Salivary glands affected: While all salivary glands are affected, the higher the serous component the greater the toxicity. The parotid glands tend to show greater toxicity than the submandibular or sublingual glands.
Short term effect:
(1) swelling of one or more parotid glands due to the iodide ("iodide mumps", see below under contrast media-related toxicity).
(2) acute radiation sialadenitis
Long term effects:
(1) chronic sialadenitis with intermittent swelling and pain
(2) xerostomia
(3) change in taste
Administration of agents to increase salivary flow during I-131 therapy can reduce the duration of salivary gland exposure and toxicity, These include:
(1) pilocarpine (acts as a sialagogue, or stimulator of saliva flow)
(2) sour candy (lemon drops)
Risk factors for increased toxicity:
(1) higher dose of I-131
(2) dehydration
(3) agents that slow production of saliva
(4) obstruction to saliva flow (strictures of ducts, lithiasis)
(5) renal failure (reduced excretion results in increased plasma iodide levels)
