Fenspiride

General information

Fenspiride is a bronchodilator and anti-inflammatory drug. Two in vitro studies have suggested possible mechanisms for these effects.

Functional studies in human isolated bronchi showed that fenspiride causes a shift to the left of concentration effect curves for relaxation induced by isoprenaline and sodium nitroprusside [ ]. Biochemical studies confirmed that phosphodiesterase type IV (cyclic AMP-specific) and phosphodiesterase type V (cyclic GMP-specific) are the main phosphodiesterase isoforms present in human bronchi. Fenspiride inhibited both isoforms. Fenspiride facilitates relaxation of human bronchial smooth muscle in vitro, and this effect may be due to inhibition of phosphodiesterases IV and V.

In a human lung epithelial cell line, in which histamine increased the intracellular calcium concentration and the formation of eicosanoids, this response was antagonized by the histamine H ₁ receptor antagonist diphenhydramine but unaffected by the H ₂ receptor antagonist cimetidine. Fenspiride inhibited H ₁ receptor-induced calcium increase [ ]. Histamine also caused a biphasic increase in arachidonic acid release, which was inhibited by fenspiride. This study suggests a further mechanism that would promote anti-inflammatory and bronchodilator properties.

The findings in several thousand patients treated by 800 general practitioners have been reported [ ]. There were mild adverse reactions in 10% of the patients, but they were not thought to be specific to the drug (gastrointestinal, neurovegetative).

In 392 adults with acute respiratory tract infections, most of whom were considered to have a moderate symptom score that improved with 7 days of treatment with fenspiride, adverse reactions were classified as mild; only 20 of 392 patients stopped taking the drug [ ].