Venlafaxine-Induced Orthostatic Hypotension in a Geriatric Patient

Venlafaxine is not usually associated with risk of orthostatic hypotension. A 65-year-old US Caucasian female taking 225？mg/day of venlafaxine extended-release developed symptomatic orthostatic hypotension. The systolic and diastolic blood pressure dropped by 25 and 18？mm Hg, respectively, from supine position to standing position within 3 minutes. The patient was otherwise healthy and the orthostatic hypotension resolved with venlafaxine discontinuation. This was a probable venlafaxine adverse drug reaction according to the Naranjo scale. This case contributes to the scarce literature that indicates that clinicians need to be aware that occasionally venlafaxine can induce clinically significant orthostatic hypotension, particularly in geriatric patients. Our patient did not have orthostatic hypotension when she was taking venlafaxine at 60 years of age in higher venlafaxine doses (300？mg/day) but developed this adverse drug reaction when venlafaxine was restarted at the geriatric age. This case indicates that a history of prior tolerance to venlafaxine does not guarantee tolerance after 65 years of age. If a clinician decides to use venlafaxine in geriatric patients, the clinician should warn the patient about the risk of orthostatic hypotension and consider very slow titration and low doses. 1. Introduction The Consensus Committee of the American Autonomic Society and the American Academy of Neurology [1] defined orthostatic hypotension as “a reduction of systolic blood pressure (BP) of at least 20？mm Hg or diastolic BP of at least 10？mm Hg within 3 minutes of standing.” This consensus definition has recently been updated with minor changes [2]. Orthostatic hypotension can be an adverse drug reaction (ADR) to several antidepressants and antipsychotics. These drugs can cause orthostatic hypotension during the first few weeks of treatment but usually tolerance develops. Thus, the risk for hypotension is one of the reasons that slow titration is recommended for some of these drugs. Orthostatic hypotension is usually explained by the alpha-1 antagonistic properties of some antidepressants and antipsychotics [3]. Among antidepressants, several of the tricyclic antidepressants (TCAs) are potent alpha-1 antagonists, but venlafaxine is usually considered to be lacking in antagonist properties at these receptors [3]. Articles focused on venlafaxine cardiovascular ADRs describe venlafaxine as being prone to cause hypertension, but it is not considered to cause orthostatic hypotension [4, 5]. The blockade of the noradrenergic reuptake transporter explains why