Differential effects of fexofenadine on arachidonic acid metabolism in cultured human monocytes

A dried yeast fermentate prevents and reduces inflammation in two separate experimental immune models

Diverse and significant benefits against cold/flu symptoms and seasonal allergies have been observed with a dried fermentate (DF) derived from Saccharomyces cerevisiae (EpiCor) in multiple published randomized trials. To determine if DF may influence other immune conditions, two separate animal studies were conducted. Study 1 examined the ability of DF to prevent or reduce inflammation when given orally for 14 days to rats prior to receiving 1% carrageenan (localized inflammation model). DF significantly (P < 0.05) reduced swelling at all time points (1, 2, 3, 6, 12, and 24 hours) versus the control. Edema severity and PGE2 levels were reduced by approximately 50% and 25% (P < 0.05), respectively. Study 2 examined the ability of DF to treat established inflammation induced by type-2 collagen in mice over 4 weeks (autoimmune arthritis model). Significantly reduced arthritis scores, antibody response to type-2 collagen, and interferon-gamma levels were observed compared to controls (all parameters P < 0.05). DF favorably impacts multiple acute and potentially chronic immunologic inflammatory control mechanisms and should be further tested in clinical trials.

Fexofenadine hydrochloride in the treatment of allergic disease: a review

Fexofenadine is a selective, non-sedating H1 receptor antagonist, marketed in the United States since 2000. The FDA approved an oral suspension in 2006, for the treatment of seasonal allergic rhinitis and chronic idiopathic urticaria in children. The tablet, capsule, and oral suspension are bioequivalent. Although fexofenadine does not use P450 CYP 3A4 it does interact with a number of drugs at P-glycoprotein and organic anion transporter polypeptides. The risk of toxicity from other drugs may increase with the administration of fexofenadine. Orange and grapefruit juices reduce the bioavailability of fexofenadine. Fexofenadine has been shown to have an impact on inflammatory mediators, other than histamine, such as decreasing the production of LTC₄, LTD₄, LTE₄, PGE₂, and PGF_2α; inhibiting cyclo-oxygenase 2, thromboxane; limiting iNOS generation of NO; decreasing cytokine levels (ICAM-1, ELAM-1, VCAM-1, RANTES, I-TAC, MDC, TARC, MMP-2, MMP-9, tryptase); and diminishing eosinophil adherence, chemotaxis, and opsonization of particles. These effects may provide benefit to some of the inflammatory responses of an acute allergic reaction and provide a basis for future development of H1 antagonists with stronger anti-inflammatory effects. These studies also support the contention that fexofenadine is effective for the treatment of allergic rhinits and chronic idiopathic urticaria.

New Evidence of H1-Receptor Independent COX-2 Inhibition by Fexofenadine HCl in vitro

BACKGROUND/AIMS

Fexofenadine HCl (FEX) has previously been shown to have anti-inflammatory properties in relieving nasal congestion in allergic rhinitis. The objective of this study was to further elucidate the mechanism of action behind the anti-inflammatory properties of FEX in addition to its H(1)-receptor antagonism.

METHODS

The effects of two antihistamines, FEX and loratadine (LOR), were investigated on cyclooxygenase (COX)-1 and -2 enzymes in vitro. FEX (10(-9)-10(-3) mol/l) and LOR (10(-9)-10(-4) mol/l) were incubated with arachidonic acid in a COX screening assay with either ovine COX-1 or COX-2 or human COX-2. COX-2 enzyme inhibitory activity for the antihistamines was compared with the known selective COX-2 inhibitor DuP-679.

RESULTS

High concentrations of FEX (10(-3) mol/l) significantly inhibited arachidonic acid-mediated ovine COX-1 activity, but low concentrations had no effect. Low concentrations of FEX (10(-8) mol/l) inhibited ovine COX-2 activity, and this inhibition decreased with increasing concentrations. The inhibition of COX-2 activity by FEX was similar to that seen with the selective COX-2 inhibitor, DuP-679. Conversely, LOR inhibited COX-1 activity at low concentrations (10(-8) mol/l), but had little inhibitory effect on COX-1 at high concentrations. LOR (10(-5) mol/l) markedly stimulated COX-2 activity.

CONCLUSION

FEX showed selective arachidonic acid-mediated COX-2 inhibitory enzyme activity, which differed markedly from the COX inhibitory enzyme activity of LOR. This selective COX-2 inhibitor activity by FEX may contribute to its anti-inflammatory properties in relieving nasal congestion in allergic rhinitis.