Serotonin syndrome induced by fluvoxamine and oxycodone.
OBJECTIVE
To report a case of severe serotonergic symptoms following the addition of oxycodone to fluvoxamine.


METHODS
A 70-year-old woman developed severe serotonergic features, including confusion, nausea, fever, clonus, hyperreflexia, hypertonia, shivering, and tachycardia, following the addition of oxycodone 40 mg twice daily to fluvoxamine 200 mg/day, easily fulfilling diagnostic criteria for serotonin syndrome. Discontinuation of the offending drugs resulted in resolution of her symptoms over 48 hours, and no other cause of the syndrome was identified. Use of the Naranjo probability scale indicated a probable relationship between the serotonergic symptoms and the addition of oxycodone to fluvoxamine therapy.


CONCLUSIONS
Serotonin syndrome is a serious adverse reaction usually due to interactions with serotonergic drugs. There have been only 3 previous reports involving oxycodone. Most previous reports of serotonin syndrome involving analgesics have been associated with meperidine, dextromethorphan, and tramadol. Unlike these synthetic opioids, however, oxycodone does not inhibit the reuptake of serotonin. In addition, there are a number of other possible pharmacologic mechanisms for the interaction we observed.


CONCLUSIONS
Monitoring for serotonergic adverse events should be done when oxycodone is given to patients receiving serotonin-reuptake inhibitors.
Karunatilake
Harindra
H
The Canberra Hospital, Canberra, New South Wales, Australia.
Buckley
Nicholas A
NA
D000368:Aged; D000701:Analgesics, Opioid / Q000009:adverse effects / Q000627:therapeutic use; D003863:Depression / Q000188:drug therapy; D004347:Drug Interactions; D005260:Female; D016666:Fluvoxamine / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D010098:Oxycodone / Q000009:adverse effects* / Q000627:therapeutic use; D010146:Pain / Q000188:drug therapy; D020230:Serotonin Syndrome / Q000139:chemically induced* / Q000503:physiopathology; D017367:Selective Serotonin Reuptake Inhibitors / Q000009:adverse effects / Q000627:therapeutic use
D000701:Analgesics, Opioid; D016666:Fluvoxamine; D010098:Oxycodone; D017367:Selective Serotonin Reuptake Inhibitors