Version July 2025
Dosage guidance:
Safety: Errors have occurred during the prescribing, dispensing, and administration of iodine-containing solutions; verify the dosing units (eg, drops, mL) and intended solution concentration before administration (Ref). Doses may be presented as drops or mL; use caution and carefully verify dosage units before dispensing or administering.
Dosage form information: Lugol's 5% solution (potassium iodide 10% and iodine 5%) contains ~6.25 mg iodine per drop; 1 drop = 0.05 mL (Ref).
Graves disease/neonatal hyperthyroidism: Limited data available: Lugol's 5% solution: Oral: 1 drop (0.05 mL) 3 times daily in combination with antithyroid agent and beta-blocker; if adequate response is not achieved within 24 to 36 hours, may increase dose by 50%; duration is usually limited to 10 to 14 days (Ref).
Dosage guidance:
Safety: Errors have occurred during the prescribing, dispensing, and administration of iodine-containing solutions; verify the dosing units (eg, drops, mL) and intended solution concentration before administration (Ref). Doses may be presented as drops or mL; use caution and carefully verify dosage units before dispensing or administering.
Dosage form information: Lugol's 5% solution (potassium iodide 10% and iodine 5%) contains ~6.25 mg iodine per drop; 1 drop = 0.05 mL (Ref).
Thyrotoxic crisis/thyroid storm: Limited data available: Children and Adolescents: Lugol's 5% solution: Oral: 4 to 10 drops (0.2 to 0.5 mL) 3 times daily; begin therapy preferably 1 hour following the initial dose of either propylthiouracil or methimazole (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in the manufacturer’s labeling.
There are no dosage adjustments provided in the manufacturer’s labeling.
(For additional information see "Potassium iodide and iodine (Lugol solution): Drug information")
Note: Lugol's 5% solution (potassium iodide 10% and iodine 5%) contains ~6.25 mg iodine/iodide per drop; 1 drop = 0.05 mL (Ref). Errors have occurred involving iodine-containing solutions; verify the indication and intended solution concentration before administration (Ref).
Antiseptic: Topical: Apply directly to area(s) requiring antiseptic.
Graves disease, thyroidectomy preparation:
Note: Use is not recommended in patients with thyrotoxicosis caused by a toxic adenoma or toxic multinodular goiter due to the risk of exacerbating hyperthyroidism (Ref).
Oral: Lugol's 5% solution: 5 to 7 drops (0.25 to 0.35 mL) 3 times daily for 10 days before surgery (Ref).
Note: Antithyroid drug therapy (eg, methimazole) is started several weeks before surgery to achieve euthyroidism; if not euthyroid prior to surgery, or if urgent surgery is required, consider concurrent beta-blockade (eg, propranolol) in the immediate preoperative period to reduce the risk of thyroid storm (Ref).
Thyroid gland protection during radiopharmaceutical use (off-label use): Note: Regimens/protocols vary by radiopharmaceutical. Generally, ~100 mg/day of iodine/iodide is required for thyroid block (Ref). Initiate 1 to 48 hours prior to radiopharmaceutical exposure and continue after radiopharmaceutical administration until risk of exposure has diminished (treatment initiation time and duration are dependent on the radiopharmaceutical agent used, consult specific protocol or labeling). The following product-specific recommendations are provided in the radiopharmaceutical manufacturer's labeling:
Iodine I-123 radiopharmaceuticals: Oral: Lugol’s 5% solution: 16 drops/day (0.8 mL/day) to achieve a dose of 100 mg/day of iodine/iodide (radiopharmaceutical manufacturer's labeling [Adreview, Datscan]).
Iodine I-125 and I-131 radiopharmaceuticals: Oral: Lugol’s 5% solution: 10 drops (0.5 mL) 3 times daily (radiopharmaceutical manufacturer's labeling [Jeanatope, Megatope, Volumex]).
Thyroid storm: Note: Administer at least 1 hour after antithyroid drug administration (eg, propylthiouracil, methimazole) (Ref).
