Effect of Atorvastatin on Cyclosporine Pharmacokinetics in Liver Transplant Recipients

Atherogenic Dyslipidemia After Liver Transplantation: Mechanisms and Clinical Implications

Cardiovascular disease (CVD), particularly atherosclerosis-associated CVD, is a major cause of long-term mortality after liver transplantation (LT). The liver is central in lipid homeostasis, and changes associated with insulin resistance, weight gain, adipose tissue inflammation, and development of nonalcoholic fatty liver disease (NAFLD) after LT promote atherogenesis. These factors synergistically alter lipid homeostasis, thereby leading to the production of proatherogenic lipoproteins, which contribute to the heighted risk of CVD-associated events observed in LT recipients. Although the exact mechanism promoting this shift of a proatherogenic lipoprotein profile is currently not known, the choice of immunosuppression and preexisting metabolic risk factors (ie, NAFLD) are likely contributors. This shift in proatherogenic lipoprotein subparticles presents clinical challenges as the traditional lipid profile employed in clinical practice may not fully capture this atherogenic risk. This review focuses on lipoprotein metabolism and atherogenesis in LT recipients.

The Underutilization, Adverse Reactions and Efficacy of Statins after Liver Transplant: A Meta-Analysis and Systematic Review

(1) Background: Treatment of dyslipidemia via statin therapy in the non-liver transplant (LT) population is associated with a mortality benefit; however, the impact of statin therapy in post-LT population is not well-defined. This meta-analysis seeks to investigate the safety and efficacy of statin therapy in post-LT patients. (2) Methods: A systematic literature search on Medline and EMBASE database was conducted. A single-arm proportional meta-analysis and conventional pair-wise meta-analysis were performed to compare different outcomes with a random effects model. (3) Results: A total of 11 studies were included in this study, with 697 LT recipients identified to be on statin therapy. Statins were underutilized with only 32% (95% CI: 0.15–0.52) of 1094 post-LT patients on therapy. The incidence of adverse events of 14% (95% CI: 0.05–0.25) related to statin therapy was low. A significant mortality benefit was noted in patients on statin therapy with HR = 0.282 (95% CI: 0.154–0.517, p < 0.001), and improved lipid profiles post LT. The use of statins also significantly decreased odds of graft rejection (OR = 0.33; 95% CI: 0.15–0.73) and hepatocellular carcinoma (HCC) recurrence (HR = 0.32, 95% CI: 0.11–0.89). (4) Conclusions: Statin therapy is safe and efficacious in post-LT patients. Future studies to evaluate the effects of interactions between statins and immunosuppressant therapy are warranted.

Statin Safety and Associated Adverse Events: A Scientific Statement From the American Heart Association

One in 4 Americans >40 years of age takes a statin to reduce the risk of myocardial infarction, ischemic stroke, and other complications of atherosclerotic disease. The most effective statins produce a mean reduction in low-density lipoprotein cholesterol of 55% to 60% at the maximum dosage, and 6 of the 7 marketed statins are available in generic form, which makes them affordable for most patients. Primarily using data from randomized controlled trials, supplemented with observational data where necessary, this scientific statement provides a comprehensive review of statin safety and tolerability. The review covers the general patient population, as well as demographic subgroups, including the elderly, children, pregnant women, East Asians, and patients with specific conditions such as chronic disease of the kidney and liver, human immunodeficiency viral infection, and organ transplants. The risk of statin-induced serious muscle injury, including rhabdomyolysis, is <0.1%, and the risk of serious hepatotoxicity is ≈0.001%. The risk of statin-induced newly diagnosed diabetes mellitus is ≈0.2% per year of treatment, depending on the underlying risk of diabetes mellitus in the population studied. In patients with cerebrovascular disease, statins possibly increase the risk of hemorrhagic stroke; however, they clearly produce a greater reduction in the risk of atherothrombotic stroke and thus total stroke, as well as other cardiovascular events. There is no convincing evidence for a causal relationship between statins and cancer, cataracts, cognitive dysfunction, peripheral neuropathy, erectile dysfunction, or tendonitis. In US clinical practices, roughly 10% of patients stop taking a statin because of subjective complaints, most commonly muscle symptoms without raised creatine kinase. In contrast, in randomized clinical trials, the difference in the incidence of muscle symptoms without significantly raised creatinine kinase in statin-treated compared with placebo-treated participants is <1%, and it is even smaller (0.1%) for patients who discontinued treatment because of such muscle symptoms. This suggests that muscle symptoms are usually not caused by pharmacological effects of the statin. Restarting statin therapy in these patients can be challenging, but it is important, especially in patients at high risk of cardiovascular events, for whom prevention of these events is a priority. Overall, in patients for whom statin treatment is recommended by current guidelines, the benefits greatly outweigh the risks.

