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Alsmadi MM, Abudaqqa AA, Idkaidek N, Qinna NA, Al-Ghazawi A. The Effect of Inflammatory Bowel Disease and Irritable Bowel Syndrome on Pravastatin Oral Bioavailability: In vivo and in silico evaluation using bottom-up wbPBPK modeling. AAPS PharmSciTech 2024; 25:86. [PMID: 38605192 DOI: 10.1208/s12249-024-02803-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/01/2024] [Indexed: 04/13/2024] Open
Abstract
The common disorders irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) can modify the drugs' pharmacokinetics via their induced pathophysiological changes. This work aimed to investigate the impact of these two diseases on pravastatin oral bioavailability. Rat models for IBS and IBD were used to experimentally test the effects of IBS and IBD on pravastatin pharmacokinetics. Then, the observations made in rats were extrapolated to humans using a mechanistic whole-body physiologically-based pharmacokinetic (wbPBPK) model. The rat in vivo studies done herein showed that IBS and IBD decreased serum albumin (> 11% for both), decreased PRV binding in plasma, and increased pravastatin absolute oral bioavailability (0.17 and 0.53 compared to 0.01) which increased plasma, muscle, and liver exposure. However, the wbPBPK model predicted muscle concentration was much lower than the pravastatin toxicity thresholds for myotoxicity and rhabdomyolysis. Overall, IBS and IBD can significantly increase pravastatin oral bioavailability which can be due to a combination of increased pravastatin intestinal permeability and decreased pravastatin gastric degradation resulting in higher exposure. This is the first study in the literature investigating the effects of IBS and IBD on pravastatin pharmacokinetics. The high interpatient variability in pravastatin concentrations as induced by IBD and IBS can be reduced by oral administration of pravastatin using enteric-coated tablets. Such disease (IBS and IBD)-drug interaction can have more drastic consequences for narrow therapeutic index drugs prone to gastric degradation, especially for drugs with low intestinal permeability.
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Affiliation(s)
- Motasem M Alsmadi
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan.
- Nanotechnology Institute, Jordan University of Science and Technology, Irbid, Jordan.
| | - Alla A Abudaqqa
- Faculty of Pharmacy and Biomedical Sciences, University of Petra, Amman, Jordan
| | - Nasir Idkaidek
- Faculty of Pharmacy and Biomedical Sciences, University of Petra, Amman, Jordan
| | - Nidal A Qinna
- Faculty of Pharmacy and Biomedical Sciences, University of Petra, Amman, Jordan
- University of Petra Pharmaceutical Center (UPPC), University of Petra, Amman, Jordan
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Wagner JB, Ruggiero M, Leeder JS, Hagenbuch B. Functional Consequences of Pravastatin Isomerization on OATP1B1-Mediated Transport. Drug Metab Dispos 2020; 48:1192-1198. [PMID: 32892153 PMCID: PMC7589943 DOI: 10.1124/dmd.120.000122] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/17/2020] [Indexed: 12/15/2022] Open
Abstract
Pravastatin acid (PVA) can be isomerized to its inactive metabolite 3'α-iso-pravastatin acid (3αPVA) under acidic pH conditions. Previous studies reported interindividual differences in circulating concentrations of PVA and 3αPVA. This study investigated the functional consequences of PVA isomerization on OATP1B1-mediated transport. We characterized 3αPVA inhibition of OATP1B1-mediated PVA uptake into human embryonic kidney 293 cells expressing the four different OATP1B1 proteins (*1a, *1b, *5, and *15). 3αPVA inhibited OATP1B1-mediated PVA uptake in all four OATP1B1 gene products but with lower IC50/Ki values for OATP1B1*5 and *15 than for the reference proteins (*1a and *1b). PVA and 3αPVA were transported by all four OATP1B1 proteins. Kinetic experiments revealed that maximal transport rates (Vmax values) for OATP1B1 variants *5 and *15 were lower than for *1a and *1b for both substrates. Apparent affinities for 3αPVA transport were similar for all four variants. However, the apparent affinity of OATP1B1*5 for 3αPVA was higher (lower Km value) than for PVA. These data confirm that PVA conversion to 3αPVA can have functional consequences on PVA uptake and impacts OATP1B1 variants more than the reference protein, thus highlighting another source variation that must be taken into consideration when optimizing the PVA dose-exposure relationship for patients. SIGNIFICANCE STATEMENT: 3'α-iso-pravastatin acid inhibits pravastatin uptake for all OATP1B1 protein types; however, the IC50 values were significantly lower in OATP1B1*5 and *15 transfected cells. This suggests that a lower concentration of 3'α-iso-pravastatin is needed to disrupt OATP1B1-mediated pravastatin uptake, secondary to decreased cell surface expression of functional OATP1B1 in variant-expressing cells. These data will refine previous pharmacokinetic models that are utilized to characterize pravastatin interindividual variability with an ultimate goal of maximizing efficacy at the lowest possible risk for toxicity.
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Affiliation(s)
- Jonathan B Wagner
- Ward Family Heart Center (J.B.W.) and Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation (J.B.W., J.S.L.), Children's Mercy, Kansas City, Missouri; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri (J.B.W., J.S.L.); and Department of Pharmacology, Toxicology, and Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas (M.R., B.H.)
| | - Melissa Ruggiero
- Ward Family Heart Center (J.B.W.) and Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation (J.B.W., J.S.L.), Children's Mercy, Kansas City, Missouri; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri (J.B.W., J.S.L.); and Department of Pharmacology, Toxicology, and Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas (M.R., B.H.)
| | - J Steven Leeder
- Ward Family Heart Center (J.B.W.) and Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation (J.B.W., J.S.L.), Children's Mercy, Kansas City, Missouri; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri (J.B.W., J.S.L.); and Department of Pharmacology, Toxicology, and Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas (M.R., B.H.)
| | - Bruno Hagenbuch
- Ward Family Heart Center (J.B.W.) and Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation (J.B.W., J.S.L.), Children's Mercy, Kansas City, Missouri; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri (J.B.W., J.S.L.); and Department of Pharmacology, Toxicology, and Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas (M.R., B.H.)
