Potassium Iodide

Potassium iodide is an iodide salt with nutritional, thyroid-related and selected antimicrobial applications. Veterinary use includes historical or adjunctive treatment of sporotrichosis and some granulomatous infections, particularly in large animals. It also has an empirical expectorant history. The antimicrobial mechanism and condition-specific clinical benefit are incompletely characterized.

Group

Iodide supplement and adjunct antifungal

Mechanism of Action

Potassium iodide dissociates to release iodide, which is taken up by the thyroid and contributes to thyroid-hormone synthesis. A large stable-iodide supply can temporarily reduce thyroid uptake of radioactive iodine. Proposed antimicrobial effects involve direct and host-mediated actions, but the mechanism against granulomatous infections is uncertain. Increased respiratory secretion has been proposed for its empirical expectorant role.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Fungal infection adjunct — Initial	5 mg/kg	PO	Every 8 h	Increase gradually according to response and tolerance.
Fungal infection adjunct — Maintenance	25 mg/kg	PO	Every 8 h	Upper reported titration endpoint.
Radiation-related thyroid protection	2 mg/kg	PO	Every 24 h	Up to 14 days; Reported course 10-14 days or until exposure risk passes.
Expectorant	5 mg/kg	PO	Every 8 h
Sporotrichosis	40 mg/kg	PO	Every 8 h	Saturated potassium iodide; at least 60 days.
Sporotrichosis	40 mg/kg	PO	Every 12 h	Give with food; itraconazole may cause fewer adverse effects.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Fungal infection adjunct — Initial	5 mg/kg	PO	Every 8 h	Increase gradually according to response and tolerance.
Fungal infection adjunct — Maintenance	25 mg/kg	PO	Every 8 h	Upper reported titration endpoint.
Radiation-related thyroid protection	2 mg/kg	PO	Every 24 h	Up to 14 days; Reported course 10-14 days or until exposure risk passes.
Expectorant	5 mg/kg	PO	Every 8 h
Sporotrichosis	20 mg/kg	PO	Every 12–24 h	At least 60 days; monitor iodism closely.

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Reported iodide therapy	10–15 g/animal	PO	Every 24 h	Up to 60 days; Adult cattle; course 30-60 days.
Reported iodide therapy	5–10 g/animal	PO	Every 24 h	Up to 60 days; Calves; course 30-60 days.

Horses

Use / stage	Dose	Route	Schedule	Instructions
Reported iodide therapy	10–15 g/animal	PO	Every 24 h	Up to 60 days; Adult horses; course 30-60 days.
Reported iodide therapy	5–10 g/animal	PO	Every 24 h	Up to 60 days; Ponies; course 30-60 days.

Indications

Treatment or adjunctive treatment of selected sporotrichosis in veterinary patients, including supported equine or small-animal cases.
Historical adjunctive treatment of selected granulomatous fungal or fungus-like infections, including some conidiobolomycosis cases, with limited disease-specific evidence.
Iodide supplementation in selected patients with iodine deficiency.
Specialist thyroid blockade against radioactive iodine uptake in selected radiological exposure situations, largely extrapolated from nonveterinary evidence.
Historical expectorant use for retained respiratory secretions, with unestablished clinical efficacy.

Contraindications

Pregnancy and foals
Do not administer intravenously.

Adverse effects

Iodism, salivation, nausea, coat changes, eyelid swelling and cough; feline cardiomyopathy reported.

Toxicity

Iodism can cause tearing, nasal discharge, GI signs, coat scaling, fever, weakness and cardiomyopathy; withdrawal and supportive management depend on severity.

Preparations

Preparation	Form	Strength	Route
Potassium Iodide 65 mg	Tablet	65 mg / tablet	PO
Potassium Iodide 130 mg	Tablet	130 mg / tablet	PO
Potassium iodide solution 65 mg/mL	Oral Liquid	65 mg / mL	PO
Saturated potassium iodide 1 g/mL	Oral Liquid	1 g / mL	PO

Monitoring and Administration

Monitor clinical response and signs of iodism; antifungal and expectorant efficacy are not well established.

Protect from moisture, heat and light; do not freeze. A tablet-derived solution in water plus milk/juice/syrup is described as stable for 7 days refrigerated.

Horses: 10-40 mg/kg/day is reported, but the route is not stated for this specific regimen; do not infer an administration route.