Dyslipidemia and lipid-lowering treatment in a hematopoietic stem cell transplant cohort: 25 years of follow-up data

BACKGROUND

Dyslipidemia is common after hematopoietic stem cell transplantation (HSCT). Few data regarding the time course of lipid profiles after HSCT, the effect of multiple transplantations, and efficacy and safety of lipid-lowering treatments are available.

OBJECTIVE

The objective of the study was to determine the prevalence and treatment of dyslipidemia over a 25-year period in a large, single-center cohort.

METHODS

One thousand one hundred ninety-six adult patients (≥16 years) who underwent HSCT during 1973 to 2013 and who survived ≥100 days were studied retrospectively.

RESULTS

The prevalence of dyslipidemia before transplantation was 36% and 28% in the autologous and allogeneic groups, respectively (P < .001). Three months after HSCT, the prevalence rose to 62% and 74% (P < .001), and at 25 years, it was 67% and 89%. Lipid profiles were similar after first and subsequent transplants. Baseline dyslipidemia (odds ratio [OR] = 2.72), allogeneic transplant (OR = 2.44), and age ≥ 35 years (OR = 2.33) were independent risk factors for dyslipidemia at 1 year. Lipid-lowering treatment was given to 223 (19%) patients, primarily in the form of statins (86%) and was associated with a decrease in total cholesterol from 246 to 192 mg/dL (P < .01) and from 244 to 195 mg/dL (P < .001) in the autologous and allogeneic groups, respectively. There were 10 cases (4%) of muscle symptoms prompting cessation of lipid-lowering therapy, including 1 case of rhabdomyolysis. The OR for dyslipidemia among patients who suffered a cardiovascular event (conditional logistic regression) was 3.5 (95% confidence interval = 1.6-7.7, P = .002).

CONCLUSION

This study confirms that dyslipidemia is a common and long-lasting phenomenon among both allogeneic and autologous HSCT patients. Statins are effective, generally well-tolerated and should be highly recommended for the management of post-HSCT dyslipidemia.

Liver Transplantation: the Role of Metabolic Syndrome

OPINION STATEMENT

The long-term survival in liver transplant recipients (LTRs) is currently at an historical high level stemming from improvement in perioperative care, infection control, and immunosuppression medications. However, compared to the general population, LTRs have decreased survival. Metabolic diseases like hypertension, dyslipidemia, type 2 diabetes, and obesity are key determinants of long-term mortality in LTRs. The incidence and prevalence of these metabolic comorbidities is considerably higher in LTRs and likely results from a combination of factors including exposure to chronic immunosuppression, weight gain, and recurrence of chronic liver disease after liver transplantation (LT). Although there is currently little guidance in managing these metabolic conditions post-LT, recommendations are often extrapolated from non-transplant cohorts. In the current review, we explore the relationship between metabolic syndrome and its comorbidities in LTRs.

Long-term outcome after liver transplantation

Liver transplantation is a life-saving therapy for patients with end-stage liver disease, acute liver failure, and liver tumors. Over the past 4 decades, improvements in surgical techniques, peritransplant intensive care, and immunosuppressive regimens have resulted in significant improvements in short-term survival. Focus has now shifted to addressing long-term complications and improving quality of life in liver recipients. These include adverse effects of immunosuppression; recurrence of the primary liver disease; and management of diabetes, hypertension, dyslipidemia, obesity, metabolic syndrome, cardiovascular disease, renal dysfunction, osteoporosis, and de novo malignancy. Issues such as posttransplant depression, employment, sexual function, fertility, and pregnancy must not be overlooked, as they have a direct impact on the liver recipient's quality of life. This review summarizes the latest data in long-term outcome after liver transplantation.

