Medical Safety

Paroxetine treatment in clinical trials has not been associated with any significant abnormalities in standard laboratory tests, including hematological indices and chemistry panels, electroencephalogram (EEG), or electrocardiogram (ECG). One possible concern regarding paroxetine had been the potential for decreased heart rate variability (HRV), because depressed patients have been shown to exhibit lower HRV than nondepressed persons and this decrease represents a significant risk factor for myocardial infarction (Gorman and Sloan 2000). Moreover, NE reuptake-inhibiting antidepressant drugs have been shown to cause further decreases in this electrophysiological variable (Rechlin 1994). Decreases in HRV have been implicated in increased cardiovascular mortality (Carney et al. 2005), and depression itself has been conclusively shown to be a risk factor in the development of heart disease (Musselman et al. 1998). Davidson et al. (2005) demonstrated that paroxetine (doses up to 40 mg/day) resulted in lower NET occupancy compared with venlafaxine XR (doses up to 225 mg/day). In contrast to venlafaxine, paroxetine had no effect on HRV, as measured by changes in R-R interval during forced 10-second breaths and respiratory sinus arrhythmia (RSA) during paced breathing. Further comparisons of the effects of antidepressant medications on HRV are warranted.

Paroxetine and other SRIs have been implicated in precipitation of the syndrome of inappropriate antidiuretic hormone (SIADH), particularly in elderly individuals, which resolves on discontinuation of the medication (Strachan and Shepherd 1998). The potential for paroxetine-induced hyponatremia was prospectively evaluated in a 12-week open trial involving depressed male and female subjects between the ages of 63 and 90 years (Fabian et al. 2004). Hyponatremia, defined as plasma sodium levels lower than 135 mEq per liter, developed in 9 of the 75 total subjects (12%), in most cases within 10 days of initiation. Risk factors for developing hyponatremia were low body mass index (BMI) and low starting plasma sodium levels. These results underscore the importance of monitoring electrolytes closely in geriatric patients treated with paroxetine and other antidepressants.

Anxiety and Depression 101

Anxiety and Depression 101

Everything you ever wanted to know about. We have been discussing depression and anxiety and how different information that is out on the market only seems to target one particular cure for these two common conditions that seem to walk hand in hand.

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