The risk and management of kidney stones from the use of topiramate and zonisamide in migraine and idiopathic intracranial hypertension

CASE HISTORY A 40-year-old woman has a 15-year history of migraine without aura that has been chronic for 5 years. While on TPM 100 mg daily for 2 years without side effects, her migraine frequency has decreased from 20 days per month to 6 days per month. She then developed a first-time kidney stone that passed spontaneously. Upon analysis, the stone was determined to be calcium phosphate. QUESTIONS What is the type of kidney stones that form and their pathophysiology? What is the frequency of kidney stones in migraineurs on TPM and ZNS and the general population? Is the risk dose and time dependent? Is a prior history of kidney stones a contraindication to use of either medication? Is formation of kidney stones a contraindication to ongoing use of TPM or ZNS? If migraineurs who develop a kidney stone(s) on TPM continue the drug, is there any way to prevent further stone formation? In patients with IIH, is the risk of kidney stone formation a contraindication to combined use of TPM and acetazolamide (ATZ)?