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Wagner JB, Abdel-Rahman S, Gaedigk R, Gaedigk A, Raghuveer G, Staggs VS, Kauffman R, Van Haandel L, Leeder JS. Impact of Genetic Variation on Pravastatin Systemic Exposure in Pediatric Hypercholesterolemia. Clin Pharmacol Ther 2019; 105:1501-1512. [PMID: 30549267 DOI: 10.1002/cpt.1330] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 11/20/2018] [Indexed: 11/07/2022]
Abstract
This study investigated the impact of SLCO1B1 genotype on pravastatin systemic exposure in children and adolescents with hypercholesterolemia. Participants (8-20 years) with at least one allelic variant of SLCO1B1 c.521T>C (521TC, n = 15; 521CC, n = 2) and wild-type controls (521TT, n = 15) completed a single oral dose pharmacokinetic study. Interindividual variability of pravastatin acid (PVA) exposure within SLCO1B1 genotype groups exceeded the approximately twofold difference in mean PVA exposure observed between SLCO1B1 genotype groups (P > 0.05, q > 0.10). The 3'α-iso-pravastatin acid and lactone isomer formation in the acidic environment of the stomach prior to absorption also was variable and affected PVA exposure in all genotype groups. The SLCO1B1 c.521 gene variant contributing to variability in systemic exposure to PVA in our pediatric cohort was comparable to previous studies in adults. However, other demographic and physicochemical factors seem to also contribute to interindividual variability in the dose-exposure relationship.
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Affiliation(s)
- Jonathan B Wagner
- Ward Family Heart Center, Children's Mercy, Kansas City, Missouri, USA
- Division of Clinical Pharmacology, Medical Toxicology and Therapeutic Innovation, Children's Mercy, Kansas City, Missouri, USA
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Susan Abdel-Rahman
- Division of Clinical Pharmacology, Medical Toxicology and Therapeutic Innovation, Children's Mercy, Kansas City, Missouri, USA
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Roger Gaedigk
- Division of Clinical Pharmacology, Medical Toxicology and Therapeutic Innovation, Children's Mercy, Kansas City, Missouri, USA
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Andrea Gaedigk
- Division of Clinical Pharmacology, Medical Toxicology and Therapeutic Innovation, Children's Mercy, Kansas City, Missouri, USA
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Geetha Raghuveer
- Ward Family Heart Center, Children's Mercy, Kansas City, Missouri, USA
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Vincent S Staggs
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
- Health Services & Outcomes Research, Children's Mercy, Kansas City, Missouri, USA
| | - Ralph Kauffman
- Division of Clinical Pharmacology, Medical Toxicology and Therapeutic Innovation, Children's Mercy, Kansas City, Missouri, USA
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Leon Van Haandel
- Division of Clinical Pharmacology, Medical Toxicology and Therapeutic Innovation, Children's Mercy, Kansas City, Missouri, USA
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
| | - J Steven Leeder
- Division of Clinical Pharmacology, Medical Toxicology and Therapeutic Innovation, Children's Mercy, Kansas City, Missouri, USA
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA
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Abstract
INTRODUCTION In pharmacotherapy, drugs are mostly taken orally to be absorbed systemically from the small intestine, and some drugs are known to have preferential absorption sites in the small intestine. It would therefore be valuable to know the absorption sites of orally administered drugs and the influencing factors. Areas covered:In this review, the author summarizes the reported absorption sites of orally administered drugs, as well as, influencing factors and experimental techniques. Information on the main absorption sites and influencing factors can help to develop ideal drug delivery systems and more effective pharmacotherapies. Expert opinion: Various factors including: the solubility, lipophilicity, luminal concentration, pKa value, transporter substrate specificity, transporter expression, luminal fluid pH, gastrointestinal transit time, and intestinal metabolism determine the site-dependent intestinal absorption. However, most of the dissolved fraction of orally administered drugs including substrates for ABC and SLC transporters, except for some weakly basic drugs with higher pKa values, are considered to be absorbed sequentially from the proximal small intestine. Securing the solubility and stability of drugs prior to reaching to the main absorption sites and appropriate delivery rates of drugs at absorption sites are important goals for achieving effective pharmacotherapy.
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Affiliation(s)
- Teruo Murakami
- a Laboratory of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmaceutical Sciences , Hiroshima International University , Hiroshima , Japan
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Wagner J, Abdel-Rahman SM. Pediatric Statin Administration: Navigating a Frontier with Limited Data. J Pediatr Pharmacol Ther 2016; 21:380-403. [PMID: 27877092 DOI: 10.5863/1551-6776-21.5.380] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Increasingly, children and adolescents with dyslipidemia qualify for pharmacologic intervention. As they are for adults, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) are the mainstay of pediatric dyslipidemia treatment when lifestyle modifications have failed. Despite the overall success of these drugs, the magnitude of variability in dose-exposure-response profiles contributes to adverse events and treatment failure. In children, the cause of treatment failures remains unclear. This review describes the updated guidelines for screening and management of pediatric dyslipidemia and statin disposition pathway to assist the provider in recognizing scenarios where alterations in dosage may be warranted to meet patients' specific needs.
