Linezolid in combination with pentazocine causes serotonin syndrome: A case report

Serotonin syndrome (SS) is a potentially life-threatening condition characterized by autonomic and muscular hyperactivity resulting from the use of serotonergic drugs that bind to peripheral or central postsynaptic serotonin receptors. This syndrome can be easily confused with other clinical conditions, leading to delays in diagnosis and jeopardizing vital prognosis. Linezolid is utilized in the clinical management of gram-positive coccal infections, while pentazocine, an opioid analgesic, is frequently employed for pain relief in trauma patients. Currently, there are limited reports documenting the occurrence of SS associated with linezolid and pentazocine. In this report, we present the case of a 32-year-old man who developed SS following simultaneous administration of linezolid and pentazocine; his symptoms were effectively managed upon discontinuation of these medications.

A 32-year-old male patient was treated with pentazocine and linezolid for pain management related to trauma as well as for a gram-positive coccal infection. One hour after administration, he exhibited tremors in his right limb along with hand tremors, profuse sweating, and sinus tachycardia; his body temperature subsequently rose to 40°C. Laboratory tests including white blood cell count, procalcitonin levels, and C-reactive protein, showed no significant changes compared to previous results. A follow-up computed tomography scan of the head revealed no new ischemic lesions.

The patient's physical examination, vital signs, and laboratory results were consistent with SS.

Linezolid and pentazocine were discontinued immediately. Midazolam (3-6 µg/kg/h) and dexmedetomidine (0.1-0.3 µg/kg/h) were administered, and oral diazepam (2.5 mg 3 times daily) was gradually continued.

Following this treatment regimen, the patient's profuse sweating improved significantly, and he became stable overall; his body temperature gradually returned to normal levels. Subsequently, the patient was transferred from the surgical intensive care unit to a general ward after 7 days of treatment.

Although SS is not very common in patients using pentazocine and linezolid separately, it is important because it is an emergency condition that can result in death if not treated appropriately. This clinical case highlights the importance of thoroughly understanding the clinical manifestations of SS to ensure early and appropriate treatment management.