Home » Drug Information » FDA Approved Drugs » 1997
Medical Areas: Pulmonary/Respiratory Diseases | Family Medicine
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The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Company: Abbott Laboratories
Approval Status: Approved January 1997
Treatment Area: asthma
Zyflo has been approved for the prevention and chronic treatment
of asthma in patients aged 12 years and older. The recommended
dosage of Zyflo is one 600 mg tablet four times daily, even during
symptom-free periods. Zyflo is available nationwide by
In clinical trials involving patients with mild-to-moderate
asthma who used daily inhaled beta-agonists, Zyflo decreased the
percentage of patients requiring steroid rescues for worsening
asthma compared to patients treated with placebo. Overall, the
percentage of Zyflo patients requiring steroid rescue was 7
percent, compared with 18.7 percent of patients in the placebo
group. This represents a reduction of 62 percent.
In addition, patients receiving Zyflo also were able to reduce
their use of inhaled beta-agonists. At the end of the six-month
study, the number of beta-agonist puffs needed per day was 1.77
puffs, or 31 percent lower than baseline in Zyflo-treated patients;
there was a 0.22 puff decrease in the placebo group. The reduction
in the use of these medications was accompanied by improvements in
Patients’ asthma symptoms improved by 36 percent, and night-time
symptoms improved 31 percent in patients treated with Zyflo. For
placebo-treated patients, improvements were 21 percent and 5
Zyflo should not be used to treat acute episodes of asthma.
Safety data with Zyflo have been gathered from more than 5,500
patients. In asthma studies, the overall incidence of adverse
events was similar between the Zyflo- and placebo-treated groups.
Dyspepsia (upset stomach) was reported significantly more often by
patients treated with Zyflo than with placebo.
Some patients treated with Zyflo experienced elevations in liver
function tests. Patients taking Zyflo should have their liver
function tested prior to taking, and periodically while taking the
medication. Zyflo should not be taken by patients who have active
liver disease or liver enzymes that are elevated. Although liver
function test elevations were observed throughout the treatment
period, the majority (61%) of these elevations developed during the
first two months of treatment. Generally, these abnormalities
resolved or decreased to acceptable levels while treatment
continued or soon after it was stopped. some patients discontinued
treatment with Zyflo because of these elevations.
Doses of theophylline, warfarin, and/or propranolol should be
adjusted and patients monitored when taking Zyflo.
Mechanism of Action
Zyflo, developed by Abbott Laboratories, is a member of a new
class of anti-leukotriene asthma medicines that acts as a
leukotriene pathway inhibitor (LPI) by inhibiting the enzyme
5-lipoxygenase (5-LO). Zyflo inhibits the formation of
leukotrienes. Leukotrienes are molecules that contribute to the
inflammation, swelling (edema), bronchoconstriction (tightening of
muscles wrapped around the outside of the airways) and mucus
secretion seen in the airways of patients with asthma.
Approximately one in 20 Americans has asthma. The symptoms of
asthma include wheezing, coughing, and shortness of breath. From
1982-1992, the annual prevalence of self-reported asthma increased