Hyperlipidemia after allogeneic stem cell transplantation: prevalence, risk factors, and impact on prognosis

Hyperlipidemia is one of the late complications after allogeneic stem cell transplantation (SCT). Although intrahepatic cholestasis caused by chronic graft-versus-host disease (GVHD) or calcineurin inhibitors has been considered as possible etiologies, its prevalence, risk factors, and impact on prognosis have not been investigated well. We performed a retrospective analysis of 194 patients who underwent allogeneic SCT between 1995 and 2008 in our institute and survived more than 100 d after SCT. Overall, 83 (42.8%) and 99 (50.8%) patients developed hypercholesterolemia (≥240 mg/dL) and hypertriglyceridemia (≥200 mg/dL), respectively. In multivariate analysis, the development of chronic GVHD (hazard ratio [HR] 2.04, p < 0.05) and steroid use (HR 2.24, p < 0.01) were independently associated with hypercholesterolemia, while administration of calcineurin inhibitors was not. As for the prognostic impact, multivariate analysis showed that the patients with hypercholesterolemia had a tendency of lower rate of relapse (HR: 0.44, p = 0.07). There was no difference in non-relapse mortality or overall survival between the groups. In conclusion, the development of hypercholesterolemia is regarded as one of the symptoms accompanied with chronic GVHD and might indicate a better control of the primary disease.

Cardiovascular risk factors following orthotopic liver transplantation: predisposing factors, incidence and management

BACKGROUND

Liver transplantation is the standard of care for acute and chronic causes of end-stage liver disease. Advances in medical therapy and surgical techniques have led to improvement of patient and graft survival rates following orthotopic liver transplantation. However, the prevalence of post-transplant cardiovascular complications has been rising with increased life expectancy after liver transplantation.

AIMS

To determine the incidences, risk factors, and treatment for hypertension, hyperlipidaemia, diabetes, and obesity in the post-liver transplantation population.

METHODS

We performed a review of relevant studies available on the PubMed database that provided information on the incidence, risk factors and treatment for cardiovascular complications that develop in the post-liver transplantation population.

RESULTS

Current immunosuppressive agents have improved patient and graft survival rates. However, long-term exposure to these agents has been associated with development of systemic and metabolic complications including hypertension, hyperlipidaemia, diabetes mellitus and obesity. Cardiovascular disease remains one of the most common causes of death in liver transplant patients with functional grafts.

CONCLUSIONS

Liver transplant recipients have a higher risk of cardiovascular complications compared with the nontransplant population. Post-transplant cardiac risk stratification and aggressive treatment of cardiovascular complications, including modification of risk factors and tailoring of immunosuppressive regimen, is imperative to prevent serious complications.

Coronary artery disease in orthotopic liver transplantation: pretransplant assessment and management

The prevalence of coronary artery disease in end-stage liver disease is only now being recognized. Liver transplant patients are a high risk subgroup for coronary artery disease, even if asymptomatic. Coronary artery disease is a predictor of poor outcomes; therefore, identification of those at risk must be a key clinical priority. However, risk assessment is particularly difficult as many of the available diagnostic tools have either proven to be unhelpful or remain to be validated. Risk factor profiling has been unable to identify those at risk and commonly underestimates risk. The high negative predictive value of Dobutamine stress echo, when target heart rates are achieved, allows it to be used to identify a low risk group. For all other patients, proceeding to invasive coronary angiography is often necessary, and the risks of the procedure can be reduced by a transradial approach. Pharmacological reduction of the consequences of coronary artery disease can be limited by the underlying liver disease. Revascularization pre-transplantation is recommended in international guidelines but has demonstrated little evidence of benefit. Surgical revascularization carries an increased risk in these patients and is commonly performed pre-transplantation, although combined liver and cardiac surgery has been described. Percutaneous coronary intervention is increasingly used with patients requiring anti-platelet medication for up to one year after intervention. We present a review of all these issues and the evidence for assessing and managing these high-risk patients.

Worsening of hyperglycemia due to atorvastatin in a renal transplant patient

New-onset diabetes mellitus post-renal transplantation [post-transplantation diabetes mellitus (PTDM)] and impaired glucose tolerance are among the most serious adverse metabolic disturbances of kidney transplants. We report a renal transplant patient whose mild post-transplant hyperglycaemia considerably worsened upon substituting atorvastatin for pravastatin. The patient was a 58-years-old Caucasian man who underwent living, non-related kidney transplantation. The mean blood sugar level (BSL) following transplantation was 113.8 mg/dl. In an attempt to reduce LDL cholesterol, atorvastatin 40 mg/day was substituted for pravastatin. Soon after commencement of atorvastatin, polydipsia and polyuria appeared. Both fasting and 2-h post-prandial BSL values increased, while there was no change in the patient's medications, dietary habits and renal function. Upon reverting back to pravastatin, BSL promptly declined to the previously mentioned baseline values. Since PTDM is a strong independent factor of graft failure, cardiovascular events and mortality, physicians should be made aware of this possible adverse effect of atorvastatin on glucose tolerance.

