101
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Abstract
Fluvastatin, the first fully synthetic HMG-CoA reductase inhibitor, has been shown to reduce cholesterol in patients with hyperlipidaemia, to prevent subsequent coronary events in patients with established coronary heart disease, and to alter endothelial function and plaque stability in animal models. Fluvastatin is relatively hydrophilic, compared with the semisynthetic HMG-CoA reductase inhibitors, and, therefore, it is extensively absorbed from the gastrointestinal tract. After absorption, it is nearly completely extracted and metabolised in the liver to 2 hydroxylated metabolites and an N-desisopropyl metabolite, which are excreted in the bile. Approximately 95% of a dose is recovered in the faeces, with 60% of a dose recovered as the 3 metabolites. The 6-hydroxy and N-desisopropyl fluvastatin metabolites are exclusively generated by cytochrome P450 (CYP) 2C9 and do not accumulate in the blood. CYP2C9, CYP3A4, CYP2C8 and CYP2D6 form the 5-hydroxy fluvastatin metabolite. Because of its hydrophilic nature and extensive plasma protein binding, fluvastatin has a small volume of distribution with minimal concentrations in extrahepatic tissues. The pharmacokinetics of fluvastatin are not influenced by renal function, due to its extensive metabolism and biliary excretion; limited data in patients with cirrhosis suggest a 30% reduction in oral clearance. Age and gender do not appear to affect the disposition of fluvastatin. CYP3A4 inhibitors (erythromycin, ketoconazole and itraconazole) have no effect on fluvastatin pharmacokinetics, in contrast to other HMG-CoA reductase inhibitors which are primarily metabolised by CYP3A and are subject to potential drug interactions with CYP3A inhibitors. Coadministration of fluvastatin with gastrointestinal agents such as cholestyramine, and gastric acid regulating agents (H2 receptor antagonists and proton pump inhibitors), significantly alters fluvastatin disposition by decreasing and increasing bioavailability, respectively. The nonspecific CYP inducer rifampicin (rifampin) significantly increases fluvastatin oral clearance. In addition to being a CYP2C9 substrate, fluvastatin demonstrates inhibitory effects on this isoenzyme in vitro and in vivo. In human liver microsomes, fluvastatin significantly inhibits the hydroxylation of 2 CYP2C9 substrates, tolbutamide and diclofenac. The oral clearances of the CYP2C9 substrates diclofenac, tolbutamide, glibenclamide (glyburide) and losartan are reduced by 15 to 25% when coadministered with fluvastatin. These alterations have not been shown to be clinically significant. There are inadequate data evaluating the potential interaction of fluvastatin with warfarin and phenytoin, 2 CYP2C9 substrates with a narrow therapeutic index, and caution is recommended when using fluvastatin with these agents. Fluvastatin does not appear to have a significant effect on other CYP isoenzymes or P-glycoprotein-mediated transport in vivo.
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Affiliation(s)
- C D Scripture
- Division of Pharmacotherapy, School of Pharmacy, University of North Carolina, Chapel Hill 27599-7360, USA
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102
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Eberlein M, Heusinger-Ribeiro J, Goppelt-Struebe M. Rho-dependent inhibition of the induction of connective tissue growth factor (CTGF) by HMG CoA reductase inhibitors (statins). Br J Pharmacol 2001; 133:1172-80. [PMID: 11487529 PMCID: PMC1572879 DOI: 10.1038/sj.bjp.0704173] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
It was supposed that inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG CoA) reductase (statins) might inhibit the expression of the fibrosis-related factor CTGF (connective tissue growth factor) by interfering with the isoprenylation of Rho proteins. The human renal fibroblast cell line TK173 was used as an in vitro model system to study the statin-mediated modulation of the structure of the actin cytoskeleton and of the expression of CTGF mRNA. Incubation of the cells with simvastatin or lovastatin time-dependently and reversibly changed cell morphology and the actin cytoskeleton with maximal effects observed after about 18 h. Within the same time period, statins reduced the basal expression of CTGF and interfered with CTGF induction by lysophosphatidic acid (LPA) or transforming growth factor beta. Simvastatin and lovastatin proved to be much more potent than pravastatin (IC(50) 1 - 3 microM compared to 500 microM). The inhibition of CTGF expression was prevented when the cells were incubated with mevalonate or geranylgeranylpyrophosphate (GGPP) but not by farnesylpyrophosphate (FPP). Specific inhibition of geranylgeranyltransferase-I by GTI-286 inhibited LPA-mediated CTGF expression whereas an inhibitor of farnesyltransferases FTI-276 was ineffective. Simvastatin reduced the binding of the small GTPase RhoA to cellular membranes. The effect was prevented by mevalonate and GGPP, but not FPP. These data are in agreement with the hypothesis that interference of statins with the expression of CTGF mRNA is primarily due to interference with the isoprenylation of RhoA, in line with previous studies, which have shown that RhoA is an essential mediator of CTGF induction. The direct interference of statins with the synthesis of CTGF, a protein functionally related to the development of fibrosis, may thus be a novel mechanism underlying the beneficial effects of statins observed in renal diseases.
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Affiliation(s)
- Michael Eberlein
- Medizinische Klinik IV, Universität Erlangen-Nürnberg, Loschgestrasse 8, D-91054 Erlangen, Germany
| | | | - Margarete Goppelt-Struebe
- Medizinische Klinik IV, Universität Erlangen-Nürnberg, Loschgestrasse 8, D-91054 Erlangen, Germany
- Author for correspondence:
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103
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Worz CR, Bottorff M. The role of cytochrome P450-mediated drug-drug interactions in determining the safety of statins. Expert Opin Pharmacother 2001; 2:1119-27. [PMID: 11583063 DOI: 10.1517/14656566.2.7.1119] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The objectives of this review are to discuss the role of cytochrome P450 (CYP450) isoforms in drug metabolism, to explain differences in metabolism among the HMG-CoA reductase inhibitors (HMGs, statins), to review drug-drug and drug-food interaction studies dealing with the HMGs, to present case reports dealing with HMG-related myopathy, to discuss major clinical implications of these case reports and to express an opinion of use of HMGs in clinical practice.
