"Iodine supplementation causes bromine to be released from within the tissues of the body, into the bloodstream, and if this happens rapidly and in sufficient quantities, produces toxic symptoms. This is treated with salt (the chloride ion flushes the bromine into the urine) and may necessitate the reduction of the Iodine dosage. Potassium chloride can be used in place of ordinary salt (table salt, for example) in people who are salt-sensitive."
It is not kidney irritation that causes the symptoms, but the bromine toxicity.
"I am recognizing bromine toxicity symptoms much more commonly than I had, even several months ago, and now consider that this may be an extremely common toxicity. "