Pregabalin is a 3-substituted analogue of gamma-amino butyric acid (GABA) related to the antiepileptic drug gabapentin. Both drugs have similar mechanisms of action, binding to calcium channels and modulating calcium influx, and influencing GABergic neurotransmission, thereby producing analgesic and anxiolytic effects.

Moira A. Rynn, MD, assistant professor of psychiatry and medical director, Mood and Anxiety Disorders Section, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States.

Pregabalin's "robust efficacy" in relieving psychic and somatic anxiety symptoms has been demonstrated in 5 short-term studies and in a 6-month relapse prevention trial, Dr. Rynn said.

To assess the drug's efficacy, safety and tolerability in long term treatment, Dr. Rynn and colleagues evaluated patients who had successfully completed an earlier, short-term trial of pregabalin (200-600 mg/d administered BID) for GAD or SAD in an open-label extension study of 1 year's duration.

The researchers assessed disease severity using the Clinical Global Impression of Severity (CGIS) score (7-point scale) at baseline, week 27, and week 52. They also evaluated treatment safety and tolerability.

The extended study enrolled 148 women and 117 men. Fourteen patients (5.3%) were aged 65 or older. At entry, 44.9% had a CGIS score <4, which denoted minimal to mild anxiety, and 55.1% had a CGIS score of 4 or more, meaning that they were moderately to extremely ill or worse, Dr. Rynn said.

At 1 year, 75.4% of patients were rated as not at all to mildly ill, and 24.6% were rated as moderately ill or worse.

The drug was very well tolerated, Dr. Rynn said, and most adverse events were mild or moderate in severity. The most common adverse effects were dizziness, infection, pharyngitis, and somnolence; 11.3% of patients discontinued treatment because of adverse effects.

The severity of anxiety symptoms tended to decrease with extended pregabalin treatment, Dr. Rynn concluded.


[Presentation title: Pregabalin Sustained Efficacy and Long-Term Safety and Tolerability in the Treatment of Generalized Anxiety Disorder (GAD) and Social Anxiety Disorder (SAD): A 1-Year, Open-Label Study. Abstract 392]

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