A bronchodilator medicine that opens the airways by relaxing
the muscles around the airways that may tighten during an asthma attack or in COPD
(chronic obstructive pulmonary disease). Beta-agonists can be administered by inhalers
or orally. They are called "agonists" because they activate the beta-2 receptor
on the muscles surrounding the airways. Activation of beta-2 receptors relaxes the
muscles surrounding the airways and opens the airways. Dilating airways helps to
relieve the symptoms of dyspnea (shortness of breath). Beta-2 agonists have been
shown to relieve dyspnea in many asthma and COPD patients. The action of beta-2
agonists starts within minutes after inhalation and lasts for about 4 hours. Because
of their quick onset of action, beta-2 agonists are especially helpful for patients
who are acutely short of breath but, because of their short duration of action,
several doses of beta-agonists are often necessary each day. The side effects of
beta-2 agonists include anxiety, tremor, palpitations or fast heart rate, and low
blood potassium.
Examples of beta-2 agonists include albuterol (Ventolin, Proventil), metaproterenol
(Alupent), pirbuterol (Maxair), terbutaline (Brethaire), isoetharine (Bronkosol),
and Levalbuterol (Xopenex). Beta-2 agonists with a slower onset of action but a
longer period of activity such as salmeterol xinafoate (Serevent) are now available.
Salmeterol has a duration of action of twelve hours and need only be taken twice
a day.
medical
dictionary, online medical dictionary, medical
terminology dictionary, free online medical
dictionary, medical dictionary, online medical
dictionary, medical terminology dictionary, free
online medical dictionary, dictionary medical,
dictionary medical online, dictionary medical
terminology, dictionary free medical online,
dictionary free medical, dictionary medical
terms, dictionary drug medical medicine,
dictionary health illustrated medical nursing
profession stedmans, dictionary English medical,
dictionary medical online terminology,
dictionary encyclopedia medical online,
condition dictionary medical, dictionary
medical, dictionary drug medical, medical
dictionary software, cyclopedic dictionary index
medical tabers thumb, medical dictionary, online
medical dictionary, medical terminology
dictionary
