heaviness of legs, fever, and
          edema of neck or throat. Thyroid adenoma, goiter, and
          myxedema are also possible side effects. RARE: Iodism
          is a rare occurrence with iodides; however, it may
          develop during prolonged treatment or with the use of
          high doses. Symptoms include burning of mouth, severe
          headache, metallic taste, soreness of teeth and gums,
          symptoms of head cold, irritation of the eyes with
          swelling of the eyelids, unusual increase in
          salivation, acneform skin lesions in the seborrheic
          areas, and rarely, severe skin eruptions.
     E)  WITH POISONING/EXPOSURE
      1)  TOXICITY: Overdose of potassium iodide results in
          angioedema, laryngeal edema, and cutaneous hemorrhage.
          Very large doses could theoretically cause
          hyperkalemia and resulting dysrhythmias, but this has
          not been reported to date.
  0.2.3 VITAL SIGNS
  0.2.5 CARDIOVASCULAR
   0.2.5.1 ACUTE EXPOSURE
     A)  WITH THERAPEUTIC USE
      1)  Periarteritis nodosa and dysrhythmias may occur with
          iodides.
  0.2.8 GASTROINTESTINAL
   0.2.8.1 ACUTE EXPOSURE
     A)  WITH THERAPEUTIC USE
      1)  Nausea, vomiting, abdominal pain and parotitis have
          been reported with potassium iodide use.
  0.2.14 DERMATOLOGIC
   0.2.14.1 ACUTE EXPOSURE
     A)  WITH THERAPEUTIC USE
      1)  Chronic oral administration can produce various
          cutaneous manifestations, including rash, erythema
          nodosum, polymorphic eruptions, urticaria, vasculitis,
          and petechia.
  0.2.16 ENDOCRINE
   0.2.16.1 ACUTE EXPOSURE
     A)  WITH THERAPEUTIC USE
      1)  Chronic iodide therapy has produced goiters,
          hypothyroidism, and rarely hyperthyroidism.
  0.2.19 IMMUNOLOGIC
   0.2.19.1 ACUTE EXPOSURE
     A)  WITH THERAPEUTIC USE
      1)  Acute hypersensitivity reactions including angioedema,
          Stevens Johnson syndrome, systemic vasculitis, and
          serum-sickness-like reactions may occur.
  0.2.20 REPRODUCTIVE HAZARDS
    A)  Potassium iodide is classified as FDA pregnancy category
        D. RADIATION EMERGENCY: In 2001, the FDA issued a
        guideline for the use of potassium iodide in the event
        of a nuclear disaster with radioactive iodide. The
        recommendation from the FDA states pregnant women should
        be given KI for their own protection and that of the
        fetus since iodine (radioactive or not) readily crosses
        the placenta. Excess doses of stable iodide will have an
        effect on the fetus, therefore, repeat doses are not
        recommended. Sodium Iodide I-131 is classified as FDA
        pregnancy category X and sodium iodide I-123 is
        classified as pregnancy category C. Cretinism and goiter
        have been reported in children born to mothers
        chronically taking iodides during pregnancy.
  0.2.21 CARCINOGENICITY
   0.2.21.2 HUMAN OVERVIEW
     A)  At the time of this review, the manufacturers do not
         report any carcinogenic potential of potassium iodide.
         Long term studies to evaluate the carcinogenic
         potential of iodides have not been preformed.
   0.2.21.3 ANIMAL OVERVIEW
     A)  At the time of this review, the manufacturers do not
         report any carcinogenic potential of potassium iodide.
         Long term studies to evaluate the carcinogenic
         potential of iodides have not been preformed.
  0.2.22 GENOTOXICITY
    A)  At the time of this review, the manufacturer does not
        report any mutagenic potential of potassium iodide(Prod
        Info IOSAT(TM) oral tablets, 2005; Prod Info
        THYROSHIELD(TM) oral solution, 2005; Prod Info SSKI(R)
        oral solution, 1999). Long term studies to evaluate the
        mutagenic potential of iodides have not been preformed.

A)  Plasma iodide levels are not clinically useful or readily
       available.
   B)  Monitor thyroid function in cases of severe overdose for
       decreased serum T4 levels and increased serum TSH levels.
   C)  Monitor ECG for signs of potassium toxicity in cases of
       severe overdose with potassium iodide.
   D)  Monitor serum electrolytes and renal function in patients
       with severe overdose.

