Toxic delirium in a patient taking amantadine and trimethoprim-sulfamethoxazole.
Acute mental confusion occurred in a patient on a stable dose of amantadine after he was started on trimethoprim-sulfamethoxazole. Discontinuation of the drugs led to rapid improvement. Studies in a rat model of organic cation secretion demonstrate that both amantadine and trimethoprim, but not sulfamethoxazole, inhibit the renal secretion of the organic cation procainamide. This case may represent an amantadine-trimethoprim interaction.
Speeg
K V
KV
Department of Medicine, University of Texas Health Science Center, San Antonio 78284.
Leighton
J A
JA
Maldonado
A L
AL
D000368:Aged; D000547:Amantadine / Q000009:adverse effects* / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D003693:Delirium / Q000139:chemically induced*; D004347:Drug Interactions; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008297:Male; D011342:Procainamide / Q000378:metabolism; D013420:Sulfamethoxazole / Q000009:adverse effects*; D014295:Trimethoprim / Q000009:adverse effects*
D014295:Trimethoprim; D000547:Amantadine; D013420:Sulfamethoxazole; D011342:Procainamide