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Affiliation(s)
- Jonathan Wagner
- Ward Family Heart Center, Children's Mercy Hospital, Kansas City, Missouri ; Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Hospital, Kansas City, Missouri ; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri
| | - Susan M Abdel-Rahman
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Hospital, Kansas City, Missouri ; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri
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6
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Momper JD, Tsunoda SM, Ma JD. Evaluation of Proposed In Vivo Probe Substrates and Inhibitors for Phenotyping Transporter Activity in Humans. J Clin Pharmacol 2016; 56 Suppl 7:S82-98. [DOI: 10.1002/jcph.736] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/23/2016] [Accepted: 03/07/2016] [Indexed: 01/10/2023]
Affiliation(s)
- Jeremiah D. Momper
- University of California, San Diego; Skaggs School of Pharmacy & Pharmaceutical Sciences; La Jolla CA USA
| | - Shirley M. Tsunoda
- University of California, San Diego; Skaggs School of Pharmacy & Pharmaceutical Sciences; La Jolla CA USA
| | - Joseph D. Ma
- University of California, San Diego; Skaggs School of Pharmacy & Pharmaceutical Sciences; La Jolla CA USA
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van Haandel L, Gibson KT, Leeder JS, Wagner JB. Quantification of pravastatin acid, lactone and isomers in human plasma by UHPLC-MS/MS and its application to a pediatric pharmacokinetic study. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1012-1013:169-77. [PMID: 26849185 DOI: 10.1016/j.jchromb.2016.01.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/18/2016] [Accepted: 01/21/2016] [Indexed: 12/25/2022]
Abstract
An ultra high pressure liquid chromatography-tandem mass spectrometric (UHPLC-MS/MS) method for the simultaneous quantitation of pravastatin and major metabolites, 3'α-hydroxy-pravastatin, pravalactone and 3'α-hydroxy-pravalactone, in human plasma has been developed and validated. Aliquots of (100μL) plasma in EDTA were diluted in pH 4.5 (0.1M buffer) to stabilize the analytes and subjected to hydrophilic lipophilic balance (HLB) solid phase extraction on 96 well μelution plates. Extracted samples were evaporated to dryness and reconstituted in pH 4.5 buffer. Chromatographic separation was performed on a Cortecs™ C18 column (2.1×100mm, 1.8μm), using gradient elution with a blend of acetonitrile and 10mM methylammonium acetate buffer (pH 4.5) at a flow rate of 0.4mL/min. Mass spectrometric detection was performed using multiple reaction monitoring (MRM) switching between positive/negative electrospay ionization (ESI). Pravastatin, 3'α-hydroxy-pravastatin, and internal standards [(2)H3]-pravastatin, and [(2)H3]-3'α-hydroxy-pravastatin were monitored in negative ESI mode at ion transitions m/z 423.2→321.1 and 426.2→321.1, respectively. Positive ESI mode was used for the detection of pravalactone, 3'α-hydroxy-pravalactone, and internal standards [(2)H3]-pravalactone, and [(2)H3]-3'α-hydroxy-pravalactone at ion transitions m/z 438.2→183.1 and 441.2→269.1 respectively. The method was linear for all analytes in the concentration range 0.5-200nM with intra- and inter-day precisions (as relative standard deviation) of ≤5.2% and accuracy (as relative error) of ≤8.0% at all quality control levels. The method was successfully applied to the investigation of pharmacokinetic properties of pravastatin and its metabolites in children after an oral dose of 20-40mg.
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Affiliation(s)
- Leon van Haandel
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Hospital, Kansas City, MO, United States; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108, United States.
| | - Kim T Gibson
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Hospital, Kansas City, MO, United States
| | - J Steven Leeder
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Hospital, Kansas City, MO, United States; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108, United States
| | - Jonathan B Wagner
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Hospital, Kansas City, MO, United States; Ward Family Heart Center, Children's Mercy Hospital, Kansas City, MO, United States; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108, United States
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8
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Tayel SA, El-Nabarawi MA, Tadros MI, Abd-Elsalam WH. Duodenum-triggered delivery of pravastatin sodium via enteric surface-coated nanovesicular spanlastic dispersions: Development, characterization and pharmacokinetic assessments. Int J Pharm 2015; 483:77-88. [PMID: 25666025 DOI: 10.1016/j.ijpharm.2015.02.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 01/15/2023]
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9
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Nyilasi I, Kocsubé S, Krizsán K, Galgóczy L, Papp T, Pesti M, Nagy K, Vágvölgyi C. Susceptibility of clinically important dermatophytes against statins and different statin-antifungal combinations. Med Mycol 2014; 52:140-8. [PMID: 24004389 DOI: 10.3109/13693786.2013.828160] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The investigation of the antifungal activities of drugs whose primary activities are not related to their antimicrobial potential is in the current forefront of research. Statin compounds, which are routinely used as cholesterol-lowering drugs, may also exert direct antimicrobial effects. In this study, the in vitro antifungal activities of various statins (lovastatin, simvastatin, fluvastatin, atorvastatin, rosuvastatin and pravastatin) were examined against one isolate each of four dermatophyte species (Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis and Microsporum gypseum). Basically, statins were effective in inhibiting all dermatophyte studied, but were particularly active against M. canis and T. mentagrophytes. Fluvastatin and simvastatin were active against all of the tested fungi causing a complete inhibition of their growth at very low concentrations (6.25-12.5 μg/ml). Lovastatin and rosuvastatin had inhibitory effects at higher concentrations (25-128 μg/ml), while atorvastatin and pravastatin proved the less effective. The in vitro interactions between statins and different antifungals (ketoconazole, itraconazole, fluconazole, amphotericin B, nystatin, griseofulvin, terbinafine and primycin) were also investigated using a standard chequerboard broth microdilution method. Synergetic interactions were observed in several cases, most of them were noticed when statins were combined with terbinafine and the different azoles. Some combinations were particularly active (ketoconazole-simvastatin or terbinafine-simvastatin), as they were found to exert synergistic effect against all of the investigated isolates. The other antifungals showed synergistic interactions with statins in only certain cases. These results suggest that statins exert substantial antifungal effects against dermatophyte fungi and they should be promising components in a combination therapy as they can act synergistically with a number of clinically used antifungal agents.