Safety and effectiveness of ezetimibe in liver transplant recipients with hypercholesterolemia

Hypercholesterolemia is a common problem among transplant recipients. Despite package-insert warnings about the potential side effects of the use of statins in patients with chronic liver disease, they are often prescribed for liver transplant recipients. Unlike statins, ezetimibe acts through inhibition of enterohepatic recirculation of lipids. We report the effectiveness and safety of ezetimibe among liver transplant recipients because this has been evaluated previously only in kidney and heart transplant patients. A consecutive cohort of 25 liver graft recipients with serum low-density lipoprotein (LDL) levels > 100 mg/dL (2.5 mmol/L) after a mean (+/-standard deviation) of 55 +/- 21 months following liver transplantation received ezetimibe (10 mg orally every day) for at least 6 months. Serum lipid profiles, liver and renal function tests, and dosages and blood levels of the immunosuppression drugs at baseline, 3 months, and 6 months were prospectively collected. The overall mean age was 58 +/- 12 years, and 56% were males. Statin therapy and fibrates were already being used in 32% and 20% of recipients for elevated LDL and/or triglycerides, respectively. The immunosuppression regimen included cyclosporine in 48% of subjects, tacrolimus in 32%, sirolimus in 48%, and mycophenolate mofetil in 44%; only 12% were on oral prednisone with a maximum daily dose of 5 mg. After ezetimibe was started, an 18% reduction in LDL values was observed [at baseline, 147 +/- 35 mg/dL (3.8 +/- 0.9 mmol/L), and at 6 months, 120 +/- 31 mg/dL (3.1 +/- 0.8 mmol/L); P = 0.010]. After 6 months, an additional 32% achieved the target LDL level of <100 mg/dL. None of the remaining variables, including immunosuppression drug levels, varied significantly during ezetimibe therapy. None of the subjects required adjustments in their pharmacological dosages. One discontinued ezetimibe 3 months later because of cost, 2 subjects had minimal nausea, 1 subject had myalgias without a rise in creatine phosphokinase, and 1 subject had a transient elevation (3-5 times) in liver enzymes from baseline with increases in the total and indirect bilirubin levels. In conclusion, among liver transplant recipients, hypercholesterolemia can be effectively treated with ezetimibe with few side effects and no interaction with immunosuppressive regimens.

Orthotopic liver transplantation and what to do during follow-up: recommendations for the practitioner

Improvements in surgical technique and the introduction of several new immunosuppressive medications mean that outcome after orthotopic liver transplantation (OLT) has improved continuously over the past 15 years. Given the increasing longevity of patients after OLT, the recognition and prevention of long-term complications after transplantation have become ever more important. With respect to graft function, physicians responsible for the everyday care of patients following transplantation should be particularly aware of the risk of late and chronic rejection episodes and of recurrence of the underlying liver disease. The major challenge of post-transplant care is, however, how best to prevent and manage the long-term adverse effects caused by the immunosuppressive medications prescribed. Screening investigations for early diagnosis of malignancy, strict control of cardiovascular risk factors, preservation of renal function, and prevention of infections are, therefore, fundamental. This Review suggests guidelines for the management of OLT recipients to improve long-term survival, overall outcome and health-related quality of life.

Reducing the risks of cardiovascular disease in liver allograft recipients

Liver allograft recipients are at increased risk of death from cerebrovascular and cardiovascular disease. We propose the following strategy of risk-reduction, based on currently available literature. Lifestyle: standard advice should be given (avoidance of smoking, excess alcohol and obesity, adequate exercise, reduction of excess sodium intake). Hypertension: target blood pressure should be 140/90 mmHg or lower, but for those with diabetes or renal disease, 130/80 mmHg or lower. For patients without proteinuria, antihypertensive therapy should be initiated with a calcium channel blocker and for those with proteinuria, an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker. If monotherapy fails to achieve adequate response, calcium channel blockers and ACE-inhibitors or angiotensin II receptor blockers should be combined. If hypertension remains uncontrolled, an alpha-blocker may be added. Consideration should be given to changing immunosuppression and avoiding use of calcineurin inhibitors. Diabetes: recipients should be regularly screened for diabetes. For patients with new-onset diabetes after transplant, stepwise therapy should be guided by HbA1c concentrations, as with type II diabetes mellitus. Hyperlipidemia: annual screening of lipid profile should be undertaken, with treatment thresholds and targets based on those advocated for the high risk general population. Dietary intervention is appropriate for all patients. A statin should be considered as the first line treatment to achieve specified targets. In patients receiving a calcineurin inhibitor, Pravastatin should be commenced at a dose of 10 mg/day. In patients receiving other forms of immunosuppression, pravastatin may be commenced at a dose of 20 mg/day. Liver tests should be monitored and patients warned to report myalgia. If monotherapy is inadequate, ezetimibe or a fibrate may be added. Consideration may be given to change in immunosuppression if combination lipid-lowering therapy proves inadequate.