0.4.2 ORAL EXPOSURE
    A)  MANAGEMENT OF MILD TO MODERATE TOXICITY
     1)  Treatment is symptomatic and supportive.
    B)  MANAGEMENT OF SEVERE TOXICITY
     1)  Treat acute allergic reactions with or without
         laryngeal edema with epinephrine and antihistamines.
         Treat serum-sickness-like reactions with antihistamines
         and corticosteroids. Treat cases of iodism with
         intravenous sodium chloride. Most symptomatic cases of
         thyrotoxicosis can be treated with beta-blockers;
         treatment with propylthiouracil I131 or surgery is
         rarely necessary. Overdose with potassium iodide can
         cause dysrhythmias due to potasium toxicity. Treat as
         necessary in overdose cases where potassium iodide is
         the suspected agent.
    C)  DECONTAMINATION
     1)  PREHOSPITAL: Consider using activated charcoal if
         ingestion was recent, a substantial ingestion, and the
         patient can protect their airway.
     2)  HOSPITAL: Consider using activated charcoal if
         ingestion was recent, a substantial ingestion, and the
         patient can protect their airway.
    D)  AIRWAY MANAGEMENT
     1)  Ensure adequate ventilation and perform endotracheal
         intubation early in rare patients with serious
         toxicity.
    E)  ANTIDOTE
     1)  There is no antidote for iodide poisoning.
    F)  HYPERSENSITIVITY REACTION
     1)  MILD/MODERATE: Antihistamines, inhaled beta agonists,
         corticosteroids. SEVERE: Oxygen, aggressive airway
         management, antihistamines, epinephrine (ADULT: 0.3 to
         0.5 mL of a 1:1000 solution intramuscularly or
         subcutaneously; CHILD: 0.01 mL/kg, 0.5 ml max; may
         repeat in 20 to 30 min), corticosteroids, ECG
         monitoring, and IV fluids.
    G)  SERUM SICKNESS DUE TO DRUG
     1)  Treat serum-sickness-like reactions with
         antihistamines. Corticosteroids should be administered
         if antihistamines are not effective or if severe
         symptoms persist.
    H)  THYROTOXICOSIS
     1)  Discontinuing the inciting agent is usually the only
         therapy necessary in mild cases. Beta blockers may be
         used in symptomatic patients. RARELY propylthiouracil,
         I131, or surgery are necessary.
    I)  HYPOTHYROIDISM
     1)  Short-term administration of thyroid hormone
         supplements may hasten recovery. Discontinuation of the
         iodide source will usually result in restoration of
         normal thyroid function within several weeks.
    J)  ENHANCED ELIMINATION
     1)  A diuretic such as mannitol should be administered in
         treatment of chronic iodide poisoning to increase renal
         excretion of iodide. Fluids and sodium chloride intake
         will also hasten iodide excretion.
    K)  PATIENT DISPOSITION
     1)  OBSERVATION CRITERIA: All patients with overdose
         ingestions should be evaluated in a healthcare facility
         until symptoms are resolved.
     2)  ADMISSION CRITERIA: Patient demonstrating acute
         allergic reaction, thyrotoxicosis, or severe toxicity
         should be admitted to the hospital.
     3)  CONSULT CRITERIA: Consult a medical toxicologist or
         Poison Center for assistance in managing patients with
         severe toxicity or in whom the diagnosis is unclear.
    L)  PITFALLS
     1)  Ingestions involving potassium iodide can cause
         potassium toxicity.
    M)  PHARMACOKINETICS
     1)  Iodides are readily absorbed in the GI tract and
         distribute widely throughout extracellular fluid of the
         thyroid gland. The majority of excretion is through the
         kidneys.
    N)  DIFFERENTIAL DIAGNOSIS
     1)  Includes other agents that may cause similar effects,
         such as iodine, which is more toxic.

A)  TOXICITY: A specific toxic dose for iodides has not been
       established. Up to 10 grams of sodium iodide has been
       administered IV without toxicity. Doses up to 6 grams/day
       of potassium iodide have been used for dermatological
       fungal infections. Children received one half or one
       third of this dose. THERAPEUTIC DOSES: POTASSIUM IODIDE
       (RADIATION EMERGENCY) ADULTS: 130 mg once daily.
       CHILDREN: OVER 12 YEARS TO 18 YEARS, WEIGHING AT LEAST
       150 POUNDS: 130 mg once daily. OVER 12 YEARS TO 18 YEARS,
       WEIGHING LESS THAN 150 POUNDS: 65 mg once daily. OVER 3
       YEARS TO 12 YEARS: 65 mg once daily. OVER 1 MONTH TO 3
       YEARS: 32.5 mg once daily. AT BIRTH TO 1 MONTH : 16.25 mg
       once daily.