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10
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Intestinal drug transporters: an overview. Adv Drug Deliv Rev 2013; 65:1340-56. [PMID: 23041352 DOI: 10.1016/j.addr.2012.09.042] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 09/21/2012] [Accepted: 09/24/2012] [Indexed: 02/07/2023]
Abstract
The importance of drug transporters as one of the determinants of pharmacokinetics has become increasingly evident. While much research has been conducted focusing the role of drug transporters in the liver and kidney less is known about the importance of uptake and efflux transporters identified in the intestine. Over the past years the effects of intestinal transporters have been studied using in vivo models, in situ organ perfusions, in vitro tissue preparations and cell lines. This review aims to describe up to date findings regarding the importance of intestinal transporters on drug absorption and bioavailability, highlighting areas in need of further research. Wu and Benet proposed a Biopharmaceutics Drug Disposition Classification System (BDDCS) that allows the prediction of transporter effects on the drug disposition of orally administered drugs. This review also discusses BDDCS predictions with respect to the role of intestinal transporters and intestinal transporter-metabolizing enzyme interplay on oral drug pharmacokinetics.
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11
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Ide T, Sasaki T, Maeda K, Higuchi S, Sugiyama Y, Ieiri I. Quantitative Population Pharmacokinetic Analysis of Pravastatin Using an Enterohepatic Circulation Model Combined With Pharmacogenomic Information onSLCO1B1andABCC2Polymorphisms. J Clin Pharmacol 2013; 49:1309-17. [DOI: 10.1177/0091270009341960] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Aquilante CL, Kiser JJ, Anderson PL, Christians U, Kosmiski LA, Daily EB, Hoffman KL, Hopley CW, Predhomme JA, Schniedewind B, Sidhom MS. Influence of SLCO1B1 polymorphisms on the drug-drug interaction between darunavir/ritonavir and pravastatin. J Clin Pharmacol 2011; 52:1725-38. [PMID: 22174437 DOI: 10.1177/0091270011427907] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The authors investigated whether SLCO1B1 polymorphisms contribute to variability in pravastatin pharmacokinetics when pravastatin is administered alone versus with darunavir/ritonavir. HIV-negative healthy participants were prospectively enrolled on the basis of SLCO1B1 diplotype: group 1 (*1A/*1A, n = 9); group 2 (*1A/*1B, n = 10; or *1B/*1B, n = 2); and group 3 (*1A/*15, n = 1; *1B/*15, n = 5; or *1B/*17, n = 1). Participants received pravastatin (40 mg) daily on days 1 through 4, washout on days 5 through 11, darunavir/ritonavir (600/100 mg) twice daily on days 12 through 18, with pravastatin 40 mg added back on days 15 through 18. Pharmacokinetic studies were conducted on day 4 (pravastatin alone) and day 18 (pravastatin + darunavir/ritonavir). Pravastatin area under the plasma concentration-time curve (AUC(tau)) was 21% higher during administration with darunavir/ritonavir compared with pravastatin alone; however, this difference was not statistically significant (P = .11). Group 3 variants had 96% higher pravastatin AUC(tau) on day 4 and 113% higher pravastatin AUC(tau) on day 18 compared with group 1. The relative change in pravastatin pharmacokinetics was largest in group 3 but did not differ significantly between diplotype groups. In sum, the influence of SLCO1B1*15 and *17 haplotypes on pravastatin pharmacokinetics was maintained in the presence of darunavir/ritonavir. Because OATP1B1 inhibition would be expected to be greater in carriers of normal or high-functioning SLCO1B1 haplotypes, these findings suggest that darunavir/ritonavir is not a potent inhibitor of OATP1B1-mediated pravastatin transport in vivo.
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Affiliation(s)
- Christina L Aquilante
- PharmD, Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver, 12850 East Montview Blvd, Mail Stop C238, Room V20-4103, Aurora, CO 80045, USA.
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13
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Nyilasi I, Kocsubé S, Krizsán K, Galgóczy L, Pesti M, Papp T, Vágvölgyi C. In vitro synergistic interactions of the effects of various statins and azoles against some clinically important fungi. FEMS Microbiol Lett 2010; 307:175-84. [PMID: 20636975 DOI: 10.1111/j.1574-6968.2010.01972.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The treatment of opportunistic fungal infections is often difficult as the number of available antifungal agents is limited. Nowadays, there is increasing interest in the investigation of the antifungal activity of nonantifungal drugs, and in the development of efficient antifungal combination therapy. In this study, the in vitro interactions of the effects of various statins (lovastatin, simvastatin, fluvastatin, atorvastatin (ATO), rosuvastatin (ROS) and pravastatin) and various azole antifungals [miconazole, ketoconazole, itraconazole and fluconazole (FLU)] against different opportunistic pathogenic fungi were investigated using a standard chequerboard broth microdilution method. When the investigated strains were sensitive to both compounds of the combination, additive interactions were frequently noticed. Synergistic interactions were observed in many cases when a strain was sensitive only to the azole compound (as in certain combinations with ATO or ROS) or the statin compound (as in certain combinations with FLU). In many combinations with an additive effect, the concentrations of drugs needed for total growth inhibition could be decreased by several dilution steps. Similar interactions were observed when the variability of the within-species sensitivities to some selected drug combinations was investigated.