Review article: drug hepatotoxicity

BACKGROUND

Drug toxicity is the leading cause of acute liver failure in the United States. Further understanding of hepatotoxicity is becoming increasingly important as more drugs come to market.

AIMS

(i) To provide an update on recent advances in our understanding of hepatotoxicity of select commonly used drug classes. (ii) To assess the safety of these medications in patients with pre-existing liver disease and in the post-liver transplant setting. (iii) To review relevant advances in toxicogenomics which contribute to the current understanding of hepatotoxic drugs.

METHODS

A Medline search was performed to identify relevant literature using search terms including 'drug toxicity, hepatotoxicity, statins, thiazolidinediones, antibiotics, antiretroviral drugs and toxicogenomics'.

RESULTS

Amoxicillin-clavulanic acid is one of the most frequently implicated causes of drug-induced liver injury worldwide. Statins rarely cause clinically significant liver injury, even in patients with underlying liver disease. Newer thiazolidinediones are not associated with the degree of liver toxicity observed with troglitazone. Careful monitoring for liver toxicity is warranted in patients who are taking antiretrovirals, especially patients who are co-infected with hepatitis B and C. Genetic polymorphisms among enzymes involved in drug metabolism and HLA types may account for some of the differences in individual susceptibility to drug hepatotoxicity.

CONCLUSIONS

Drug-induced hepatotoxicity will remain a problem that carries both clinical and regulatory significance as long as new drugs continue to enter the market. Future results from ongoing multicentre collaborative efforts may help contribute to our current understanding of hepatotoxicity associated with drugs.

Long-term care of the liver transplant recipient

As survival increases after liver transplantation, common issues that arise involve immunosuppression-related complications and primary health care. Proper emphasis on the prevention and treatment of post-liver transplant complications, such as diabetes mellitus, dyslipidemia, renal dysfunction, osteoporosis, and obesity, requires careful screening and long-term surveillance to minimize the progression of these complications. Active involvement by internists and subspecialists is necessary and a multidisciplinary approach should be undertaken. Liver transplantation should be viewed as a lifelong commitment by both patient and physician.

Role of P-glycoprotein in statin drug interactions

Understanding the mechanisms of drug interactions with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) has become increasingly important because of the potential for serious adverse effects, most notably myopathy. Most of the evidence supports the role of cytochrome P450 (CYP) isoenzymes in many of these drug interactions. However, P-glycoprotein (P-gp), an efflux protein located in the gastrointestinal tract, placenta, kidneys, brain, and liver, may also play a role. Results of several studies with in vitro models have shown that lovastatin, simvastatin, and atorvastatin are inhibitors for P-gp and may be substrates for this transporter as well. Pravastatin and fluvastatin consistently demonstrate no significant inhibition of P-gp. Drug interaction studies involving statins and digoxin support a role for P-gp. Many additional drugs such as diltiazem, verapamil, itraconazole, ketoconazole, and cyclosporine, as well as dietary supplements such as St. John's wort and grapefruit juice, interact with statins and are modulators of both CYP3A4 and P-gp. However, the role of P-gp in these specific drug interactions remains unclear.

Statins' dosage in patients with renal failure and cyclosporine drug-drug interactions in transplant recipient patients

Dyslipidemia is frequent in patients with renal failure and in transplant recipient patients. This lead to a wide use of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) in patients with impaired renal function or in patients treated with cyclosporine as post-transplantation immunosuppressive therapy. As a result, it is crucial for those patients' physicians to be aware of how to handle these drugs when renal function is impaired and/or when cyclosporine is co-administered. Most statins have an extensive hepatic elimination and the renal route is usually a minor elimination pathway. However, pharmacokinetic alterations have been described for some of these drugs in patients with renal insufficiency. Cyclosporine is a widely used immunosuppresive therapy in solid organ transplant patients and drug-drug interactions are likely to occur when statins and cyclosporine are administered together. Those interactions may theoretically result in increased statins and/or cyclosporine serum levels with potential muscle and/or renal toxicity. As a result, caution is warranted if concurrent administration is performed. In this review, we synthesized the data from the literature on (1) the pharmacokinetics and dosage adjustment of atorvastatin, fluvastatin, pravastatin, rosuvastatin, and simvastatin in patients with renal failure and (2) the potential drug-drug interactions between these drugs and cyclosporine in transplant recipient patients.

