TORONTO - With the federal go-ahead to prescribe the selective serotonin reuptake inhibitor (SSRI) paroxetine in the treatment of chronic panic attacks, experts hope to heighten awareness of this often-undetected disorder.
Panic disorder is a relatively common, severe and disabling illness but it's diagnosed in only 20% of cases said Dr. Jacques Bradwejn, head of the psychobiology and clinical trials research unit in anxiety at The Clarke Institute of Psychiatry, and professor of psychiatry at the University of Toronto.
The approval of the drug for panic disorder provides an opportunity to "address" the disorder and educate the public and medical profession, said Dr. Bradwejn.
However, it may not change prescribing habits.
Doctors should "have a high index of suspicion" when patients come into the office or emergency room displaying symptoms such as nausea, dizziness, shortness of breath, or chest pain, especially if they have signs of agoraphobia, Dr. Bradwejn said. As many as 65% of panic disorder patients experience some degree of agoraphobia.
"Doctors can easily ask patients questions such as 'Do you avoid going to public places?' and right away formulate a diagnosis" when standard tests for things like cardiac involvement are negative, he said.
Unlike some of the products used to treat panic disorder, paroxetine (manufactured by SmithKline Beecham Pharma under the brand name Paxil) is nonsedating and nonaddictive, said Dr. Robin Reesal, president and medical director of the Western Canada Behavior Research Centre at the WHO Centre for Research and Training in Mental Health in Calgary.
Dr. Reesal added that paroxetine is also safe when combined with alcohol.
Traditional pharmaco-therapies for panic disorder include benzodiazepines, monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants.
Drs. Bradwejn and Reesal were among the speakers at a press conference to announce the approval of paroxetine in panic disorder. Also on hand were two patients afflicted with the disorder.
Many such patients have a "hypersensitivity" to a natural brain protein called cholecystokinin (CCK), said Dr. Bradwejn, who is currently a principal investigator of a study into the neurobiology of anxiety disorders.
The neurotransmitter serotonin is also involved in the disorder. Like other SSRIs, paroxetine increases the level of serotonin by blocking its reuptake at the nerve junctions, thus ensuring nerve cells continue to be stimulated.
Paxil has already been approved for obsessive compulsive disorder and depression, conditions which are also linked to malfunctions in the serotonin system.
Using the drug in panic disorder warrants a unique approach, said Dr. Bradwejn. "You have to start with a much lower dose," perhaps 5 mg or 10 mg three to four times a week rather than 20 mg a day that might be prescribed for depression.
The efficacy rate of this drug is about 80% when it's "started slow and brought to right dosage," he said, adding it makes no difference to the efficacy rate whether patients are depressed or not.
Despite its promising profile in treating panic attacks, paroxetine does have some side effects, said Dr. Reesal. These include sexual dysfunction in 15% to 20% of patients and gastrointestinal upset in 10% to 15% although, these symptoms often disappear with time.
The drug is cost-effective, added Dr. Reesal. Many of these patients appear in the emergency room complaining of chest pain and get the "million dollar work up" that includes electrocardiograms (ECGs) and other tests.
These patients have eight times more consultations and tests than the general population and it takes about 10 visits to cardiologists, neurologists, gastroenterologists and others for up to six years before a proper diagnosis is made, added Dr. Bradwejn. They also seek help from other health professionals, including behavior and exercise therapists.
Ron, who has suffered from the disease for almost 15 years, spent many of those years visiting health professionals to try to find out what was wrong with him. He said an early diagnosis would have prevented years of hell.
"A lot of people don't know how to treat this disorder, even if they have a lot of letters after their name," he said.
Ron is among the approximately 5% to 10% of the population who suffers from panic attacks, and the 2% to 4% diagnosed with the more chronic panic disorder. He was 23 years old when he had his first attack; age of onset is normally in the 20s or 30s. Women are about three times more at risk than men.
During a panic attack, patients typically experience shortness of breath, nausea, chills and feelings of anxiety, disorientation and the fear that they're "going to die." The attack can last from a few minutes to more than 20 minutes. Some patients have attacks several times a day.
Many patients become "demoralized" because of their decreased ability to function, said Dr. Bradwejn. Some patients self treat with alcohol or sedatives. As many as 40% suffer from major depression.
Researchers believe there's a genetic component to panic disorder. Studies show anxiety disorders in general are five times as common in identical twins as nonidentical twins.
While the approval of Paxil for panic disorder may heighten awareness about this psychiatric problem, it probably won't noticeably change physician prescribing habits, said Dr. Richard Swinson, head of the anxiety disorder program at The Clarke Institute of Psychiatry, and professor of psychiatry, University of Toronto.
Most of his patients recover with only cognitive behavior treatments instead of medication therapy. Pharmaceuticals, such as SSRIs, are prescribed only when a patient suffers from depression as well as panic disorder, or when behavior therapy has failed or been refused by the patients, Dr. Swinson said.
When medication is indicated, Dr. Swinson said he probably prescribes Paxil as often as any SSRI. "Is Paxil as good as other medications? Probably. Is it better? Probably not."
Copyright © 1996 Maclean Hunter Publishing Limited
Reprinted with permission.
Internet Mental Health (www.mentalhealth.com) copyright © 1995-2011 by Phillip W. Long, M.D.