Oral: Lugol's 5% solution: 4 to 10 drops (0.2 to 0.5 mL) every 6 to 8 hours (Ref). May discontinue after evidence of clinical improvement (eg, defervescence, resolution of CNS and cardiovascular manifestations); for patients undergoing thyroidectomy within 10 to 14 days of initiating iodine therapy, may continue until day of surgery (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in the manufacturer's labeling.
There are no dosage adjustments provided in the manufacturer's labeling.
The following adverse drug reactions are derived from product labeling unless otherwise specified. Also see individual agents.
Postmarketing:
Endocrine & metabolic: Thyroiditis (Yang 2017)
Gastrointestinal: Gastrointestinal hemorrhage (duodenal) (Kinoshita 2010)
Hypersensitivity to iodine or any component of the formulation; tuberculosis (TB) disease (active TB); dermatitis herpetiformis; hypocomplementemic vasculitis; nodular thyroid disease with heart disease
Concerns related to adverse effects:
• Hypothyroidism: Prolonged use can lead to hypothyroidism.
• Skin reactions: Can cause acne flare-ups and/or dermatitis.
Disease-related concerns:
• Adrenal insufficiency: Use with caution in patients with Addison disease.
• Bronchitis: Use with caution in patients with acute bronchitis.
• Cardiac disease: Use with caution in patients with cardiac disease.
• Myotonia congenita: Use with caution in patients with myotonia congenita.
• Renal impairment: Use with caution in patients with renal impairment.
• Thyroid disease: Use with caution in patients with a history of hyperthyroidism.
• Tuberculosis: Use with caution in patients with tuberculosis.
Lugol's 5% oral solution (potassium iodide 10% and iodine 5%) contains potassium iodide 100 mg/mL and iodine 50 mg/mL and provides 6.25 mg iodide/iodine per drop.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, External:
Lugols Strong Iodine: Potassium iodide 10% and iodine 5% (8 mL)
Generic: Potassium iodide 10% and iodine 5% (8 mL)
Solution, Oral:
Generic: Potassium iodide 10% and iodine 5% (14 mL, 473 mL)
Tincture, External:
Generic: Potassium iodide 5% and iodine 7% (30 mL, 480 mL)
Yes
Oral: Dilute with water or fruit juice.
Topical: Apply topically directly to area(s) requiring antiseptic.
Oral: Dilute with water or juice. In patients with thyroid storm, administer at least 1 hour after antithyroid drug administration (eg, propylthiouracil, methimazole).
Store at room temperature of 15°C to 30°C (59°F to 86°F). Protect from light and keep container tightly closed.
Oral solution: Treatment of hyperthyroidism in the immediate preoperative period in patients undergoing thyroidectomy and management of thyrotoxic crisis (FDA approved in adults).
Topical solution: Provide topical antisepsis (FDA approved in adults).
Potassium iodide and iodine (Strong Iodide Solution or Lugol's solution) may be confused with potassium iodide products, including saturated solution of potassium iodide (SSKI)
Dosage volume: Dosing errors have been reported during the prescribing, dispensing, and administration of potassium iodide-containing solutions (eg, Lugol's, SSKI). Errors have occurred when mL doses were administered, when only drops were indicated for the dose. Carefully review dosage and administration information; appropriate oral dosage is most commonly expressed as drops to provide doses less than 1 mL. Dispensing unit doses is also highly recommended; pharmacists should never dispense quantities that could be lethal if consumed as a single dose (ISMP 2011).
