title: Enhanced absorption of pour-on ivermectin formulation in rats by co-administration of the multidrug-resistant-reversing agent verapamil.
abstract: The effect of verapamil, a multidrug-resistance (Mdr)-reversing agent on the absorption of a pour-on formulation of ivermectin was evaluated in rats. Absorption of ivermectin was effectively enhanced (40%) by the presence of verapamil, suggesting that absorption of ivermectin involves Mdr-P-glycoprotein and that verapamil should act as a competitive inhibitor for the transport and extrusion of ivermectin by P-glycoprotein. This hypothesis is consistent with other studies describing verapamil as a blocking agent of P-glycoprotein involved in the efflux of ivermectin in a resistant strain of Haemonchus contortus.
authors.affiliation: Laboratoire de Pharmacologie-Toxicologie, INRA, Toulouse, France. malviner@toulouse.inra.fr
authors.forename: M
authors.initials: M
authors.lastname: Alvinerie
authors.forename: J
authors.initials: J
authors.lastname: Dupuy
authors.forename: C
authors.initials: C
authors.lastname: Eeckhoutte
authors.forename: J F
authors.initials: JF
authors.lastname: Sutra
mesh_terms: D000042:Absorption; D000279:Administration, Cutaneous; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D018432:Drug Resistance, Multiple; D007559:Ivermectin / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012869:Skin Absorption; D014700:Verapamil / Q000008:administration & dosage*
chemical_list: D000871:Anthelmintics; D007559:Ivermectin; D014700:Verapamil