Venlafaxine as single therapy associated with hypertensive encephalopathy

Introduction: Hypertensive encephalopathy with the clinicoradiological entity posterior reversible encephalopathy syndrome in the setting of venlafaxine as single therapy has not been reported earlier.

Case description: A 46-year-old man developed hypertensive encephalopathy associated with venlafaxine as single therapy. Magnetic resonance imaging of the brain, pre and post gadolinium, carried out on day 2, displayed an increased T2 signal in the cortex on both the T2 and FLAIR images throughout the frontal and temporal lobes and in the cerebellum. Venlafaxine therapy was stopped. The patient gradually improved and he became seizure free and the blood pressure successively became normal. A magnetic resonance imaging after six weeks displayed marked regression of the abnormalities. On follow-up after 3 months, his blood pressure had been normal and he had not had any symptoms. The prescribed antiepileptic drug was discontinued as well as antihypertensive treatment. He had not experienced any new symptoms at follow-up after one year.

Discussion and evaluation: The patient in this report had hypertensive encephalopathy associated with venlafaxine therapy. The imaging findings are compatible with hypertensive encephalopathy/posterior reversible encephalopathy syndrome. Venlafaxine is a drug used very frequently. Venlafaxine may infrequently induce hypertensive crisis.

Conclusion: Hypertensive encephalopathy may rarely occur in the setting of venlafaxine as single therapy even in low to moderate doses. Patients on venlafaxine should have regular monitoring of blood pressure. Knowledge of the side effects is vital. Venlafaxine must be discontinued if significant hypertension persists.