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Affiliation(s)
- Ildikó Nyilasi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
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14
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Sutton SC. The use of gastrointestinal intubation studies for controlled release development. Br J Clin Pharmacol 2010; 68:342-54. [PMID: 19740391 DOI: 10.1111/j.1365-2125.2009.03432.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIMS This review describes clinical results of gastrointestinal intubation studies of eight controlled release (CR) candidates under development during the 1990s and offers suggestions for determining why, when and how to conduct human intubation studies. METHODS Experience with the administration of the following eight compounds to various regions of the gastrointestinal tract is described: CJ-13,610, CP-195,543, CP-331,684, CP-409,092, CP-424,391, azithromycin, sertraline, and trovafloxacin. Also included are human pharmacokinetic studies with prototype CR dosage forms for CJ-13,610 and CP-424,391. RESULTS Intubation studies, while appearing invasive, are safe and not unpleasant procedures that have been found to be valuable in the development of CR formulations. CONCLUSIONS The following recommendations are made regarding intubation studies: (i) no intubation study is recommended for compounds with high permeability, since these compounds are likely to be well absorbed from the colon; (ii) compounds with moderate permeability may require an intubation study if the dog colon and in silico models predict a marginally acceptable CR concentration-time profile; (iii) use a dose that approximates 1 h of the intended CR delivery rate; (iv) use the smallest volume possible; (v) define and record tubing placement; (vi) use a thermodynamically stable solution or/and suspension.
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Affiliation(s)
- Steven C Sutton
- College of Pharmacy, University of New England, 716 Stevens Avenue, Portland, ME 04103, USA.
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15
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Kivistö KT, Niemi M. Influence of Drug Transporter Polymorphisms on Pravastatin Pharmacokinetics in Humans. Pharm Res 2006; 24:239-47. [PMID: 17177112 DOI: 10.1007/s11095-006-9159-2] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Accepted: 08/31/2006] [Indexed: 01/11/2023]
Abstract
The role of drug transporters in pravastatin disposition is underlined by the fact that pravastatin does not undergo significant cytochrome P-450 (CYP)-mediated biotransformation. The organic anion transporting polypeptide 1B1 (OATP1B1), encoded by SLCO1B1, and multidrug resistance-associated protein 2 [MRP2 (ABCC2)], are thought to be the major transporters involved in the pharmacokinetics of pravastatin in humans. Other transporters that may play a role include OATP2B1, organic anion transporter 3 (OAT3), bile salt export pump (BSEP), and the breast cancer resistance protein (BCRP). OATP1B1 and MRP2 mediate the hepatic uptake and biliary excretion of pravastatin, respectively. The SLCO1B1 and ABCC2 polymorphisms probably contribute to the high interindividual variability in pravastatin disposition. Recent small studies have characterized the impact of the SLCO1B1 polymorphism on pravastatin in humans, and especially the c.521T>C single-nucleotide polymorphism (SNP) seems to be an important determinant of pravastatin pharmacokinetics. Pravastatin plasma concentrations may be up to 100% higher in subjects carrying the c.521C variant, as found in the *5, *15, *16, and *17 haplotypes, reflecting diminished OATP1B1-mediated uptake into the major site of pravastatin elimination, the liver. The SLCO1B1 polymorphism seems to have a similar impact on the pharmacokinetics of single- and multiple-dose pravastatin. Overall, 2-5% of individuals in various populations may be expected to show markedly elevated plasma pravastatin concentrations due to the SLCO1B1 polymorphism. Of note, the impact of the SLCO1B1 polymorphism on statins may be dependent on ethnicity. Although individuals with a diminished hepatic uptake of pravastatin might be expected to show reduced cholesterol-lowering efficacy due to lower intracellular pravastatin concentrations, there is preliminary evidence to suggest that the SLCO1B1 polymorphism is not a major determinant of non-response to pravastatin. The possible consequences of drug transporter polymorphisms, especially the SLCO1B1 and ABCC2 polymorphisms, for the lipid-lowering efficacy and tolerability of pravastatin in various ethnic groups warrant further study.
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Affiliation(s)
- Kari T Kivistö
- Department of Pharmacological Sciences, Medical School, University of Tampere, Tampere 33014, Finland.
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Niemi M, Schaeffeler E, Lang T, Fromm MF, Neuvonen M, Kyrklund C, Backman JT, Kerb R, Schwab M, Neuvonen PJ, Eichelbaum M, Kivistö KT. High plasma pravastatin concentrations are associated with single nucleotide polymorphisms and haplotypes of organic anion transporting polypeptide-C (OATP-C, SLCO1B1). ACTA ACUST UNITED AC 2005; 14:429-40. [PMID: 15226675 DOI: 10.1097/01.fpc.0000114750.08559.32] [Citation(s) in RCA: 300] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This study aimed to characterize possible relationships between polymorphisms in the drug transporter genes organic anion transporting polypeptide-C (OATP-C, SLCO1B1), OATP-B (SLCO2B1), multidrug resistance-associated protein 2 (MRP2, ABCC2) and multidrug resistance transporter (MDR1, ABCB1) and the pharmacokinetics of pravastatin. We studied 41 healthy Caucasian volunteers who had previously participated in pharmacokinetic studies with pravastatin. Six volunteers had a very high pravastatin AUC value and were defined as outliers according to statistical criteria. The OATP-C gene was sequenced completely in all subjects, and they were also genotyped for selected single nucleotide polymorphisms (SNP) in the OATP-B, MDR1 and MRP2 genes. Of the six outliers, five were heterozygous for the OATP-C 521T>C (Val174Ala) SNP (allele frequency 42%) and three were heterozygous for a new SNP in the promoter region of OATP-C (-11187G>A, allele frequency 25%). Among the remaining 35 subjects, two were homozygous and six were heterozygous carriers of the 521T>C SNP (allele frequency 14%, P = 0.0384 versus outliers) and three were heterozygous carriers of the -11187G>A SNP (allele frequency 4%, P = 0.0380 versus outliers). In subjects with the -11187GA or 521TC genotype, the mean pravastatin AUC0-12 was 98% (P = 0.0061) or 106% (P = 0.0034) higher, respectively, compared to subjects with the reference genotype. These results were substantiated by haplotype analysis. In heterozygous carriers of *15B (containing the 388A>G and 521T>C variants), the mean pravastatin AUC0-12 was 93% (P = 0.024) higher compared to non-carriers and, in heterozygous carriers of *17 (containing the -11187G>A, 388A>G and 521T>C variants), it was 130% (P = 0.0053) higher compared to non-carriers. No significant associations were found between OATP-B, MRP2 or MDR1 polymorphisms and the pharmacokinetics of pravastatin. These results suggest that haplotypes are more informative in predicting the OATP-C phenotype than single SNPs.