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Affiliation(s)
- C R Worz
- Department of Pharmacy, University of Cincinnati, Ohio, USA.
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104
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Yeo KR, Yeo WW. Inhibitory effects of verapamil and diltiazem on simvastatin metabolism in human liver microsomes. Br J Clin Pharmacol 2001; 51:461-70. [PMID: 11422004 PMCID: PMC2014477 DOI: 10.1046/j.1365-2125.2001.01386.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2000] [Accepted: 02/05/2001] [Indexed: 11/20/2022] Open
Abstract
AIMS To determine the effects of verapamil and diltiazem on simvastatin metabolism in human liver microsomes and to compare their inhibitory potencies and CYP3A4 inactivation parameters with those reported previously for mibefradil. METHODS Simvastatin metabolism was investigated in human liver microsomes in the presence and absence of verapamil or diltiazem (0.1-250 microM). Kinetics of CYP3A4 inactivation by verapamil and diltiazem were determined using testosterone as the substrate. RESULTS When verapamil was coincubated with simvastatin, IC50 values ranged from 23 to 26 microM for all major metabolites. The IC50 values ranged from 4.8 to 5.6 microM on preincubation of verapamil for 30 min in the presence of an NADPH-generating system. Corresponding IC50 values for diltiazem ranged from 110-127 microM and from 21-27 microM, respectively. Verapamil and diltiazem inhibited testosterone 6beta-hydroxylation in a time- and concentration-dependent manner, key features of mechanism-based inactivation. Values for the inactivation parameters kinact and KI were 0.15 +/- 0.04 min-1 (mean +/- s.d.) and 2.9 +/- 0.6 microM, respectively, for verapamil and 0.07 +/- 0.01 min-1 and 3.3 +/- 1.5 microM, respectively, for diltiazem. CONCLUSIONS The IC50 values for coincubation of verapamil and diltiazem were 46- and 220-fold higher, respectively, than those reported previously for mibefradil, and 16- and 71-fold higher, respectively, for preincubation. Thus, the results of this study suggest that verapamil and diltiazem are less likely than mibefradil to cause acute drug interactions with simvastatin in vivo. However, verapamil and diltiazem are moderate mechanism-based inhibitors of CYP3A4 and therefore may still cause significant inhibition of simvastatin metabolism in vivo during chronic therapy.
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Affiliation(s)
- K R Yeo
- Section of Clinical Pharmacology & Therapeutics, University of Sheffield, Royal Hallamshire Hospital, Glossop Road, Sheffield.
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105
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Siekmeier R, Lattke P, Mix C, Park JW, Jaross W. Dose dependency of fluvastatin pharmacokinetics in serum determined by reversed phase HPLC. J Cardiovasc Pharmacol Ther 2001; 6:137-45. [PMID: 11509920 DOI: 10.1177/107424840100600205] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Fluvastatin is an inhibitor of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, effectively lowering serum cholesterol concentrations. A high-performance liquid chromatography (HPLC) assay was developed that determined the pharmacokinetics of fluvastatin in healthy individuals after administration of 40 and 80 mg fluvastatin. METHODS The method was linear for serum concentrations between 10 ng/mL and 5,000 ng/mL, showing good coefficients of variations and sample stability. After administration of 40 mg fluvastatin, the mean values of the area under the serum concentration vs time curve (AUC), the maximum serum drug concentration (C(max)), the time to reach C(max) (t(max)), and the serum elimination half-life time were 528.5 +/-358.8 ng/mL x h, 149.6 +/-56.0 ng/mL, 60.0 +/-30.0 minutes, and 108.0 +/-67.9 minutes, respectively. The corresponding values for a dose of 80 mg fluvastatin were 1417.7 +/-879.2 ng/mL x h, 1024.7 +/-1085.1 ng/mL, 60.0 +/-21.2 minutes, and 106.0 +/-73.6 minutes, respectively. Doubling of the dose from 40 mg to 80 mg caused an overproportional increase of AUC and C(max). RESULTS AND CONCLUSION Results suggest that the measurement of fluvastatin serum concentrations by means of HPLC provides reliable data within the broad range of physiological serum concentrations. The pharmacokinetic data after administration of high doses (80 mg) showed an overproportional increase of AUC and C(max), suggesting a saturation of the hepatic first-pass effect. Thus, in patients treated with additional substances interfering with fluvastatin metabolism, fluvastatin serum concentrations should be analyzed.
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Affiliation(s)
- R Siekmeier
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Technical University, Dresden
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106
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Grip O, Janciauskiene S, Lindgren S. Pravastatin down-regulates inflammatory mediators in human monocytes in vitro. Eur J Pharmacol 2000; 410:83-92. [PMID: 11134659 DOI: 10.1016/s0014-2999(00)00870-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
There is experimental evidence that pravastatin, which is designed to inhibit the rate-limiting enzyme of cholesterol synthesis, can affect cell metabolism and proliferation. We therefore studied the effects of pravastatin on the generation of inflammatory mediators in non-stimulated and stimulated primary human monocytes in vitro. In our experimental model, pravastatin induced a dose-dependent inhibition of monocyte cholesterol synthesis (up to 67%), up-regulation of low density lipoprotein receptor mRNA (by about 35%) and reduction in intracellular cholesterol accumulation. In parallel, exposure of non-stimulated monocytes to various doses of pravastatin resulted in inhibition of monocyte chemoattractant protein-1 protein expression (up to 15-fold), reduction of tumour necrosis factor alpha (TNF-alpha) levels (up to 2.4-fold) and a total loss of metalloproteinase-9 activity in stimulated cells. Pravastatin at concentrations of 5, 100 and 500 microM caused an inhibition of TNF-alpha-induced cellular oxygen consumption from 2. 4- to 5.5-fold. These data extend the findings of potential anti-inflammatory actions of statins and also suggest the possibility for pravastatin use in a broader spectrum of inflammatory situations.
