title: Evaluation of appropriate blood level in continuous intravenous infusion from trough concentrations after oral administration based on area under trough level in tacrolimus and cyclosporine therapy.
abstract: The target blood concentrations of tacrolimus (TAC) and cyclosporine (CYA) during continuous intravenous infusion (C(ss)) have been determined based on clinical experience. However, it is desirable that C(ss) should be set so that the AUC after intravenous infusion is equal to the AUC after oral administration (AUC(po)). Accordingly, we performed 12-hour monitoring of blood concentrations to calculate C(ss) from the blood trough levels (C(TL)) on 15 kidney recipients administered TAC and 12 recipients administered CYA (Neoral). We used an area under the trough level (AUTL) as a new pharmacokinetic parameter. The C(ss) was evaluated from C(TL), AUC(po), and AUTL was calculated to be C(ss) = C(TL) x (AUC(po)/AUTL). In addition, AUTL/AUC(po) ratio and blood peak/trough level ratio (C(max)/C(min)) were examined to compare pharmacokinetics of TAC and CYA. The formula for TAC was C(ss) = C(TL) x 1.40 and that for CYA, C(ss) = C(TL) x 2.55. The calculated target C(ss) of TAC was 1.40 times that of C(TL), which was similar to the present clinical C(TL). In contrast, the calculated target C(ss) of CYA was 2.55 times the C(TL), and therefore an extremely high C(ss) was necessary to obtain a sufficient AUC that will be available after oral administration. Consequently, intravenous administration of CYA twice a day was considered to be more appropriate to obtain sufficient CYA pharmacokinetics, rather than a continuous intravenous administration. We conclude that the formula, C(ss) = C(TL) x (AUC(po)/AUTL) was useful to calculate the target blood concentration of calcineurin inhibitors when changing from continuous intravenous infusion to oral administration of these drugs.
authors.affiliation: The 5TH Department of Surgery, Hachioji Medical Center, Tokyo Medical University, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: H
authors.initials: H
authors.lastname: Takeuchi
authors.forename: K
authors.initials: K
authors.lastname: Okuyama
authors.forename: T
authors.initials: T
authors.lastname: Akashi
authors.forename: Y
authors.initials: Y
authors.lastname: Jojima
authors.forename: O
authors.initials: O
authors.lastname: Konno
authors.forename: I
authors.initials: I
authors.lastname: Akashi
authors.forename: K
authors.initials: K
authors.lastname: Hama
authors.forename: T
authors.initials: T
authors.lastname: Iwahori
authors.forename: T
authors.initials: T
authors.lastname: Ashizawa
authors.forename: T
authors.initials: T
authors.lastname: Hirano
authors.forename: K
authors.initials: K
authors.lastname: Oka
authors.forename: N
authors.initials: N
authors.lastname: Matsuno
authors.forename: T
authors.initials: T
authors.lastname: Nagao
mesh_terms: D000284:Administration, Oral; D019540:Area Under Curve; D016572:Cyclosporine / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D007262:Infusions, Intravenous; D016030:Kidney Transplantation / Q000276:immunology / Q000502:physiology*; D016559:Tacrolimus / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D016559:Tacrolimus