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Affiliation(s)
- Mikko Niemi
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
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Wiersma HE, Wiegman A, Koopmans RP, Bakker HD, Kastelein JJP, van Boxtel CJ. Steady-State Pharmacokinetics of Pravastatin in Children with Familial Hypercholesterolaemia. Clin Drug Investig 2004; 24:113-20. [PMID: 17516697 DOI: 10.2165/00044011-200424020-00006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
OBJECTIVE To determine pharmacokinetic data for pravastatin in children, since current data are insufficient in this age group. SUBJECTS AND METHODS A 2-week, multiple-dose, steady-state pharmacokinetic study was carried out with pravastatin 20mg daily in 24 children with familial hypercholesterolaemia (aged 8-16 years; 12 prepubertal, 12 pubertal). A plasma concentration-time curve was performed on day 14. Pharmacokinetic curves for each individual were constructed using nonparametric methods, yielding area under the plasma concentration-time curve (AUC), maximum plasma concentration (C(max)) and half-life (t((1/2))). Clearance values and volumes of distribution were calculated from these parameters. Cholesterol lowering was observed on day 14 and 6 weeks after the start of pravastatin. RESULTS The C(max) in prepubertal (group A) children (52.1 +/- 27.0 mug/L [mean +/- SD]) differed, although not significantly (p = 0.09, unpaired two-tailed t-test), from the C(max) in adolescents (group B) [31.7 +/- 29.2 mug/L]. There was a moderate negative correlation between C(max) and age (Spearman correlation r = -0.42; p = 0.04). The AUC in prepubertal children (91.3 +/- 39.7 mug . h/L) did not differ significantly from the AUC in adolescents (69.3 +/- 57.0 mug . h/L). The t((1/2)) was the same for the two groups: 2.5 +/- 1.1h. Clearance values (CL/f) varied widely between the two groups (group A: 4.3 +/- 1.8 L/min; group B: 11.0 +/- 11.9 L/min; p = 0.08). A moderate positive correlation was found between clearance and age (Spearman correlation r = 0.36; p = 0.09). A large variation was found in the volumes of distribution within the two groups (group A: 31.2 mL/kg [SD 26.7], group B:37.0 mL/kg [SD 29.6]; p = 0.12). A very weak positive correlation was found between age and volume of distribution (Spearman correlation r = 0.11; p = 0.61). A 27% low-density lipoprotein-cholesterol reduction from baseline was achieved at day 14. CONCLUSIONS Body surface area and gender did not influence the pharmacokinetics of pravastatin in children aged 8-16 years. On the basis of our findings there are no reasons to use pravastatin at a dosage according to bodyweight or to use different dosage regimens from those in adults. However, for prepubertal children half the advised starting dose for adults may be sufficient.
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Affiliation(s)
- Heleen E Wiersma
- Emma Children's Hospital/Academic Medical Centre, Amsterdam, The NetherlandsDepartment of Clinical Pharmacology and Pharmacotherapy, Academic Medical Centre, Amsterdam, The Netherlands
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Kobayashi D, Nozawa T, Imai K, Nezu JI, Tsuji A, Tamai I. Involvement of human organic anion transporting polypeptide OATP-B (SLC21A9) in pH-dependent transport across intestinal apical membrane. J Pharmacol Exp Ther 2003; 306:703-8. [PMID: 12724351 DOI: 10.1124/jpet.103.051300] [Citation(s) in RCA: 338] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Some organic anions are absorbed from the gastrointestinal tract through carrier-mediated transport mechanism(s), which may include proton-coupled transport, anion exchange transport, and others. However, the molecular identity of the organic anion transporters localized at the apical membrane of human intestinal epithelial cells has not been clearly demonstrated. In the present study, we focused on human organic anion transporting polypeptide OATP-B and examined its subcellular localization and functionality in the small intestine. Localization of OATP-B was determined by immunohistochemical analysis. Transport properties of estrone-3-sulfate and the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor pravastatin by OATP-B-transfected human embryonic kidney 293 cells were measured. OATP-B was immunohistochemically localized at the apical membrane of intestinal epithelial cells in humans. Uptake of [3H]estrone-3-sulfate and [14C]pravastatin by OATP-B at pH 5.5 was higher than that at pH 7.4. [3H]Estrone-3-sulfate transport was decreased by pravastatin, aromatic anion compounds, and the anion exchange inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, but not by small anionic compounds, such as lactic acid and acetic acid. The inhibitory effect of pravastatin on the uptake of [3H]estrone-3-sulfate was concentration-dependent, and the IC50 value was 5.5 mM. The results suggested that OATP-B mediates absorption of anionic compounds and its activity may be optimum at the acidic surface microclimate pH of the small intestine. Accordingly, OATP-B plays a role in the absorption of anionic compounds across the apical membrane of human intestinal epithelial cells, although it cannot be decisively concluded that pH-dependent absorption of pravastatin is determined by OATP-B alone.
