Paxil, First Antidepressant Cleared by FDA for Panic Disorder

PHILADELPHIA, May 7, 1996 --

PaxilŽ (paroxetine hydrochloride) was cleared by the U.S. Food and Drug Administration today for the treatment of panic disorder, SmithKline Beecham announced. Panic disorder is a chronic, disabling condition that will affect 3 to 6 million Americans at some time in their lives.

PaxilŽ is the first and only antidepressant indicated for treating panic disorder and the first new drug therapy to be cleared for panic disorder in nearly a decade. PaxilŽ belongs to the class of antidepressants known as selective serotonin reuptake inhibitors (SSRIs).

"In clinical trials, at end point, three out of four patients treated with PaxilŽ were free of full panic attacks," said David Wheadon, MD, vice president of CNS Products, Clinical Research and Development at PaxilŽ. "We believe that PaxilŽ will provide physicians the ability to significantly relieve the symptoms of this disorder and get their patients' lives back on track."

Panic disorder is characterized by recurrent panic attacks. A panic attack is a sudden, unprovoked episode in which sufferers experience physical symptoms such as a racing, pounding heartbeat, chest pain, breathlessness, and choking and may fear they are losing control or are in imminent danger of dying. Panic disorder is diagnosed when a person has:

-- persistent anxiety about having another attack,

-- concern over the implications of the attacks or their consequences, including fear of life-threatening illness or "losing control," and

-- behavioral changes due to the attacks, including avoidance of everyday activities.

"The clinical studies showed that PaxilŽ provides effective short- and long-term treatment for panic disorder," said Jack Gorman, MD, professor of clinical psychiatry at Columbia University. "Many patients suffer for years with this chronic condition before being diagnosed, and long-term therapy is often needed."

Women are twice as likely as men to suffer from panic disorder, and the most common age of onset is the late teens and early twenties. Yet, panic attacks and panic disorder are found in people of all ages. Despite its prevalence, panic disorder is underdiagnosed, according to the National Institute of Mental Health, which estimates that only one out of three panic disorder sufferers have been correctly diagnosed and treated.

Clinical Trials

In one 10-week double-blind clinical study, 76% of patients treated with 40 mg per day of PaxilŽ were completely free of full panic attacks at the end point, compared with 44% of patients who received placebo. Patients who responded to PaxilŽ during the initial 10-week phase and a 3-month double-blind extension phase were randomly assigned to continue on PaxilŽ or be switched to placebo for an additional 3 months. Of the patients switched to placebo, 30% experienced a relapse, as compared with only 5% of those who were treated with PaxilŽ.

PaxilŽ was well tolerated in clinical trials. Side effects with an incidence of 10% or greater and at least twice that of placebo were abnormal ejaculation, sweating, and weakness.

Advantages of Paxil

For many years, the only drug indicated for panic disorder was the benzodiazepine tranquilizer alprazolam. However, alprazolam is associated with dependence and is not indicated for long-term treatment of this chronic condition; nevertheless, until today physicians have had little alternative. Now, however, they can prescribe PaxilŽ, which has not been associated with the development of dependence in clinical trials and is indicated for long-term treatment of panic disorder.

In addition, alprazolam is not indicated for major depression, and as many as 65% of patients with panic disorder may also suffer from depression. PaxilŽ is indicated for the treatment of depression as well as panic disorder.

For the treatment of panic disorder, the recommended target dose of PaxilŽ is 40 mg per day. The starting dose is 10 mg per day, and dosage should not exceed 60 mg per day. PaxilŽ is available in 10-, 20-, 30-, and 40-mg tablets.

Indication for Obsessive-Compulsive Disorder

PaxilŽ also received FDA marketing clearance today for the treatment of obsessive-compulsive disorder (OCD). Obsessions are recurrent and persistent thoughts that are intrusive and inappropriate, as well as distressing or anxiety-provoking. Compulsions are repetitive behaviors such as hand-washing or mental acts such as repeating words silently, and are aimed at reducing the distress or preventing some dreaded event.

PaxilŽ is the only SSRI that has demonstrated long-term maintenance of efficacy in a six-month relapse-prevention clinical trial. This is important because OCD is a chronic condition and often requires long- term treatment.

PaxilŽ was also well-tolerated in clinical trials in OCD. In these trials, side effects with an incidence of 10% or greater and at least twice that of placebo were sleepiness, nausea, abnormal ejaculation, dry mouth, constipation, dizziness and tremor.

The recommended dosage of PaxilŽ in the treatment of obsessive-compulsive disorder is 40 mg daily. The starting dose is 20 mg per day, and dosage should not exceed 60 mg per day