Cyclosporine Pharmacokinetics and Dosing Modifications in Human Immunodeficiency Virus-Infected Liver and Kidney Transplant Recipients

BACKGROUND

With advances in antiretroviral therapy, many human immunodeficiency virus (HIV)-infected individuals are living longer and developing end-stage renal or hepatic disease requiring transplantation. Maintaining the viability of the transplant and suppressing HIV replication requires concomitant use of immunosuppressants (e.g., cyclosporine) and antiretrovirals (e.g., protease inhibitors or nonnucleoside reverse transcriptase inhibitors), which leads to drug interactions. To assist in appropriate clinical management of HIV-infected transplant recipients, the authors describe the pharmacokinetic interactions between cyclosporine and the antiretroviral medications, and required modifications of cyclosporine dosing.

METHODS

Eighteen HIV-infected subjects with end-stage kidney or liver disease underwent transplantation. Subjects had pharmacokinetic studies before transplantation and for up to 2 years posttransplantation (at weeks 2-4, 12, 28, 52, and 104). Protease inhibitors, nonnucleoside reverse transcriptase inhibitors, and cyclosporine concentrations were measured by liquid chromatography-mass spectrometry in plasma and whole blood, respectively.

RESULTS

Subjects using protease inhibitors and cyclosporine had a threefold increase in cyclosporine area under the curve (4,190+/-2,180-11,900+/-1,600 ng*hr/mL, P<0.01), necessitating an 85% reduction in cyclosporine dose over a 2-year period (1.3+/-1.5-0.2+/-0.0 mg/kg/dose), leading to a progressive increase in oral cyclosporine bioavailability (R=0.92, P<0.02). Subjects on nonnucleoside reverse-transcriptase inhibitors showed minimal interactions with cyclosporine, and subjects on both HIV treatments had intermediate responses.

CONCLUSIONS

HIV-infected transplant recipients on protease inhibitors require markedly lower doses of cyclosporine, with continued lowering of the cyclosporine dose over time and ongoing cyclosporine trough monitoring because of progressively increasing cyclosporine bioavailability. Medication changes must be carefully managed to avoid insufficient immunosuppression or toxicity resulting from drug interactions.

Atorvastatin does not affect the pharmacokinetics of cyclosporine in renal transplant recipients

OBJECTIVE

The aim of the present study was to evaluate the possible influence of atorvastatin on the pharmacokinetics of cyclosporine (INN ciclosporin) and its main metabolites, AM1 and AM9, in renal transplant recipients.

METHODS

Whole blood samples from 18 renal transplanted patients on cyclosporine-based immunosuppressive therapy were collected prior to and after 4 weeks of treatment with atorvastatin (10 mg/day) and analysed with regard to both cyclosporine and its main metabolites, AM1 and AM9, using a specific chromatographic method with ultraviolet detection.

RESULTS

On average, AUC(0-12) [area under the whole blood concentration versus time curve in the dosing interval (0-12 h)] of cyclosporine was 5% (-16, 5) (90% confidence interval) lower upon co-administration with atorvastatin. No statistically significant changes in any of the calculated pharmacokinetic variables [AUC(0-12), maximum whole blood concentration (C(max)), whole blood concentration 12 h post dose (C(12)), time to C(max) (t(max)), terminal half-life (t(1/2))] for cyclosporine or the two metabolites, AM1 and AM9, upon atorvastatin treatment were observed. On average, atorvastatin did not affect the ratio between the CYP3A4-mediated metabolite AM9 and cyclosporine, suggesting that atorvastatin does not affect the CYP3A4 metabolism of cyclosporine to any significant extent. However, the influence of atorvastatin on the ratio between AM9 and cyclosporine showed large interindividual variability.

CONCLUSION

The results of this study indicate that atorvastatin does not, on average, affect cyclosporine pharmacokinetics in renal transplant recipients.