potassium iodide (Pima Syrup, SSKI, iosat, ThyroSafe, ThyroShield)
Classes: Expectorants; Antidotes, Other; Antithyroid Agents
Dosing and uses of Pima Syrup, SSKI (potassium iodide)
Adult dosage forms and strengths
tablet
- 65mg
- 130mg
oral solution
- 65mg/mL
- 325mg/5mL
oral solution (concentrated)
- 1g/mL
Radiation Emergency
Indicted during environmental radiation emergency to block uptake of radioactive iodine isotopes in thyroid and reduce risk of thyroid cancer
130 mg PO qDay; not to exceed 1 dose/24 hr
Ideally initiate 1-48 hr prior to exposure
Continue daily dose until exposure risk has passed and/or until other measures (eg, evacuation, sheltering, control of the food and milk supply) have been successfully implemented
Risk reduction with acute exposure
- KI initiated shortly before or immediately after acute exposure: 90-99% risk reduction
- KI initiated within 3-4 hr after acute exposure: 50% risk reduction
- KI initiated up to 12 hr after acute exposure: limited benefit may be achieved
Expectorant
SSKI: 300-600 mg PO q6-8hr
Thyrotoxic Crisis
250-500 mg (5-10 gtt of 1 g/mL) PO q4-6hr
Preoperative Thyroidectomy
50-250 mg (1-5 gtt of 1 g/mL) PO q8hr for 10-14 days
Other Indications & Uses
Cystic fibrosis, chronic sinusitis (adjunct)
Pediatric dosage forms and strengths
tablet
- 65mg
- 130mg
oral solution
- 65mg/mL
- 325mg/5mL
oral solution
- 1g/mL
Radiation Emergency
Indicted during environmental radiation emergency to block uptake of radioactive iodine isotopes in thyroid and reduce risk of thyroid cancer
Infants <1 month: 16.25 mg PO qDay; not to exceed 1 dose/24 hr
1 month-3 years: 32.5 mg PO qDay; not to exceed 1 dose/24 hr
3-13 years: 65 mg PO qDay; not to exceed 1 dose/24 hr
>13 years or adolescents weighing >70 kg (154 lb): 130 mg PO qDay; not to exceed 1 dose/24 hr
Ideally initiate 1-48 hr prior to exposure
Continue daily dose until exposure risk has passed and/or until other measures (eg, evacuation, sheltering, control of the food and milk supply) have been successfully implemented
Risk reduction with acute exposure
- KI initiated shortly before or immediately after acute exposure: 90-99% risk reduction
- KI initiated within 3-4 hr after acute exposure: 50% risk reduction
- KI initiated up to 12 hr after acute exposure: limited benefit may be achieved
Neonatal Graves Disease
SSKI: 1 gtt PO q8hr
Expectorant
SSKI: 60-250 mg PO q6hr
Pima Syrup, SSKI (potassium iodide) adverse (side) effects
Frequency not defined
Arrhythmia
Skin rash
Gastrointestinal irritation or bleeding
Diarrhea
Paresthesia
Swelling or neck or throat
Goiter
Hypothyroidism
Hyperthyroidism
Myxedema
Thyroid adenoma
Allergic reactions (fever, rash)
Lymph node swelling
Salivary gland swelling/tenderness
Warnings
Contraindications
Iodine sensitivity (although allergy to radiocontrast media, contact dermatitis from iodine-containing antibacterials, allergy to seafood should NOT be considered evidence of potassium iodide allergy)
Hyperthyroidism
Respiratory failure
Cautions
Avoid repeat dosing in neonates or women who are pregnant or breastfeeding if possible; in acute radiation exposure, prioritize these individuals for evacuation; although these precautions should be taken, the benefits of short-term use of KI to block uptake of radioactive iodine by the thyroid gland far exceed its chances of side effects
Prescribe for radiation exposure only upon order from authorities
Caution in tuberculosis
Iodine poisoining (Iodism): Metallic taste, sore mouth, severe headache
Pregnancy and lactation
Pregnancy category: d
Increased risk of thyroid suppression in the fetus and neonate leads to a specific recommendation that newborns and pregnant women be given priority with regard to evacuation, safe shelter, and safe food/milk during radiation emergency in order to obviate, as possible, the need for repeat dosing with KI
Lactation: Excreted in breast milk
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Pima Syrup, SSKI (potassium iodide)
Mechanism of action
Expectorant: Iodine helps to increase respiratory secretions and decrease viscosity
Hyperthyroidism: Suppresses thyroid hormone synthesis
Thyroid protective: Systemically circulating potassium iodide is readily taken up by thyroid gland by sodium/iodide transporter in basal membrane; concentration gradient of thyroid gland to plasma is 20-50:1
Pharmacokinetics
Distribution: Significant extracellular distribution, with most accumulation in thyroid gland
Onset: Therapeutic effects in hyperthyroidism observed within 24 hr
Maximum effect: After 10-15 days of therapy
Duration of effect: Therapeutic effect may persist up to 6 weeks after chronic administration; 24 hr for radioactive iodine exposure
Metabolism: Unknown
Excretion: RenaL