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Affiliation(s)
- Daisuke Kobayashi
- Department of Molecular Biopharmaceutics, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Tokyo, Japan
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Abstract
Pravastatin, one of the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) widely used in the management of hypercholesterolaemia, has unique pharmacokinetic characteristics among the members of this class. Many in vivo and in vitro human and animal studies suggest that active transport mechanisms are involved in the pharmacokinetics of pravastatin. The oral bioavailability of pravastatin is low because of incomplete absorption and a first-pass effect. The drug is rapidly absorbed from the upper part of the small intestine, probably via proton-coupled carrier-mediated transport, and then taken up by the liver by a sodium-independent bile acid transporter. About half of the pravastatin that reaches the liver via the portal vein is extracted by the liver, and this hepatic extraction is mainly attributed to biliary excretion which is performed by a primary active transport mechanism. The major metabolites are produced by chemical degradation in the stomach rather than by cytochrome P450-dependent metabolism in the liver. The intact drug and its metabolites are cleared through both hepatic and renal routes, and tubular secretion is a predominant mechanism in renal excretion. The dual routes of pravastatin elimination reduce the need for dosage adjustment if the function of either the liver or kidney is impaired, and also reduce the possibility of drug interactions compared with other statins. which are largely eliminated by metabolism. The lower protein binding than other statins weakens the tendency for displacement of highly protein-bound drugs. Although all statins show a hepatoselective disposition, the mechanism for pravastatin is different from that of the others. There is high uptake of pravastatin by the liver via an active transport mechanism, but not by other tissues because of its hydrophilicity, whereas the disposition characteristics of other statins result from high hepatic extraction because of high lipophilicity. These pharmacokinetic properties of pravastatin may be the result of the drug being given in the pharmacologically active open hydroxy acid form and the fact that its hydrophilicity is markedly higher than that of other statins. The nature of the pravastatin transporters, particularly in humans, remains unknown at present. Further mechanistic studies are required to establish the pharmacokinetic-pharmacodynamic relationships of pravastatin and to provide the optimal therapeutic efficacy for various types of patients with hypercholesterolaemia.
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Affiliation(s)
- T Hatanaka
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
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Heerey A, Barry M, Ryan M, Kelly A. The potential for drug interactions with statin therapy in Ireland. Ir J Med Sci 2000; 169:176-9. [PMID: 11272871 DOI: 10.1007/bf03167690] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Seven percent of acute hospital admissions result from adverse drug reactions, of which 25% are due to drug interactions. Adverse effects of statin drugs occur in 3% of patients, mainly due to co-prescribing with other lipid-lowering agents or agents that alter their metabolism. AIM The aim of this study was to investigate co-prescribing of the frequently-used statin medications with interacting drugs. METHODS Data from the General Medical Services (GMS) scheme of the Eastern Health Board from January to December 1998 were used in this study. Using the coding index for statins, co-prescribing was identified when concomitant medications were administered under the same GMS claim number. RESULTS Of 7,602 patients prescribed statins, co-prescribing of simvastatin, atorvastatin and fluvastatin with competing substrates or inhibitors of their metabolism occurred in 32, 26 and 13.4% of prescriptions issued. Thirty-four per cent of patients on simvastatin, 28% on atorvastatin and 16% on fluvastatin were prescribed medications with drug interaction potential. CONCLUSION Co-prescribing of statins with competing substrates or inhibitors of their metabolism occurred in up to one-third of prescriptions issued. When statins are co-prescribed with recognised inhibitors of drug metabolism, pravastatin, which does not undergo significant hepatic metabolism, is the statin of choice.
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Affiliation(s)
- A Heerey
- Department of Pharmacology and Therapeutics, University of Dublin, Trinity College, Dublin, Ireland
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Christians U, Jacobsen W, Floren LC. Metabolism and drug interactions of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors in transplant patients: are the statins mechanistically similar? Pharmacol Ther 1998; 80:1-34. [PMID: 9804052 DOI: 10.1016/s0163-7258(98)00016-3] [Citation(s) in RCA: 167] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.88) inhibitors are the most effective drugs to lower cholesterol in transplant patients. However, immunosuppressants and several other drugs used after organ transplantation are cytochrome P4503A (CYP3A, EC 1.14.14.1) substrates. Pharmacokinetic interaction with some of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, specifically lovastatin and simvastatin, leads to an increased incidence of muscle skeletal toxicity in transplant patients. It is our objective to review the role of drug metabolism and drug interactions of lovastatin, simvastatin, pravastatin, fluvastatin, atorvastatin, and cerivastatin. In the treatment of transplant patients, from a drug interaction perspective, pravastatin, which is not significantly metabolized by CYP enzymes, and fluvastatin, presumably a CYP2C9 substrate, compare favorably with the other statins for which the major metabolic pathways are catalyzed by CYP3A.
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Affiliation(s)
- U Christians
- Department of Biopharmaceutical Sciences, School of Pharmacy, University of California at San Francisco, 94143-0446, USA
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Ito MK. Effects of extensive and poor gastrointestinal metabolism on the pharmacodynamics of pravastatin. J Clin Pharmacol 1998; 38:331-6. [PMID: 9590460 DOI: 10.1002/j.1552-4604.1998.tb04432.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The enhanced nonenzymatic isomerization of pravastatin to SQ 31,906, a relatively inactive metabolite, has been demonstrated to occur on exposure to gastric acidity in humans. However, the effect of gastric metabolism on the pharmacodynamics of pravastatin has not been studied. In addition, it was hypothesized that some individuals may be more extensive gastric metabolizers than others. Sixteen men received 4 weeks of oral therapy with pravastatin 10 mg after a 6-week drug washout diet run-in period. Pharmacokinetic and pharmacodynamic parameters were determined after 8 hours of serum sampling on the final day of therapy. Patients with a metabolic ratio for area under the concentration-time curve (AUC0-8 of pravastatin/AUC0-8 of SQ 31,906) of less than 1.6 had a significantly lower reduction in total and low-density lipoprotein (LDL) cholesterol compared with those with a ratio > 1.6. An enteric formulation of pravastatin should increase the bioavailability of pravastatin and enhanced lipid-lowering efficacy.
