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 BRAND NAMES
- International: Berotec
 MECHANISM OF ACTION
Fenoterol is a short-acting Beta2 adrenergic receptor agonist.
Beta2 receptors are the predominant adrenergic receptors in bronchial smooth muscle. The binding of Fenoterol to Beta2 adrenergic receptors in bronchial smooth muscle, activates the intracellular adenylate cyclase, an enzyme which catalyzes the conversion of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP). The increase of cAMP determines:
- Bronchodilation: Increased intracellular cyclic AMP (cAMP), increases the activation of cAMP-dependent protein kinase A, which inhibits the phosphorylation of myosin and lowers intracellular calcium levels within the muscle. Lower levels of calcium cause relaxation of the smooth muscle and therefore bronchodilatation.
- Inhibition of the release of mast cell mediators.
- Increased mucociliary clearance.
In high doses fenoterol also affects the striated muscles (tremor) and the the β1-receptors (heart side effects) and has an influence on lipid and sugar metabolism (lipolysis, glycogenolysis and hyperglycaemia) and relative hypokalaemia due to increased K+ uptake in the skeletal muscle.
Due to the density of β2-receptors in the myometrium, fenoterol also relaxes the uterine muscles. This effect is particularly pronounced in the pregnant uterus and at considerably higher doses.
Following inhalation, bronchodilatation is induced within a few minutes and the effect persists for 3 – 5 hours.
Fenoterol is used to relieve and prevent bronchospasm associated with asthma, chronic bronchitis, emphysema and other pulmonary disorders where bronchospasm is a complicating factor.
A single dose of one or two inhalations (0.2-0.4 mg) to control bronchospasm. If required, this dose of 1 or 2 inhalations may be repeated up to 4 times daily. With repeated dosing, drug should not be given more often than every 4 hours. Patients should not exceed a total of 8 inhalations per day
 PREGNANCY AND LACTATION
 SIDE EFFECTS
Generally, fenoterol is well tolerated and many people will not experience unwanted effects. The severity and duration of these effects are dependant on many factors including duration of therapy, dose, route of administration and individual response. Possible unwanted effects include:
- slight palpitations
- fine tremor
- bad taste
- increased heart rate
- muscle cramps
Many of these unwanted effects, especially the most common ones, may disappear with continued use.