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Affiliation(s)
- O Grip
- Department of Medicine, Division of Gastroenterology and Hepatology, Lund University, University Hospital MAS, S-20502, Malmö, Sweden.
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107
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Ye LY, Firby PS, Moore MJ. Determination of lovastatin in human plasma using reverse-phase high-performance liquid chromatography with UV detection. Ther Drug Monit 2000; 22:737-41. [PMID: 11128243 DOI: 10.1097/00007691-200012000-00014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The authors have developed a simple, rapid HPLC assay with ultraviolet (UV) detection for the analytical determination of lovastatin and its acid in human plasma for a concentration range of 100-5,000 ng/mL. Sample clean-up involved the use of C10 solid-phase extraction cartridges. Our limit of quantitation was 100 ng/mL. Standard curves were linear from 100 to 5,000 ng/mL, with a correlation coefficient (r2) of 0.999 +/- 0.0002. Stored samples were stable at -70 degrees C for up to 4 months prior to reversed-phase HPLC analysis. This assay was able to measure steady-state lovastatin concentration (Css) at the initial dose level in a phase I trial of lovastatin as a modulator of apoptosis.
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Affiliation(s)
- L Y Ye
- Department of Experimental Therapeutics, Faculty of Pharmacy, University of Toronto, Ontario, Canada
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108
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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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109
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Plosker GL, Dunn CI, Figgitt DP. Cerivastatin: a review of its pharmacological properties and therapeutic efficacy in the management of hypercholesterolaemia. Drugs 2000; 60:1179-206. [PMID: 11129127 DOI: 10.2165/00003495-200060050-00011] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
UNLABELLED Cerivastatin is an HMG-CoA reductase inhibitor used for the treatment of patients with hypercholesterolaemia. The lipid-lowering efficacy of cerivastatin has been demonstrated in a number of large multicentre, randomised clinical trials. Earlier studies used cerivastatin at relatively low dosages of < or =0.3mg orally once daily, but more recent studies have focused on dosages of 0.4 or 0.8 mg/day currently recommended by the US Food and Drug Administration (FDA). Along with modest improvements in serum levels of triglycerides and high density lipoprotein (HDL)-cholesterol, cerivastatin 0.4 to 0.8 mg/day achieved marked reductions in serum levels of low density lipoprotein (LDL)-cholesterol (33.4 to 44.0%) and total cholesterol (23.0 to 30.8%). These ranges included results of a pivotal North American trial in almost 1000 patients with hypercholesterolaemia. In this 8-week study, US National Cholesterol Education Program (Adult Treatment Panel II) [NCEP] target levels for LDL-cholesterol were achieved in 84% of patients randomised to receive cerivastatin 0.8 mg/day, 73% of those treated with cerivastatin 0.4 mg/day and <10% of placebo recipients. Among patients with baseline serum LDL-cholesterol levels meeting NCEP guidelines for starting pharmacotherapy, 75% achieved target LDL-cholesterol levels with cerivastatin 0.8 mg/day. In 90% of all patients receiving cerivastatin 0.8 mg/day, LDL-cholesterol levels were reduced by 23.9 to 58.4% (6th to 95th percentile). Various subanalyses of clinical trials with cerivastatin indicate that the greatest lipid-lowering response can be expected in women and elderly patients. Cerivastatin is generally well tolerated and adverse events have usually been mild and transient. The overall incidence and nature of adverse events reported with cerivastatin in clinical trials was similar to that of placebo. The most frequent adverse events associated with cerivastatin were headache, GI disturbances, asthenia, pharyngitis and rhinitis. In the large pivotal trial, significant elevations in serum levels of creatine kinase and transaminases were reported in a small proportion of patients receiving cerivastatin but not in placebo recipients. As with other HMG-CoA reductase inhibitors, rare reports of myopathy and rhabdomyolysis have occurred with cerivastatin, although gemfibrozil or cyclosporin were administered concomitantly in most cases. Postmarketing surveillance studies in the US have been performed. In 3 mandated formulary switch conversion studies, cerivastatin was either equivalent or superior to other HMG-CoA reductase inhibitors, including atorvastatin, in reducing serum LDL-cholesterol levels or achieving NCEP target levels. Pharmacoeconomic data with cerivastatin are limited, but analyses conducted to date in the US and Italy suggest that cerivastatin compares favourably with other available HMG-CoA reductase inhibitors in terms of its cost per life-year gained. CONCLUSION Cerivastatin is a well tolerated and effective lipid-lowering agent for patients with hypercholesterolaemia. When given at dosages currently recommended by the FDA in the US, cerivastatin achieves marked reductions in serum levels of LDL-cholesterol, reaching NCEP target levels in the vast majority of patients. Thus, cerivastatin provides a useful (and potentially cost effective) alternative to other currently available HMG-CoA reductase inhibitors as a first-line agent for hypercholesterolaemia.
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Affiliation(s)
- G L Plosker
- Adis International Limited, Auckland, New Zealand.
