Aerospan tm (flunisolide hfa, 80 mcg) Inhalation Aerosol For Oral Inhalation Only Rx Only description

CLINICAL PHARMACOLOGY 
Mechanism of Action:
Flunisolide has demonstrated marked anti-inflammatory activity 
in classical test systems. It is a corticosteroid that is several hundred times more potent 
than cortisol in animal anti-inflammatory assays, and several hundred times more potent 
than dexamethasone in anti-inflammatory effect as determined by the McKenzie skin 
blanching test. The clinical significance of these findings is unknown.
Airway inflammation in both large and small airways is an important component in the 
pathogenesis of asthma. Corticosteroids have been shown to have a wide range of anti-
inflammatory effects, inhibiting both inflammatory cells and release of inflammatory 
mediators. It is presumed that these anti-inflammatory actions play an important role in 
the efficacy of flunisolide in controlling symptoms and improving lung function in 
asthma. Inhaled flunisolide probably acts topically at the site of deposition in the 
bronchial tree after inhalation.
 
Pharmacokinetics:
All the data described below is based on studies conducted in subjects 18 to 51 years of 
age. 
Absorption:
Flunisolide is rapidly absorbed after oral inhalation. Mean values for the 
time to maximum concentration, T
max
, of flunisolide range from 0.09 to 0.17 hr after a 
single 320 mcg dose of AEROSPAN Inhalation Aerosol. The corresponding mean 
values for the maximum concentration, C
max
, of flunisolide vary from 1.9 to 3.3 ng/mL.

Oral bioavailability is less than 7%. Over the dose range of 80 mcg to 320 mcg of 

AEROSPAN Inhalation Aerosol, values for C
max
increase proportionately with dose after 
single as well as multiple dose administration.
Distribution:
Flunisolide is extensively distributed in the body, with mean values for 
apparent volume of distribution ranging from 170 to 350 L after a single 320 mcg dose of 
AEROSPAN Inhalation Aerosol.
Metabolism:
Flunisolide is rapidly and extensively converted to 6ß-OH flunisolide and 
to water-soluble conjugates during the first pass through the liver. Conversion to 6ß-OH 
flunisolide, the only circulating metabolite detected in man, is thought to occur via the 

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cytochrome P450 enzyme system, particularly the enzyme CYP3A4. 6ß-OH flunisolide 
has a low corticosteroid potency (ten times less potent than cortisol and more than 200 
times less potent than flunisolide). Maximum levels of 6ß-OH flunisolide were 0.66 
mcg/mL after a single 320 mcg dose of AEROSPAN Inhalation Aerosol, and 0.71 
mcg/mL after multiple doses of AEROSPAN Inhalation Aerosol. 
Excretion:
Urinary excretion of flunisolide is low. Less than 1% of the administered 
dose of flunisolide is recovered in urine after inhalation. The half-life values for 6ß-OH 
flunisolide range from 3.1 to 5.1 hrs after administration of AEROSPAN Inhalation 
Aerosol in the dose range of 160 mcg to 320 mcg.