Gastrointestinal upset, diarrhea, burning of throat, metallic taste in mouth, and rarely inflammation of the salivary glands. These effects become more common as duration of therapy and dose increase.
Allergic reactions ranging from skin rashes to respiratory distress may occur, although life-threatening reactions are very uncommon.
Iodine-induced thyrotoxicosis, hypothyroidism, and goiter may occur, but incidence is less than 2%, even if therapy is used for longer durations.
A bluish skin discoloration involving sweat glands may occur after large doses of iodine-containing products.
Use in pregnancy. FDA Category D (See Phenytoin and Fosphenytoin). KI crosses the placental barrier and may cause hypothyroidism and goiter in the fetus. Risk is minimal with short-term use (˜10 days) and when given long before term.
Use in neonates. Because of the increased risk for hypothyroidism in neonates (<1 month old), thyroid function tests should be monitored.
Use in breastfeeding. KI passes into breast milk, but because radioiodines also pass into breast milk, lactating mothers should be cautioned to not breastfeed infants unless no other alternative is available.