K. George Thampy M.D              ST. LOUIS UNIVERSITY
Gentamicin-induced acute psychosis
         
 

The most common adverse effect of Gentamicin on the nervous system involves 
the eighth cranial nerve resulting in auditory (loss of hearing, ringing or buzzing, 
or a feeling of fullness in the ears) and or vestibular (clumsiness, dizziness, nausea, 
vomiting and unsteadiness) disturbances. Gentamicin is also known to cause 
encephalopathy and seizures. However, the neuropsychiatric effect of gentamicin are
 extremely rare. Here we describe an 80-year old woman with no previous history of 
psychiatric disorders who developed acute psychosis within 48 hours after starting
 gentamicin treatment for Enterobacter and Proteus cystitis. A number of potential causes,
 including electrolyte abnormalities, metabolic derangements, myocardial infarction, 
psychotropic drugs, intracranial bleed, stroke, intra-abdominal pathology, were ruled out. 
The patient had normal renal function and therapeutic serum levels of gentamicin during 
the episode. Upon withdrawal of gentamicin her psychosis resolved within 24-48 hours.