Dose-dependent Venlafaxine-induced sinus tachycardia

Abstract

A 31-year-old woman had suffered with depression for several years. In January 2000, she was commenced on Venlafaxine 75 mg BD. She started to complain of palpitation following titrating up of her Venlafaxine therapy to 75 mg TDS in March 2001. Eventually, she stopped her Venlafaxine therapy in September 2001 due to recurrent palpitation. Unfortunately, she started to experience a significant deterioration in her mood and depression disorder without any response to other antidepressants. As a result, she was re-commenced again on Venlafaxine 75 mg OD in February 2002. She did not develop any symptoms of palpitation on this dose. However, she started to develop palpitation again on titrating her Venlafaxine dose to 75 mg BD in July 2004. She was reviewed in the cardiology outpatient clinic in March 2005 where she continued to complain of recurrent regular palpitation. She did not complain of breathlessness, orthopnea, or paroxysmal nocturnal dyspnoea. There was no history of warning symptoms and no other precipitating factors. She had no past medical history of heart or thyroid disease and she was not on any other regular medications. She drank very little alcohol but suffered with mild asthma.