Topomax, a medication frequently prescribed for migraine headaches as well as weight loss, may up the risk of kidney stones.
In a study published by the National Kidney Foundation, researchers found that the drug appeared to deplete citrate in the urine of patients, an ion that helps inhibit the calcium salt crystallization that can develop into some types of kidney stones.
The study included 12 patients who were prescribed Topomax by providers in a headache clinic. A 24-hour urine sample was collected before beginning the medication, and again 30 days and 60 days after starting the drug.
On average, the patients’ urinary citrate excretion decreased to 279 mg per day after being on Topomax for 30 days. Even more alarmingly, the citrate output continued to decrease as the study went on, and levels were even more dangerous for kidney stones at 60 days versus 30.
At 60 days, patients who remained in the study had an average citrate excretion of 196 mg per day. Lead researcher Allan Jhagroo, MD, said that any level less than 320 mg per day puts patients at risk for kidney stone development. He prefers to see patients above 500 mg per day.
While none of the 12 patients in the study developed kidney stones during the trial or at the 6 to 12 month follow-up, the risk was still dramatic in the sample.
Passing kidney stones can be very painful. While approximately 13% of the U.S. population has a chronic kidney disorder, some may not know it because it usually starts out asymptomatic. Kidney stones can be a sudden and excruciating experience.
Because the citrate depletion caused by the drug was rapid and progressive, the study authors recommended that this be considered before prescribing Topomax to patients, especially those with a history of kidney stones or with other risk factors.
The study was small, and the effects of Topomax and the clinical implications should be explored with more research.
To avoid the side effects of medication yet find relief of headache, many people turn to chiropractic care, which research has shown gives patients a 90% reduction in migraine frequency.
Jhagroo R, et al. Topiramate results in a rapid and progressive decline in urinary citrate over 60 days: A prospective study. National Kidney Foundation 2013: http://ww3.aievolution.com/nkf1301/index.cfm?do=abs.viewAbs&abs=1368.