Chemistry and pharmacology
Roflumilast and its active metabolite
(roflumilast N-oxide) are
selective PDE-4 inhibitors.6 PDE-4 is
a member of the phosphodiesterase
superfamily and is responsible for the
inactivation of the secondary messenger
cyclic adenosine monophosphate
(cAMP) found in proinflammatory
and immune-competent cells
in the lungs. PDE-4 inhibitors result
in antiinflammatory effects by preventing
the breakdown of cAMP, allowing
it to activate protein kinase A.
The antiinflammatory effects include
reducing the release of inflammatory
mediators from neutrophils, monocytes,
and cytokines from CD8 and
CD4 T cells; inhibiting fibrotic lung
remodeling; and decreasing oxidative
stress.5,7 Human studies have demonstrated
that roflumilast may reduce
the number of neutrophils, other inflammatory
cells, and inflammatory
markers in the sputum and bronchial
airways of healthy volunteers.8,9