Topamax Warnings & Precautions

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Topamax - Warnings & Precautions [Topiramate]

Cases of moderately severe metabolic acidosis have been reported in patients as young as 5 months old, especially at daily doses above 5 mg/ kg/ day. Although not approved for the prophylaxis of migraine, the incidence of persistent treatment-emergent decreases in serum bicarbonate in placebo-controlled trials for adults for prophylaxis of migraine was 44% for 200 mg/ day, 39% for 100 mg/ day, 23% for 50 mg/ day, and 7% for placebo. The incidence of a markedly abnormally low serum bicarbonate (i. e., absolute value <17 mEq/ L and >5 mEq/ L decrease from pre-treatment) in these trials was 11% for 200 mg/ day, 9% for 100 mg/ day, 2% for 50 mg/ day, and <1% for placebo.

Some manifestations of acute or chronic metabolic acidosis may include hyperventilation, nonspecific symptoms such as fatigue and anorexia, or more severe sequelae including cardiac arrhythmias or stupor. Chronic, untreated metabolic acidosis may increase the risk for neprolithiasis or nephrocalcinosis, and may also result in osteomalacia (referred to as rickets in pediatric patients) and/ or osteoporosis with an increased risk for fractures. Chronic metabolic acidosis in pediatric patients may also reduce growth rates. A reduction in growth rate may eventually decrease the maximal height achieved.

The effect of topiramate on growth and bone-related sequelae has not been systematically investigated. Measurement of baseline and periodic serum bicarbonate during topiramate treatment is recommended. If metabolic acidosis develops and persists, consideration should be given to reducing the dose or discontinuing topiramate (using dose tapering). If the decision is made to con-tinue patients on topiramate in the face of persistent acidosis, alkali treatment should be considered. Acute Myopia and Secondary Angle Closure Glaucoma A syndrome consisting of acute myopia associated with secondary angle closure glaucoma has been reported in patients receiving TOPAMAX Ž .