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110
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Beaird SL. HMG-CoA reductase inhibitors: assessing differences in drug interactions and safety profiles. JOURNAL OF THE AMERICAN PHARMACEUTICAL ASSOCIATION (WASHINGTON, D.C. : 1996) 2000; 40:637-44. [PMID: 11029845 DOI: 10.1016/s1086-5802(16)31104-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To review the cytochrome P450 system and associated metabolic differences between the HMG-CoA reductase inhibitors. DATA SOURCES A MEDLINE search (1993-99) was conducted for English-language articles using key search terms including adverse drug reactions, cytochrome P450, drug metabolism, drug interactions, hydroxymethylglutaryl-CoA (HMG-CoA) reductase inhibitors, myopathy, and rhabdomyolysis. STUDY SELECTION Review articles, clinical trials, and case reports concerning HMG-CoA reductase inhibitor metabolism, drug interactions, and adverse drug reactions were evaluated. DATA EXTRACTION By the author. No software or assistants were used to extract information from the chosen studies. DATA SYNTHESIS The cytochrome P450 enzymes, which can be divided into families, subfamilies, and isoenzymes, act as a major catalyst for drug oxidation in the liver. CYP3A4 is a major enzyme, accounting for about 60% of drug metabolic capacity in the liver and 70% of such function in the intestine. Lovastatin, simvastatin, and atorvastatin are substrates of CYP3A4, whereas fluvastatin is metabolized by CYP2C9. Pravastatin is not extensively metabolized by either of these isoenzymes; rather, it is transported into hepatocytes by a sodium-independent, carrier-mediated uptake system that normally transports bile acids. Compared with other statins, pravastatin thus has a reduced potential for drug interactions with other substrates, inhibitors, or inducers of the CYP3A4 and CYP2C9 systems. CONCLUSION Pharmacists must understand the functions of these enzymes to identify potential drug interactions, especially in high-risk patient populations, and to make appropriate therapeutic recommendations that prevent or minimize adverse clinical outcomes.
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Affiliation(s)
- S L Beaird
- HealthTech Solutions, St. Louis, MO 63146, USA.
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111
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Sadeghi MM, Collinge M, Pardi R, Bender JR. Simvastatin modulates cytokine-mediated endothelial cell adhesion molecule induction: involvement of an inhibitory G protein. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:2712-8. [PMID: 10946302 DOI: 10.4049/jimmunol.165.5.2712] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Endothelial cell adhesion molecules (CAMs) E-selectin, ICAM-1, and VCAM-1 play variably important roles in immune-mediated processes. They are induced by the proinflammatory cytokines IL-1 and TNF-alpha, and NF-kappaB is required for the regulated expression of all three genes. Regulators of this pathway could potentially be potent immune modulators. We studied the effect of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, simvastatin, on cytokine-induced expression of CAMs in HUVEC. Unexpectedly, pretreatment with simvastatin potentiated the induction of all three endothelial CAMs by IL-1 and TNF, but not LPS or PMA, as detected by flow cytometry. Northern blot analysis demonstrated an increase in steady state IL-1-induced E-selectin mRNA levels in cells pretreated with simvastatin. This was associated with an increase in nuclear translocation of NF-kappaB, as detected by EMSA. The effect of simvastatin was reversed by mevalonate and geranylgeranyl pyrophosphate but not squalene, indicating that an inhibitory prenylated protein is involved in endothelial responses to proinflammatory cytokines. Pertussis toxin mimicked the effect of simvastatin, and the G protein activator NaF inhibited the cytokine-induced expression of endothelial CAMs, indicating that a Gialpha protein is involved. These results demonstrate that cytokine-mediated activation of the endothelium, and specifically CAM induction, can be modulated by a heterotrimeric G protein-coupled pathway. This may represent a "basal tone" of endothelial inactivation, which can either be disinhibited or amplified, depending on the stimulus.
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Affiliation(s)
- M M Sadeghi
- Division of Cardiovascular Medicine and Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, CT 06536, USA
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112
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Jemal M, Ouyang Z, Powell ML. Direct-injection LC-MS-MS method for high-throughput simultaneous quantitation of simvastatin and simvastatin acid in human plasma. J Pharm Biomed Anal 2000; 23:323-40. [PMID: 10933525 DOI: 10.1016/s0731-7085(00)00309-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A direct-injection liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS) method was developed and validated for the simultaneous quantitation in human plasma of the widely used cholesterol-lowering prodrug simvastatin and its in vivo generated active drug, simvastatin acid. The plasma samples were injected into the LC-MS-MS system after simply adding the internal standard solution in an aqueous buffer and centrifuging. The analytes in the buffered plasma samples were found to be stable for at least 24 h at 4 degrees C. The method was successfully validated under the challenging condition of using a large number of quality control (QC) samples including those in which the ratio of the simvastatin concentration to the simvastatin acid concentration was different from the concentration ratio in the calibration curve standards. Under the dual stabilizing conditions of lower temperature (4 degrees C) and lower plasma pH of 4.9, the in-process hydrolysis of simvastatin to simvastatin acid or the lactonization of simvastatin acid to simvastatin was minimized to < or = 1.0%. Although the entire run time for on-line cleanup and analysis was only 2.5 min, chromatographic base-line separation of simvastatin from simvastatin acid, which was required to avoid the interference by simvastatin acid with the simvastatin selected reaction monitoring channel, was achieved. The desired lower limit of quantitation of 0.5 ng/ml was achieved by injecting only an equivalent of 8.0 microl of the plasma sample. The extraction column lasted for at least 500 injections.
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Affiliation(s)
- M Jemal
- Bioanalytical Research, Metabolism and Pharmacokinetics, Bristol-Myers Squibb Pharmaceutical Research Institute, New Brunswick, NJ 08903-0191, USA.
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113
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Cartier N, Guidoux S, Rocchiccioli F, Aubourg P. Simvastatin does not normalize very long chain fatty acids in adrenoleukodystrophy mice. FEBS Lett 2000; 478:205-8. [PMID: 10930569 DOI: 10.1016/s0014-5793(00)01852-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
X-linked adrenoleukodystrophy (ALD) is a genetic demyelinating disorder characterized by accumulation of very long chain fatty acid (VLCFA) in tissues. Lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, normalizes VLCFA in fibroblasts and plasma from ALD patients. We dietary treated ALD mice with simvastatin, an analog of lovastatin with similar pharmacokinetics and effects on plasma VLCFA in ALD patients at 20 or 60 mg/kg/day for 6-12 weeks. No decrease of VLCFA content was observed in mouse tissues, including the brain. A significant increase of VLCFA was rather observed in the brain of ALD mice at 60 mg/kg/day.
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Affiliation(s)
- N Cartier
- Inserm U342, Hôpital Saint-Vincent de Paul, 82 avenue Denfert Rochereau, 75014, Paris, France.
