Reversible granulocytopenia in association with riluzole therapy.
OBJECTIVE
To report a case of severe neutropenia developing in association with riluzole 200 mg/d.


METHODS
A 63-year-old woman with amyotrophic lateral sclerosis (ALS) presented with nausea, anorexia, and fever two weeks following inadvertent dose escalation of riluzole from 100 to 200 mg/d. Granulocytopenia was diagnosed and evaluation for a possible causative infectious process was negative; riluzole was considered a possible offender. Blood counts returned to normal with discontinuation of riluzole and administration of filgramstim.


CONCLUSIONS
Riluzole is a glutamate release inhibitor used in the treatment of ALS, a devastating, progressive neurodegenerative disorder affecting motor neurons. A variety of adverse effects have been described with riluzole therapy, most commonly dizziness and gastrointestinal disorders. In this patient, multiple investigations failed to reveal an infectious cause or other drug-induced cause for the granulocytopenia.


CONCLUSIONS
Granulocytopenia has been reported as an adverse effect of riluzole but is not a complication well known to clinicians, and there are no detailed reports published in the literature. In this patient, several lines of evidence raise the possibility of a causal relationship between riluzole and granulocytopenia.
Department of Neurology, University of Connecticut Health Center, Farmington, USA. north@nso.uchc.edu
W A
WA
North
A M
AM
Khan
H T
HT
Yamase
J R
JR
Sporn
D000380:Agranulocytosis / Q000097:blood / Q000139:chemically induced*; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications / Q000188:drug therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D018696:Neuroprotective Agents / Q000009:adverse effects* / Q000627:therapeutic use; D009503:Neutropenia / Q000097:blood / Q000139:chemically induced; D019782:Riluzole / Q000009:adverse effects* / Q000627:therapeutic use
D018696:Neuroprotective Agents; D019782:Riluzole