Uses and Administration
Fenoterol/Berotec is a direct-acting sympathomimetic with beta-adrenoceptor stimulant activity largely selective for beta2 receptors (a beta2 agonist). It has actions and uses similar to those of salbutamol/ventolin and is used as a bronchodilator in the management of reversible airways obstruction, as occurs in asthma and in some patients with chronic obstructive pulmonary disease. Following inhalation, fenoterol acts rapidly (2 to 3 minutes) and has a duration of action of about 6 to 8 hours.
In the management of reversible airways obstruction, fenoterol hydrobromide may be administered by inhalation in a dose of 1 or 2 inhalations of 100 micrograms up to 3 or 4 times daily; children over the age of 6 years will only normally require one inhalation (100 micrograms) up to 3 times daily. If symptoms are not adequately controlled with this low-dose inhaler then a high-dose inhaler administering 200 micrograms per inhalation has been employed in adults; 2 inhalations of 200 micrograms may be given up to 3 times daily.
The dose should not exceed 400 micrograms every six hours or 1.6 mg in a 24-hour period; this high-dose inhaler is not recommended for children under 16 years of age. Current asthma guidelines recommend that inhaled short-acting beta2 agonists such as fenoterol be used on an ‘as-required’, not regular, basis. In those patients requiring more than occasional use of fenoterol/Berotec, anti-inflammatory therapy is also needed. An increased requirement for, or decreased duration of effect of, fenoterol indicates deterioration of asthma control and the need for increased anti-inflammatory therapy.
Fenoterol hydrobromide may be given as a nebulised solution; the usual dose for inhalation by this route is 200 to 400 micrograms, up to a maximum of 1.6 mg daily.
Fenoterol hydrobromide has also been used similarly to salbutamol in the management of premature labour. A suggested dose, by intravenous infusion, has been 0.5 to 3 micrograms/minute, continued until contractions are suppressed, and followed by oral administration of 5 mg every 3 to 6 hours. Fenoterol is also available as a syrup.