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114
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Abstract
Cerivastatin sodium, a novel statin, is a synthetic, enantiomerically pure, pyridine derivative that effectively reduces serum cholesterol levels at microgram doses. Cerivastatin is readily and completely absorbed from the gastrointestinal tract, with plasma concentrations reaching a peak 2 to 3 hours postadministration followed by a monoexponential decay with an elimination half-life (t1/2beta) of 2 to 3 hours. Cerivastatin pharmacokinetics are linear: maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC) are proportional to the dose over the range of 0.05 to 0.8 mg. No accumulation is observed on repeated administration. Cerivastatin interindividual variability is described by coefficients of variation of approximately 30 to 40% for its primary pharmacokinetic parameters AUC, Cmax and t1/2beta. The mean absolute oral bioavailability of cerivastatin is 60% because of presystemic first-pass effects. Its pharmacokinetics are not influenced by concomitant administration of food nor by the time of day at which the dose is given. Age, gender, ethnicity and concurrent disease also have no clinically significant effects. Cerivastatin is highly bound to plasma proteins (>99%). The volume of distribution at steady state of about 0.3 L/kg indicates that the drug penetrates only moderately into tissue; conversely, preclinical studies have shown a high affinity for liver tissue, the target site of action. Cerivastatin is exclusively cleared via metabolism. No unchanged drug is excreted. Cerivastatin is subject to 2 main oxidative biotransformation reactions: demethylation of the benzylic methyl ether moiety leading to the metabolite M-1 [catalysed by cytochrome P450 (CYP) 2C8 and CYP3A4] and stereoselective hydroxylation of one methyl group of the 6-isopropyl substituent leading to the metabolite M-23 (catalysed by CYP2C8). The product of the combined biotransformation reactions is a secondary minor metabolite, M-24, not detectable in plasma. All 3 metabolites are active inhibitors of hydroxymethylglutaryl-coenzyme A reductase with a similar potency to the parent drug. Approximately 70% of the administered dose is excreted as metabolites in the faeces, and 30% in the urine. Metabolism by 2 distinct CYP isoforms renders cerivastatin relatively resistant to interactions arising from inhibition of CYP. If one of the pathways is blocked, cerivastatin can be effectively metabolised by the alternative route. In addition, on the basis of in vitro investigations, there is no evidence for either cerivastatin or its metabolites having any inducing or inhibitory activity on CYP. The apparent lack of any clinically relevant interactions with a variety of drugs commonly used by patients in the target population supports this favourable drug-drug interaction profile.
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Affiliation(s)
- W Mück
- Institute of Clinical Pharmacology, Bayer AG, Pharma Research Center, Wuppertal, Germany
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115
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Pan WJ, Gustavson LE, Achari R, Rieser MJ, Ye X, Gutterman C, Wallin BA. Lack of a clinically significant pharmacokinetic interaction between fenofibrate and pravastatin in healthy volunteers. J Clin Pharmacol 2000; 40:316-23. [PMID: 10709162 DOI: 10.1177/00912700022008874] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study was conducted to evaluate the potential pharmacokinetic interaction between fenofibrate and pravastatin. A total of 23 healthy adult volunteers received single-dose 201 mg fenofibrate alone, 201 mg fenofibrate + 40 mg pravastatin, and 40 mg pravastatin alone in a three-period crossover experiment. Plasma samples were collected at predetermined times and were analyzed with validated methods for the quantitation of fenofibric acid, pravastatin, and 3 alpha-hydroxy-isopravastatin (3 alpha-iso-PV). Pharmacokinetic parameters of these three compounds were calculated using noncompartmental methods and compared by analyses of variance and bioavailability assessments. Concomitant administration of fenofibrate and pravastatin did not affect the pharmacokinetics of either fenofibric acid or pravastatin. However, the AUC0-infinity and Cmax of 3 alpha-iso-PV were increased by 26% and 29%, respectively. The moderate increase in the formation of this pravastatin metabolite should not raise any clinical concerns due to its much lower pharmacological potency compared to pravastatin and lack of toxicity.
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Affiliation(s)
- W J Pan
- Department of Clinical Pharmacokinetics and Toxicokinetics, Abbott Laboratories, Abbott Park, Illinois 60064-6104, USA
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116
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Cai SR, Motoyama K, Shen KJ, Kennedy SC, Flye MW, Ponder KP. Lovastatin decreases mortality and improves liver functions in fulminant hepatic failure from 90% partial hepatectomy in rats. J Hepatol 2000; 32:67-77. [PMID: 10673069 DOI: 10.1016/s0168-8278(00)80191-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Liver insufficiency occurs when the liver cannot perform critical functions such as ammonia metabolism, gluconeogenesis, or production of coagulation factors The hypothesis of this study was that decreased function of existing hepatocytes may contribute to hepatic failure, and that the function of these cells might be increased pharmacologically. Lovastatin is a 3-hydroxy-3-methylglutaryl CoA reductase inhibitor that inhibits cholesterol biosynthesis and affects the activity of some signal transduction pathways and liver transcription factors. Changes in hepatic transcription factors during liver regeneration might result in decreased liver functions, and lovastatin might prevent these changes METHODS Rats received 90% partial hepatectomy (90% PH), and either lovastatin or vehicle alone daily. Survival and liver functions were assessed. RESULTS Lovastatin increased survival to 58% (vs. 6% in controls that received 90% PH without drug), decreased the peak ammonia level to 427 microM (vs. 846 microM in controls), increased the nadir of glucose to 88 mg/dl (vs. 57 mg/dl in controls), decreased the peak prothrombin time to 23 s (vs 29 s in controls), and decreased the peak activated partial thromboplastin time to 29 s (vs. 39 s in controls). The full survival and metabolic benefits were observed when lovastatin was started at 30 min after 90% PH, but lovastatin was less efficacious when started at later times. CONCLUSIONS Lovastatin increases the function of existing hepatocytes and might be used to improve liver function after extensive hepatic resection.
