Article Text

Unexpected outcome (positive or negative) including adverse drug reactions
Topiramate induced agranulocytosis
  1. Eiko Nakano Minakawa1,
  2. Riki Matsumoto2,
  3. Masako Kinoshita1
  1. 1
    Utano National Hospital, National Hospital Organization, Neurology, 8 Ondoyama-cho, Narutaki, Ukyoku, Kyoto, 616-8255, Japan
  2. 2
    Kyoto University Graduate School of Medicine, Neurology, Kawaharacho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
  1. Masako Kinoshita, deuxnocturnes{at}


A man in his 40s with a past history of neutropenia during zonisamide administration developed agranulocytosis 1 month after adding on topiramate to treat intractable partial epilepsy. His concurrent medication included phenytoin and acetazolamide. His white blood cell count recovered 5 days after discontinuation of topiramate. Topiramate is a sulfamate whose mechanism of antiepileptic activity is considered to include inhibition of carbonic anhydrase. Topiramate has a potential risk for haematopoietic adverse events; such events are rare and are related to immuno-allergic reaction or toxic effect of sulfonamides and sulfamates, including carbonic anhydrase inhibitors. Because this class of drugs is commonly used as an anti-glaucoma or diuretic agent, particular attention should be paid when initiating topiramate to a patient with a history of sulfonamide or sulfamate induced agranulocytosis, or when co-administrating topiramate with sulfonamides and sulfamates including carbonic anhydrase inhibitors.

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  • Competing interests: none.

  • Patient consent: Patient/guardian consent was obtained for publication

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