Home » Drug Information » FDA Approved Drugs » 1996
Medical Areas: Psychiatry/Psychology | Family Medicine
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Paxil (paroxetine hydrochloride)
The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Company: SmithKline Beecham
Approval Status: Approved May 1996
Treatment Area: panic disorder, obsessive-compulsive disorders
Paxil has been approved for the treatment of panic disorder, a
disabling condition that will affect three to six million Americans
at some time in their lives. Paxil belongs to a class of
antidepressants known as selective serotonin reuptake inhibitors
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. Paxil 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. Paxil is indicated for the treatment of depression
as well as panic disorder.
For the treatment of panic disorder, the recommended target dose
of Paxil is 40 mg per day. The starting dose is 10 mg per day, and
dosage should not exceed 60 mg per day. Paxil is available in 10,
20, 30, and 40 mg tablets.
Paxil has also been approved as treatment for
obsessive-compulsive disorder. 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.
The recommended dosage of Paxil 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.
In one 10-week double-blind clinical study, 76% of subjects
treated with 40 mg per day of Paxil were completely free of full
panic attacks at the end point, compared with 44% of subjects who
received placebo. Patients who responded to Paxil during the
initial 10-week phase and a three-month double-blind extension
phase were randomly assigned to continue on Paxil or be switched to
placebo for an additional three months. Of the subjects switched to
placebo, 30% experienced a relapse, as compared with only 5% of
those who were treated with Paxil.
Paxil 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.
Paxil was well tolerated in clinical trials for panic disorder
and OCD. 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.
Panic disorder is characterized by recurrent panic attacks. A
panic attack is a sudden, unprovoked episode in which sufferers
experience physical symptoms such as 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
- behavioral changes due to the attacks, including avoidance of
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 under
diagnosed, according to the National Institute of Mental Health,
which estimates that only one out of three panic disorder sufferers
has been correctly diagnosed and treated.