Serotonin syndrome induced by fluvoxamine and oxycodone

Area of Science:

• Pharmacology
• Clinical Toxicology
• Neuroscience

Background:

• Serotonin syndrome is a potentially life-threatening condition caused by excessive serotonergic activity.
• Drug interactions are a common cause of serotonin syndrome, particularly with serotonergic agents.
• Oxycodone, an opioid analgesic, has been rarely implicated in serotonin syndrome compared to other analgesics.

Observation:

• A 70-year-old woman developed severe serotonergic symptoms, including confusion, fever, and hypertonia.
• These symptoms emerged after initiating oxycodone (40 mg twice daily) in addition to her existing fluvoxamine (200 mg/day) regimen.
• The patient met diagnostic criteria for serotonin syndrome, with symptoms resolving within 48 hours of drug discontinuation.

Findings:

• The Naranjo probability scale indicated a probable link between the patient's symptoms and the combined use of oxycodone and fluvoxamine.
• This case adds to the limited reports of oxycodone-induced serotonin syndrome.
• Unlike some other opioids, oxycodone does not directly inhibit serotonin reuptake, suggesting alternative mechanisms for this interaction.

Implications:

• Clinicians should be vigilant for serotonin syndrome when prescribing oxycodone to patients on fluvoxamine or other serotonergic medications.
• Enhanced monitoring for serotonergic adverse events is crucial in such cases.
• Further research into the pharmacologic mechanisms underlying oxycodone-serotonin interactions may be warranted.