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Affiliation(s)
- S R Cai
- Department of Internal Medicine, Washington University School of Medicine, USA
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117
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Corsini A, Bellosta S, Baetta R, Fumagalli R, Paoletti R, Bernini F. New insights into the pharmacodynamic and pharmacokinetic properties of statins. Pharmacol Ther 1999; 84:413-28. [PMID: 10665838 DOI: 10.1016/s0163-7258(99)00045-5] [Citation(s) in RCA: 525] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The beneficial effects of statins are assumed to result from their ability to reduce cholesterol biosynthesis. However, because mevalonic acid is the precursor not only of cholesterol, but also of many nonsteroidal isoprenoid compounds, inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase may result in pleiotropic effects. It has been shown that several statins decrease smooth muscle cell migration and proliferation and that sera from fluvastatin-treated patients interfere with its proliferation. Cholesterol accumulation in macrophages can be inhibited by different statins, while both fluvastatin and simvastatin inhibit secretion of metalloproteinases by human monocyte-derived macrophages. The antiatherosclerotic effects of statins may be achieved by modifying hypercholesterolemia and the arterial wall environment as well. Although statins rarely have severe adverse effects, interactions with other drugs deserve attention. Simvastatin, lovastatin, cerivastatin, and atorvastatin are biotransformed in the liver primarily by cytochrome P450-3A4, and are susceptible to drug interactions when co-administered with potential inhibitors of this enzyme. Indeed, pharmacokinetic interactions (e.g., increased bioavailability), myositis, and rhabdomyolysis have been reported following concurrent use of simvastatin or lovastatin and cyclosporine A, mibefradil, or nefazodone. In contrast, fluvastatin (mainly metabolized by cytochrome P450-2C9) and pravastatin (eliminated by other metabolic routes) are less subject to this interaction. Nevertheless, a 5- to 23-fold increase in pravastatin bioavailability has been reported in the presence of cyclosporine A. In summary, statins may have direct effects on the arterial wall, which may contribute to their antiatherosclerotic actions. Furthermore, some statins may have lower adverse drug interaction potential than others, which is an important determinant of safety during long-term therapy.
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Affiliation(s)
- A Corsini
- Institute of Pharmacological Sciences, University of Milan, Italy.
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118
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Yeo KR, Yeo WW, Wallis EJ, Ramsay LE. Enhanced cholesterol reduction by simvastatin in diltiazem-treated patients. Br J Clin Pharmacol 1999; 48:610-5. [PMID: 10583033 PMCID: PMC2014381 DOI: 10.1046/j.1365-2125.1999.00066.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To investigate whether an interaction between diltiazem and the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor simvastatin may enhance the cholesterol-lowering response to simvastatin in diltiazem-treated patients. METHODS One hundred and thirty-five patients attending the Sheffield hypertension clinic who started consecutively on simvastatin for primary or secondary prevention of coronary heart disease (CHD) during the 2 years June, 1996-May 1998 were surveyed. From the clinic records we extracted and recorded absolute and percentage cholesterol responses to the starting dose of simvastatin and coprescription of diltiazem. RESULTS The cholesterol reduction for the 19 patients on diltiazem was 33.3% compared with 24.7% in the remaining 116 patients (median difference 8.6%, 95% CI 1.1-12.2%, P<0.02). The interindividual variability of cholesterol response to simvastatin was greater for patients not taking diltiazem than for those patients taking diltiazem. The ratio of the variances in response for the nondiltiazem group relative to the diltiazem group was 1.34 at 10 mg simvastatin daily (not significant, 95% CI 0.16-4.11), and 3.42 at 20 mg daily (P<0.01, 95% CI 1.26-7.18). Concurrent diltiazem therapy (P<0.04), age (P=0.001) and starting dose of simvastatin (P=0.002) were found to be significant independent predictors of percentage cholesterol response. CONCLUSIONS Patients who take both simvastatin and diltiazem may need lower doses of simvastatin to achieve the recommended reduction in cholesterol. The pharmacokinetic and pharmacodynamic aspects of this interaction need further study to confirm an enhanced effect on cholesterol reduction, and exclude an increased risk of adverse events.
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Affiliation(s)
- K R Yeo
- University Section of Clinical Pharmacology and Therapeutics, Royal Hallamshire Hospital, Sheffield, UK.
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119
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Park HJ, Galper JB. 3-Hydroxy-3-methylglutaryl CoA reductase inhibitors up-regulate transforming growth factor-beta signaling in cultured heart cells via inhibition of geranylgeranylation of RhoA GTPase. Proc Natl Acad Sci U S A 1999; 96:11525-30. [PMID: 10500210 PMCID: PMC18067 DOI: 10.1073/pnas.96.20.11525] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Transforming growth factor-beta (TGFbeta) signaling has been shown to play a role in cardiac development as well as in the pathogenesis of cardiovascular disease. Prior studies have suggested a relationship between cholesterol metabolism and TGFbeta signaling. Here we demonstrate that induction of the cholesterol metabolic pathway by growth of embryonic chicken atrial cells in medium supplemented with lipoprotein-depleted serum coordinately decreased the expression of the TGFbeta type II receptor (TGFbetaRII), TGFbeta(1), and TGFbeta signaling as measured by plasminogen activator inhibitor-1 (PAI-1) promoter activity. Inhibition of the cholesterol metabolic pathway by the hydrophobic 3-hydroxy-3-methylglutaryl CoA (HMGCoA) reductase inhibitors, simvastatin and atorvastatin, reversed the effect of lipoprotein-depleted serum and up-regulated TGFbetaRII expression, whereas the hydrophilic HMGCoA reductase inhibitor, pravastatin, had no effect. Simvastatin stimulated the expression of TGFbetaRII, TGFbeta(1), and PAI-1 at the level of transcription. Experiments using specific inhibitors of different branches of the cholesterol metabolic pathway demonstrated that simvastatin exerted its effect on TGFbeta signaling by inhibition of the geranylgeranylation pathway. C3 exotoxin, which specifically inactivates geranylgeranylated Rho GTPases, mimicked the effect of simvastatin on PAI-1 promoter activity. Cotransfection of cells with a PAI-1 promoter-reporter and a dominant-negative RhoA mutant increased PAI-1 promoter activity, whereas cotransfection with a dominant-active RhoA mutant decreased PAI-1 promoter activity. These data support the conclusion that TGFbeta signaling is regulated by RhoA GTPase and demonstrate a relationship between cholesterol metabolism and TGFbeta signaling. Our data suggest that in patients treated with HMGCoA reductase inhibitors, these agents may exert effects independent of cholesterol lowering on TGFbeta signaling in the heart.
