A 42-year-old woman on venlafaxine (SNRI) for major depressive disorder presents with severe hypertension, diaphoresis, and tachycardia after starting linezolid for VRE infection. The most appropriate immediate management is:

• A Discontinue linezolid and switch to an alternative antibiotic; give cyproheptadine if serotonin syndrome is severe ✓
• B Reduce the venlafaxine dose and continue linezolid
• C Add propranolol to control the hypertension and tachycardia
• D Switch venlafaxine to bupropion which lacks serotonergic activity

Explanation

This presentation is consistent with serotonin syndrome from the combination of venlafaxine (SNRI, blocks serotonin reuptake) with linezolid (MAO-A inhibitor), resulting in excessive synaptic serotonin. The offending combination must be stopped immediately; cyproheptadine, a 5-HT2A antagonist, is used as adjunct therapy in severe cases. Propranolol addresses only symptoms without resolving the underlying excess serotonin tone. Switching antibiotics rather than antidepressants is appropriate as the infection requires urgent treatment.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.