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Affiliation(s)
- M K Ito
- Cardiovascular Pharmacodynamics Laboratory at the Veterans Administration Health Care Systems, San Diego, California 92161, USA
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Lennernäs H, Fager G. Pharmacodynamics and pharmacokinetics of the HMG-CoA reductase inhibitors. Similarities and differences. Clin Pharmacokinet 1997; 32:403-25. [PMID: 9160173 DOI: 10.2165/00003088-199732050-00005] [Citation(s) in RCA: 376] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Hypercholesterolaemia plays a crucial role in the development of atherosclerotic diseases in general and coronary heart disease in particular. The risk of progression of the atherosclerotic process to coronary heart disease increases progressively with increasing levels of total serum cholesterol or low density lipoprotein (LDL) cholesterol at both the individual and the population level. The statins are reversible inhibitors of the microsomal enzyme HMG-CoA reductase, which converts HMG-CoA to mevalonate. This is an early rate-limiting step in cholesterol biosynthesis. Inhibition of HMG-CoA reductase by statins decreases intracellular cholesterol biosynthesis, which then leads to transcriptionally upregulated production of microsomal HMG-CoA reductase and cell surface LDL receptors. Subsequently, additional cholesterol is provided to the cell by de novo synthesis and by receptor-mediated uptake of LDL-cholesterol from the blood. This resets intracellular cholesterol homeostasis in extrahepatic tissues, but has little effect on the overall cholesterol balance. There are no simple methods to investigate the concentration-dependent inhibition of HMG-CoA reductase in human pharmacodynamic studies. The main clinical variable is plasma LDL-cholesterol, which takes 4 to 6 weeks to show a reduction after the start of statin treatment. Consequently, a dose-effect rather than a concentration-effect relationship is more appropriate to use in describing the pharmacodynamics. Fluvastatin, lovastatin, pravastatin and simvastatin have similar pharmacodynamic properties; all can reduce LDL-cholesterol by 20 to 35%, a reduction which has been shown to achieve decreases of 30 to 35% in major cardiovascular outcomes. Simvastatin has this effect at doses of about half those of the other 3 statins. The liver is the target organ for the statins, since it is the major site of cholesterol biosynthesis, lipoprotein production and LDL catabolism. However, cholesterol biosynthesis in extrahepatic tissues is necessary for normal cell function. The adverse effects of HMG-reductase inhibitors during long term treatment may depend in part upon the degree to which they act in extrahepatic tissues. Therefore, pharmacokinetic factors such as hepatic extraction and systemic exposure to active compound(s) may be clinically important when comparing the statins. Different degrees of liver selectivity have been claimed for the HMG-CoA reductase inhibitors. However, the literature contains confusing data concerning the degree of liver versus tissue selectivity. Human pharmacokinetic data are poor and incomplete, especially for lovastatin and simvastatin, and it is clear that any conclusion on tissue selectivity is dependent upon the choice of experimental model. However, the drugs do differ in some important aspects concerning the degree of metabolism and the number of active and inactive metabolites. The rather extensive metabolism by different cytochrome P450 isoforms also makes it difficult to characterise these drugs regarding tissue selectivity unless all metabolites are well characterised. The effective elimination half-lives of the hydroxy acid forms of the 4 statins are 0.7 to 3.0 hours. Protein binding is similar (> 90%) for fluvastatin, lovastatin and simvastatin, but it is only 50% for pravastatin. The best characterised statins from a clinical pharmacokinetic standpoint are fluvastatin and pravastatin. The major difference between these 2 compounds is the higher liver extraction of fluvastatin during the absorption phase compared with pravastatin (67 versus 45%, respectively, in the same dose range). Estimates of liver extraction in humans for lovastatin and simvastatin are poorly reported, which makes a direct comparison difficult.
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Affiliation(s)
- H Lennernäs
- Department of Pharmacy, Uppsala University, Sweden.
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Desager JP, Horsmans Y. Clinical pharmacokinetics of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors. Clin Pharmacokinet 1996; 31:348-71. [PMID: 9118584 DOI: 10.2165/00003088-199631050-00003] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is the key enzyme of cholesterol synthesis. HMG-CoA reductase inhibitors are potent reversible inhibitors of this enzyme, which act by competing for the substrate HMG-CoA. This review is mainly devoted to the 4 main HMG-CoA reductase inhibitors used today: lovastatin, simvastatin, pravastatin and fluvastatin. Depending upon the dosage, these drugs are able to reduce plasma cholesterol levels by more than 40%. After absorption, each undergoes extensive hepatic first-pass metabolism. Up to 5 primary metabolites are formed, some of which are active inhibitors. The elimination half-lives vary from 0.5 to 3.5 hours and excretion is mainly via the faeces. A limited number of drug interactions has been reported. Increases in liver enzymes and muscle creatine kinase activity are among the most severe adverse effects. These powerful drugs should be reserved for patients with high plasma cholesterol levels and/or those with cardiovascular disease. New therapeutic approaches to atherosclerosis are currently under investigation. HMG-CoA reductase inhibitors are the cornerstone of this research.
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Affiliation(s)
- J P Desager
- Departement de Médecine Interne, Université Catholique de Louvain, Brussels, Belgium
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