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Affiliation(s)
- H J Park
- Cardiovascular Research Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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120
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Gupta AK, Katz HI, Shear NH. Drug interactions with itraconazole, fluconazole, and terbinafine and their management. J Am Acad Dermatol 1999; 41:237-49. [PMID: 10426895 DOI: 10.1016/s0190-9622(99)70055-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A drug interaction develops when the effect of a drug is increased or decreased or when a new effect is produced by the prior, concurrent, or subsequent administration of the other. Before prescribing a drug, it is important to obtain a thorough drug history of the prescription and nonprescription medications taken by the patient. The nonprescription medications may include items such as nutritional supplements and herbal medications. The risk of side effects is an inevitable consequence of drug use. The frequency of adverse reactions is increased in those patients receiving multiple medications. Drug interactions reported in animal or in vitro studies may not necessarily develop in humans. When drug interactions are observed with a particular agent, it cannot be automatically assumed that all closely related drugs will necessarily produce the same interaction. However, caution is advised until sufficient experience accrues. The prescriber should not overestimate or underestimate the potential for a given drug interaction on the basis of personal experience alone. Drug interactions will not necessarily occur in every patient who is given a particular combination of drugs known to produce an interaction. For a clinically significant drug interaction to be manifest, several other factors may be relevant other than just using the two drugs. In many instances drug interactions can be predicted and therefore avoided if the pharmacodynamic effects, the pharmacokinetic properties, and the mechanisms of action of the 2 drugs in question are known. In the case of contraindicated drugs, it may be possible to use an alternative agent.
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Affiliation(s)
- A K Gupta
- Division of Dermatology, Department of Medicine, University of Toronto,London, Ontario, N6K 1L6, Canada.
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121
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Nakad A, Bataille L, Hamoir V, Sempoux C, Horsmans Y. Atorvastatin-induced acute hepatitis with absence of cross-toxicity with simvastatin. Lancet 1999; 353:1763-4. [PMID: 10347994 DOI: 10.1016/s0140-6736(99)00569-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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122
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Becquemont L, Funck-Brentano C, Jaillon P. Mibefradil, a potent CYP3A inhibitor, does not alter pravastatin pharmacokinetics. Fundam Clin Pharmacol 1999; 13:232-6. [PMID: 10226769 DOI: 10.1111/j.1472-8206.1999.tb00344.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dramatic drug-drug interactions have been observed between several HMG-CoA reductase inhibitors and cytochrome P450 3A (CYP3A) inhibitors. The aim of the present study was to investigate the effects of mibefradil, a potent CYP3A inhibitor, on pravastatin pharmacokinetics. 12 healthy volunteers were included in this open-label one-period study. Pravastatin pharmacokinetics (following a single oral dose of 40 mg) was studied in the absence of mibefradil (day 1) and after repeated doses (100 mg/day) of mibefradil (day 8). Pravastatin pharmacokinetics after repeated doses of 40 mg/day was also studied in association with repeated doses (100 mg/day) of mibefradil (day 16). Pravastatin area under the plasma concentration vs. time curve (AUC0-infinity) and Cmax in the absence of mibefradil on day 1 (170 [117 to 395] ng h/mL and 91 [72 to 200] ng/mL respectively, geometric mean [95% confidence intervals]) were not significantly altered in the presence of mibefradil on day 8 (224 [174 to 381] ng h/mL and 124 [72 to 200] ng/mL) and on day 16 (200 [137 to 555] ng h/mL and 91 [74 to 184] ng/mL). Tmax of pravastatin in the absence of mibefradil (0.9 +/- 0.1 h, arithmetic mean +/- SD) was slightly delayed in the presence of mibefradil on day 8 and 16 (1.1 +/- 0.3 and 1.2 +/- 0.3 h respectively, p < 0.01 for both comparisons). The results of the present study confirm the lack of pharmacokinetic interactions between mibefradil and pravastatin and indicate that pravastatin may be safely prescribed in the presence of potent CYP3A inhibitors.
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Affiliation(s)
- L Becquemont
- Service de Pharmacologie, CHU Saint Antoine, Université Paris VI, France
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123
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Tan A, Levrey H, Dahm C, Polunovsky VA, Rubins J, Bitterman PB. Lovastatin induces fibroblast apoptosis in vitro and in vivo. A possible therapy for fibroproliferative disorders. Am J Respir Crit Care Med 1999; 159:220-7. [PMID: 9872842 DOI: 10.1164/ajrccm.159.1.9802104] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Diseases associated with pathological fibroproliferation represent a major cause of morbidity and mortality. Despite the importance of this class of disorders, current therapy is of limited value, and no therapy is available to reduce the fibroblast population size within existing fibrotic lesions. In this regard, constitutive expression of growth-promoting genes can sensitize cells to undergo apoptosis. Studies in our laboratory have demonstrated that lovastatin potently induces apoptosis in fibroblasts constitutively expressing Myc, and that lung fibroblasts isolated from fibrotic lesions constitutively express growth-promoting genes. In this study, we sought to determine if nontransformed lung fibroblasts would manifest susceptibility to lovastatin-induced apoptosis similar to that observed in fibroblasts ectopically expressing Myc. Here we show that clinically achievable concentrations of lovastatin induce apoptosis in normal and fibrotic lung fibroblasts in vitro, as evidenced by acridine orange staining, terminal transferase nick end translation (TUNEL), and DNA laddering. Apoptosis of human lung fibroblasts was dose- and time-dependent, and blocked by exogenous mevalonic acid. Furthermore, apoptosis was associated with decreased levels of mature Ras, a molecule directly implicated in fibroblast rescue from apoptosis. The ability of lovastatin to induce fibroblast apoptosis in vivo was examined using a guinea pig wound chamber model. Lovastatin (5 microM, 8 d) reduced granulation tissue formation in the wound chambers by 64.7%, with associated ultrastructural evidence of fibroblast apoptosis. These findings support further study of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors as potential therapy for patients with fibroproliferative disorders.
