M K Church1. 1. Department of Dermatology and Allergy, Allergy Centre Charité, Charité-Universitätsmedizin Berlin, Berlin, Germany. mkc@southampton.ac.uk
Abstract
BACKGROUND: European guidelines recommend increasing H1-antihistamine doses up to fourfold in poorly responding patients with urticaria. OBJECTIVES: To assess the efficacy and tolerability of high-dose rupatadine (40 mg) against platelet-activating factor (PAF)- and histamine-induced flare responses in human skin and to verify its anti-PAF activity by assessing its inhibition of PAF-induced platelet aggregation in the blood of subjects receiving rupatadine 40 mg. METHODS: In the flare study, six male volunteers received a single dose of rupatadine 40 mg. Flares were induced before dosing and up to 96 h afterwards by intradermal PAF and histamine. In the ex vivo study, four male volunteers received an oral dose of rupatadine 40 mg and blood samples were taken 4 h afterwards. Platelet aggregation was assessed in platelet-rich plasma by incubation for 5 min with PAF. RESULTS: Rupatadine 40 mg reached maximal plasma levels of 15·1 ± 4·4 ng mL⁻¹)1 at 1 h and its metabolite, desloratadine, 5·2 ± 0·9 ng mL⁻¹)1 at 2 h. Neither was detectable at 12 h. Inhibition of histamine- and PAF-induced flares was significant within 2 h, maximal at 6 h (87·8 ± 3·1% and 87·1 ± 2·5% inhibition, respectively, P < 0·0001) and still statistically significant at 72 h. Rupatadine 40 mg inhibited PAF-induced platelet aggregation ex vivo by 82 ± 9% (P = 0·023). A single oral dose of rupatadine 40 mg was well tolerated with mild transient somnolence being reported. CONCLUSIONS: A single dose of rupatadine at four times the recommended dose is well tolerated, highly effective for up to 72 h against PAF- and histamine-induced dermal flares and has demonstrable PAF-receptor antagonism ex vivo.
BACKGROUND: European guidelines recommend increasing H1-antihistamine doses up to fourfold in poorly responding patients with urticaria. OBJECTIVES: To assess the efficacy and tolerability of high-dose rupatadine (40 mg) against platelet-activating factor (PAF)- and histamine-induced flare responses in human skin and to verify its anti-PAF activity by assessing its inhibition of PAF-induced platelet aggregation in the blood of subjects receiving rupatadine 40 mg. METHODS: In the flare study, six male volunteers received a single dose of rupatadine 40 mg. Flares were induced before dosing and up to 96 h afterwards by intradermal PAF and histamine. In the ex vivo study, four male volunteers received an oral dose of rupatadine 40 mg and blood samples were taken 4 h afterwards. Platelet aggregation was assessed in platelet-rich plasma by incubation for 5 min with PAF. RESULTS:Rupatadine 40 mg reached maximal plasma levels of 15·1 ± 4·4 ng mL⁻¹)1 at 1 h and its metabolite, desloratadine, 5·2 ± 0·9 ng mL⁻¹)1 at 2 h. Neither was detectable at 12 h. Inhibition of histamine- and PAF-induced flares was significant within 2 h, maximal at 6 h (87·8 ± 3·1% and 87·1 ± 2·5% inhibition, respectively, P < 0·0001) and still statistically significant at 72 h. Rupatadine 40 mg inhibited PAF-induced platelet aggregation ex vivo by 82 ± 9% (P = 0·023). A single oral dose of rupatadine 40 mg was well tolerated with mild transient somnolence being reported. CONCLUSIONS: A single dose of rupatadine at four times the recommended dose is well tolerated, highly effective for up to 72 h against PAF- and histamine-induced dermal flares and has demonstrable PAF-receptor antagonism ex vivo.
Authors: Reggie Bosma; Zhiyong Wang; Albert J Kooistra; Nick Bushby; Sebastiaan Kuhne; Jelle van den Bor; Michael J Waring; Chris de Graaf; Iwan J de Esch; Henry F Vischer; Robert J Sheppard; Maikel Wijtmans; Rob Leurs Journal: J Med Chem Date: 2019-07-05 Impact factor: 7.446