MECHANISM OF ACTION
Topiramate is a weak carbonic anhydrase inhibitor.
Carbonic anhydrase inhibitors reduce urinary citrate excretion and increase
urinary pH. Concurrent use of topiramate with other carbonic anhydrase
inhibitors may increase the risk of kidney stone formation.(1)
DISCUSSION
Topiramate is a weak carbonic anhydrase inhibitor. Carbonic
anhydrase inhibitors reduce urinary citrate excretion and increase urinary
pH. Concurrent use of topiramate with other carbonic anhydrase inhibitors
may increase the risk of kidney stone formation and should therefore be
avoided.(1)
CLINICAL EFFECTS
The concurrent use of topiramate with another carbonic
anhydrase inhibitor may increase the risk of kidney stone formation.(1)
SEVERITY LEVEL
2-Severe Interaction: Action is required to reduce the risk
of severe adverse interaction.
PATIENT MANAGEMENT
The US manufacturer of topiramate states that the
concurrent use of topiramate with other carbonic anhydrase inhibitors should
be avoided. Patients receiving concurrent therapy should be monitored for
the appearance of or worsening of metabolic acidosis.(1)
PREDISPOSING FACTORS
The risk of kidney stone formation may be increased
in patients on a ketogenic diet or with poor hydration.(1)
REFERENCE