Dose-related paresthesias with venlafaxine.

INTRODUCTION

Venlafaxine is a serotonin norepinephrine reuptake inhibitor that is used for mood, anxiety, and pain disorders. We report a case of dose-related paresthesias in association with venlafaxine use in a patient with major depressive disorder.

CASE REPORT

A young male patient with major depression started treatment with venlafaxine XR at 37.5 mg/d, and the dose was titrated to 75 mg/d with no significant adverse effects. Upon increasing the dose to 150 mg/d, the patient reported tingling, numbness, and itching in his upper extremities. The dose was reduced to 75 mg/d, at which time, the symptoms disappeared. Since the patient still had target symptoms of depression, the patient was willing to try increasing the dose back to 150 mg/d. Upon rechallenge, the tingling, numbness, and itching reappeared. The dose of venlafaxine was decreased back to 75 mg/d. Per the Naranjo scale, the probability score for the above adverse drug reaction is 5 (probable). We discuss the published evidence of paresthesias associated with antidepressants and clinical implications for recognizing paresthesias during venlafaxine treatment that may be useful for clinicians.

CONCLUSION

Clinicians need to be aware of the possible emergence of paresthesias with venlafaxine treatment, especially at doses of ≥ 150 mg/day. Patients who receive venlafaxine for pain disorders should be closely monitored for worsening of pain symptoms and may require adjustment of their doses.