Zolpidem-associated hallucinations and serotonin reuptake inhibition: a possible interaction.
BACKGROUND
Zolpidem (Ambien) is a sedative believed to act exclusively at the benzodiazepine omega 1 receptor. Sporadic case reports of zolpidem-associated hallucinations have appeared over the past 5 years, and over the past 2 years, the Washington Poison Center received five reports of prolonged visual hallucinations associated with zolpidem.


METHODS
All five patients reported experiencing visual hallucinations lasting from 1-7 hours soon after taking zolpidem. Most had been taking zolpidem for less than a week and all five were concurrently taking an antidepressant: sertraline, desipramine, fluoxetine, bupropion, or venlafaxine; two sought assistance at a hospital.


CONCLUSIONS
The precise mechanism of zolpidem-associated hallucinations remains unknown. In some previously published cases, the zolpidem-associated hallucinations have been short in duration, lasting at most 30 minutes. In contrast, the five patients in our series and in five previously reported cases, the hallucinations were more persistent, lasting up to 7 hours. Of these ten cases with persistent symptoms, nine were concurrently taking antidepressants that inhibit serotonin-reuptake, despite the fact that zolpidem has no known serotonin-mediated mechanisms.


CONCLUSIONS
These cases, plus prior case reports, suggest that a pharmacodynamic interaction between serotonin reuptake inhibition and zolpidem may lead to prolonged zolpidem-associated hallucinations in susceptible individuals.
Elko
C J
CJ
Washington Poison Center, Seattle 98125-8012, USA. elko@wapc.org
Burgess
J L
JL
Robertson
W O
WO
D000293:Adolescent; D000328:Adult; D000928:Antidepressive Agents / Q000009:adverse effects*; D003863:Depression / Q000188:drug therapy; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D006212:Hallucinations / Q000139:chemically induced*; D006801:Humans; D006993:Hypnotics and Sedatives / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011725:Pyridines / Q000009:adverse effects*; D017367:Selective Serotonin Reuptake Inhibitors / Q000009:adverse effects*; D000077334:Zolpidem
D000928:Antidepressive Agents; D006993:Hypnotics and Sedatives; D011725:Pyridines; D017367:Selective Serotonin Reuptake Inhibitors; D000077334:Zolpidem