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Affiliation(s)
- A Tan
- Department of Medicine, Pulmonary, Allergy and Critical Care Division, and Department of Internal Medicine, University of Minnesota Medical School, Minneapolis, USA
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124
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Essig M, Nguyen G, Prié D, Escoubet B, Sraer JD, Friedlander G. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors increase fibrinolytic activity in rat aortic endothelial cells. Role of geranylgeranylation and Rho proteins. Circ Res 1998; 83:683-90. [PMID: 9758637 DOI: 10.1161/01.res.83.7.683] [Citation(s) in RCA: 202] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (HRIs) have been recently shown to prevent atherosclerosis progression. Clinical benefit results from combined actions on various components of the atherosclerotic lesion. This study was designed to identify the effects of HRI on one of these components, the endothelial fibrinolytic system. Aortas isolated from rats treated for 2 days with lovastatin (4 mg/kg body wt per day) showed a 3-fold increase in tissue plasminogen activator (tPA) activity. In a rat aortic endothelial cell line (SVARECs) and in human nontransformed endothelial cells (HUVECs), HRI induced an increase in tPA activity and antigen in a time- and concentration-dependent manner. In SVARECs, the maximal response was observed when cells were incubated for 48 hours with 50 micromol/L HRI. An increase of tPA mRNA was also in evidence. In contrast, HRI inhibited plasminogen activator inhibitor-1 activity and mRNA. The effects of HRI were reversed by mevalonate and geranylgeranyl pyrophosphate, but not by LDL cholesterol and farnesyl pyrophosphate, and were not induced by alpha-hydroxyfarnesyl phosphonic acid, an inhibitor of protein farnesyl transferase. C3 exoenzyme, an inhibitor of the geranylgeranylated-activated Rho protein, reproduced the effect of lovastatin on tPA and plasminogen activator inhibitor-1 activity and blocked its reversal by geranylgeranyl pyrophosphate. The effect of HRI was associated with a disruption of cellular actin filaments without modification of microtubules. A disrupter of actin filaments, cytochalasin D, induced the same effect as lovastatin on tPA, whereas a disrupter of microtubules, nocodazole, did not. In conclusion, HRI can modify the fibrinolytic potential of endothelial cells, likely via inhibition of geranylgeranylated Rho protein and disruption of the actin filaments. The resulting increase of fibrinolytic activity of endothelial cells may contribute to the beneficial effects of HRI in the progression of atherosclerosis.
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Affiliation(s)
- M Essig
- INSERM U 426 and the Department of Physiology, Faculté de Médecine Xavier Bichat, Université Denis Diderot, Paris, France
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125
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Kuhlmann J, Mück W, Bischoff H, Keutz E, Llewellyn M. Cerivastatin (BAY w 6228): A Novel HMG-CoA Reductase Inhibitor. ACTA ACUST UNITED AC 1998. [DOI: 10.1111/j.1527-3466.1998.tb00357.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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126
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Alegret M, Verd JC, Díaz C, Hernández G, Adzet T, Sánchez RM, Laguna JC. Effect of hypolipidemic drugs on key enzyme activities related to lipid metabolism in normolipidemic rabbits. Eur J Pharmacol 1998; 347:283-91. [PMID: 9653895 DOI: 10.1016/s0014-2999(98)00096-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The effect of atorvastatin (3 mg kg(-1) day(-1)), simvastatin (3 mg kg(-1) day(-1)) and bezafibrate (100 mg kg(-1) day(-1)) administered for 4 weeks to male New Zealand white rabbits on enzyme activities related to lipid metabolism has been studied. Only the statins reduced plasma cholesterol values, while none of the drugs modified plasma triglyceride or high density lipoprotein (HDL)-cholesterol concentrations, nor the activity of enzymes such as hepatic diacylglycerol acyltransferase, lipoprotein lipase or hepatic lipase, directly involved in triglyceride metabolism. Both statins elicited similar increases in the hepatic microsomal 3-hydroxy-3-methyl-glutaryl Coenzyme A (CoA) reductase activity (147 and 109% induction for simvastatin and atorvastatin, respectively), and none of the drugs assayed modified hepatic acyl-coenzyme A:cholesterol acyltransferase activity significantly. Only bezafibrate induced a significant 57% reduction in the activity of hepatic microsomal cholesterol 7alpha-hydroxylase. Regarding the rate limiting enzyme of phosphatidylcholine biosynthesis, CTP:phosphocholine cytidylyl transferase, atorvastatin and bezafibrate behaved similarly, decreasing the enzyme activity in the liver by 45% and 54%, respectively; simvastatin induced no modification of this activity. The reduction of CTP:phosphocholine cytidylyl transferase activity is not caused by a direct inhibition of the enzyme by bezafibrate and atorvastatin. Further, the inhibitory effect of atorvastatin appears to be unrelated to the inhibition of 3-hydroxy-3-methyl-glutaryl CoA reductase elicited in vivo.
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Affiliation(s)
- M Alegret
- Dept. Farmacología y Química Terapéutica, Facultad de Farmacia, Núcleo Universitario de Pedralbes, Barcelona, Spain
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127
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Pharmaceutical economics & health policy. Clin Ther 1997. [DOI: 10.1016/s0149-2918(97)80138-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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