Refer to individual components.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program
Aliskiren: Potassium Salts may increase hyperkalemic effects of Aliskiren. Risk C: Monitor
AMILoride: Potassium Salts may increase hyperkalemic effects of AMILoride. Management: Amiloride and potassium supplements should not be used except in severe or refractory cases of hypokalemia. If coadministered, monitor serum potassium closely as rapid increases in potassium are possible. Risk D: Consider Therapy Modification
Angiotensin II Receptor Blockers: Potassium Salts may increase hyperkalemic effects of Angiotensin II Receptor Blockers. Risk C: Monitor
Angiotensin-Converting Enzyme Inhibitors: Potassium Salts may increase hyperkalemic effects of Angiotensin-Converting Enzyme Inhibitors. Risk C: Monitor
Cardiac Glycosides: Antithyroid Agents may increase serum concentration of Cardiac Glycosides. Risk C: Monitor
CycloSPORINE (Systemic): May increase hyperkalemic effects of Potassium Salts. Risk C: Monitor
Digitoxin: Potassium Salts may increase adverse/toxic effects of Digitoxin. Potassium Salts may decrease therapeutic effects of Digitoxin. Risk C: Monitor
Drospirenone-Containing Products: May increase hyperkalemic effects of Potassium Salts. Risk C: Monitor
Eplerenone: May increase hyperkalemic effects of Potassium Salts. Management: This combination is contraindicated in patients receiving eplerenone for treatment of hypertension. Potassium supplements may be needed to treat/prevent hypokalemia in select patients with heart failure receiving eplerenone and high dose loop diuretics. Risk D: Consider Therapy Modification
Finerenone: Potassium Salts may increase hyperkalemic effects of Finerenone. Risk C: Monitor
Heparin: May increase hyperkalemic effects of Potassium Salts. Risk C: Monitor
Heparins (Low Molecular Weight): May increase hyperkalemic effects of Potassium Salts. Risk C: Monitor
Lithium: Potassium Iodide may increase hypothyroid effects of Lithium. Risk C: Monitor
MetyraPONE: Coadministration of Antithyroid Agents and MetyraPONE may alter diagnostic results. Management: Consider alternatives to the use of the metyrapone test in patients taking antithyroid agents. Risk D: Consider Therapy Modification
Nicorandil: May increase hyperkalemic effects of Potassium Salts. Risk C: Monitor
Nonsteroidal Anti-Inflammatory Agents: May increase hyperkalemic effects of Potassium Salts. Risk C: Monitor
Sodium Iodide I131: Iodine may decrease therapeutic effects of Sodium Iodide I131. Management: Discontinue topical iodine at least 3 weeks before sodium iodide I-131 administration, and avoid concurrent use. Risk X: Avoid
Sodium Iodide I131: Potassium Iodide may decrease therapeutic effects of Sodium Iodide I131. Management: Discontinue potassium iodide at least 3 weeks before sodium iodide I-131 administration, and avoid concurrent use. Risk X: Avoid
Sodium Perchlorate: Iodine may decrease therapeutic effects of Sodium Perchlorate. Risk C: Monitor
Spironolactone: Potassium Salts may increase hyperkalemic effects of Spironolactone. Risk X: Avoid
Theophylline Derivatives: Antithyroid Agents may increase serum concentration of Theophylline Derivatives. Risk C: Monitor
Triamterene: Potassium Salts may increase hyperkalemic effects of Triamterene. Risk X: Avoid
Vitamin K Antagonists: Antithyroid Agents may decrease anticoagulant effects of Vitamin K Antagonists. Risk C: Monitor
Potassium iodide/iodine may be used in the management of thyroid storm or thyrotoxic heart failure in pregnant patients (ACOG 2020). Potassium iodide solution may be preferred for use in pregnant patients with hyperthyroidism who do not tolerate antithyroid medications in preparation for surgery (ATA [Alexander 2017]).
Refer to the Sodium Iodide monograph for additional information related to systemic iodine and pregnancy.
Refer to the Iodine monograph for additional information related to topical iodine exposure and pregnancy.
Thyroid function tests, signs/symptoms of hyperthyroidism
In hyperthyroidism, iodine temporarily inhibits thyroid hormone synthesis and secretion into the circulation; use also decreases thyroid gland size and vascularity. Serum T4 and T3 concentrations can be reduced for several weeks with use but effect will not be maintained.
Following radioactive iodine exposure, potassium iodide blocks uptake of radioiodine by the thyroid, reducing the risk of thyroid cancer.
Onset of action: Hyperthyroidism: 24 to 48 hours
Peak effect: 10 to 15 days after continuous therapy
