LEUKOTRIENE INHIBITORS
Leukotriene
inhibitors block the action of leukotrienes, which are produced by mast cells (like
histamine) and released when the cells are activated. When leukotrienes are
released, inflammation develops in the bronchial tubes causing worsening of
the diseases. These medications have been found to be useful in the
treatment of asthma, nasal allergies and excercise induced
bronchocontriction.
Zyflo – Zileuton
Accolate – Zarfirlukas
Singulair - Montelukast
Drug
Action
Zyflo
interferes with the early formation of leukotrienes in the body by blocking an
enzyme, thus
lessening the amount of inflammation present in the bronchial tubes.
Accolate and Singulair
are eukotriene receptor antagonists. They compete with leukotrienes at the receptor sites in the body; in turn
preventing leukotrienes from having an affect in the bronchial tubes.
Side Effects
Zyflo is generally well tolerated. Side effects may include abdominal
pain, indigestion, and nausea. A small number of people may experience an
increase in liver enzymes and therefore, blood tests for liver function should
be monitored occasionally.
Accolate is also well tolerated. Side effects may
include headaches and elevation in liver enzymes. Blood test to check
liver function should be monitored periodically.
Singulair is also well tolerated. Side effects are rare and may include
headaches and sore throat.
Dosing
Zyflo is usually taken 4 times a day.
Accolate is usually taken twice a day and should be taken 1 hour before or 2 hours after meals.
Singulair is given once a day and works best when taken in the evening. It is approved for patients ages 1 year and over.
Indications
for Use
(of all leukotriene
inhibitors)
All
three drugs are intended to be used as preventative medication and are
indicated in the treatment of acute asthma attacks.
Additional Comment
Both Zyflo and Accolate may need to be taken for several weeks to
evaluate their effectiveness.
Zyflo is contraindicated in people in people with active liver
disease. Even in normal people, liver enzymes need to be checked routinely. Caution should be taken when giving Accolate in people with liver
disease. It is not contraindicated, but dosages should be monitored closely.
Drug Interactions (of all leukotriene inhibitors)
Zyflo may increase levels
theophylline in the body. Therefore, the dose of theophylline should be
decreased and blood levels should be monitored. Caution should be taken
wit the co-administration of Zyflo with propanalol (Inderal), calcium channel
blockers, cyclosporine, cisapride (Propulsid), and astemizole (Hismanal). Caution should also be
taken with the administration of Accolate or Zyflo with Warfarin (Coumadin)
and Warfarin levels should be closely monitored.