Effects of atazanavir/ritonavir or fosamprenavir/ritonavir on the pharmacokinetics of rosuvastatin.

BACKGROUND: Rosuvastatin (RSV) is a potent statin with a lower potential for drug interactions. However, recent data have revealed unexpected increases in RSV concentrations with lopinavir/ritonavir. The objective is to study the pharmacokinetic interaction of RSV with atazanavir/ritonavir (ATV/RTV) or fosamprenavir/ritonavir (FPV/RTV). METHODS: In a prospective pharmacokinetic drug interaction study, six HIV-seronegative, healthy adult volunteers received single 10-mg doses of RSV at baseline and after 6 days of ATV/RTV and FPV/RTV, with 6-day washout periods. Plasma concentrations of RSV and its metabolites, N-desmethyl-RSV and RSV-lactone, were measured by using a internally validated tandem mass spectrometric (LC-MS/MS) method over 24 hours. RESULTS: Compared to baseline, the area under the plasma concentration-time curve (AUC 0-24h) and maximum plasma concentration (Cmax) of RSV increased by 213% and 600%, respectively, and the time to reach Cmax was shorter (1.75 h vs. 2.91 h) when given with ATV/RTV (P < 0.05). However, coadministration with FPV/RTV did not significantly affect the pharmacokinetics of RSV. The AUC 0-24h of N-desmethyl-RSV was not significantly affected by either combinations, but that of RSV-lactone increased (P < 0.05) by 61% and 76% after coadministration with ATV/RTV and FPV/RTV, respectively. CONCLUSION: ATV/RTV significantly increases the plasma concentrations of rosuvastatin, most likely by increasing rosuvastatin's oral bioavailability. Dose limitations of RSV with ATV/RTV may be needed.

Safety and efficacy of simvastatin for the treatment of dyslipidemia in human immunodeficiency virus-infected patients receiving efavirenz-based highly active antiretroviral therapy.

STUDY OBJECTIVES: To evaluate the safety and efficacy of simvastatin for treatment of dyslipidemia in patients with the human immunodeficiency virus (HIV) who were receiving efavirenz-based highly active antiretroviral therapy (HAART), and to evaluate the effect of simvastatin when added to efavirenz on CD4(+) count, HIV viral load, and frequency of attainment of patient-specific National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III lipid goals. DESIGN: Retrospective medical record review. SETTING: Veterans Affairs health care system in Dallas, Texas. PATIENTS: Thirteen HIV-infected men who received a stable efavirenz-based HAART regimen concurrently with simvastatin 20 mg/day, and 19 HIV negative men who received simvastatin 20 mg/day (controls). MEASUREMENTS AND MAIN RESULTS: Demographic, clinical, and laboratory data were collected before and after starting simvastatin. Reductions in lipid profile values in the HIV-infected group versus HIV-negative group were as follows: total cholesterol -20% versus -28% (p=0.15), low-density lipoprotein cholesterol (LDL) -36% versus -41% (p=0.06), non-high-density lipoprotein cholesterol (non-HDL) -22% versus -33% (p=0.212), and total cholesterol:HDL ratio -33% versus -30% (p=0.26). These effects were seen without any documented adverse drug reactions or changes in viral and immunologic control. However, 28% fewer HIV-infected patients were able to achieve NCEP ATP III LDL goals compared with HIV-negative subjects. CONCLUSION: These preliminary comparative data suggest that simvastatin can be safely and effectively used to treat dyslipidemia in HIV-infected patients receiving efavirenz-based HAART without compromising viral or immunologic control. However, our results are suggestive of slight lessening of the LDL-lowering effects, which might be explained by the known reduction in simvastatin levels with efavirenz. Furthermore, fewer HIV-infected patients were able to meet their NCEP ATP III goals compared with HIV-negative controls, highlighting the difficulty in treating this population to current standards of care.

A multimodal, evidence-based approach to achieve lipid targets in the treatment of antiretroviral-associated dyslipidemia: case report and review of the literature.

Metabolic abnormalities associated with the treatment of human immunodeficiency virus (HIV) infection are well-recognized problems that increase cardiovascular risk. As a result of the complexity of treating both HIV- and antiretroviral-related comorbidities, strategies that improve adverse drug events while maintaining viral control are in critical need. Although guidelines have somewhat helped in the general approach and in first-line strategies for managing dyslipidemia in patients receiving antiretrovirals, a paucity of data exist to guide clinicians in treating patients whose conditions are refractory to first-line options or who are at substantial risk for cardiovascular events. Further complicating the choice of lipid-lowering strategy is the lack of randomized controlled data from the HIV-affected population and a concern about clinically significant drug-drug interactions. We describe an HIV-infected patient with efavirenz-associated dyslipidemia at very high cardiovascular risk who had not achieved his primary or secondary lipid goals despite 2 years of treatment in a lipid specialty clinic. Lipid control was accomplished in 10 weeks with a targeted, stepwise approach of switching efavirenz to nevirapine, followed by rosuvastatin 20 mg/day, which was sustained for at least 10 months. Of most importance, this outcome was achieved without any clinically significant alteration in virologic or immunologic control. This case report highlights the potential for a pharmacist-guided, multistep approach that addresses HIV-related dyslipidemia and incorporates the pharmacokinetic literature to guide lipid-lowering therapy and promote the attainment of goals based on current standards of care.

Multicenter evaluation of vancomycin dosing: emphasis on obesity.

BACKGROUND: There is a paucity of data available regarding the dosing of antimicrobials in obesity. However, data are available demonstrating that vancomycin should be dosed on the basis of actual body weight. METHODS: This study was conducted at 2 tertiary care medical centers that did not have pharmacy-guided vancomycin dosing programs or other institutional vancomycin dosing policies or protocols. Patients who received vancomycin between July 1, 2003, and June 30, 2006, were stratified by body mass index and randomly selected from the computer-generated queries. Patients >or=18 years of age with a creatinine clearance of at least 60 mL/min who received vancomycin for at least 36 hours were included. RESULTS: Data were collected on a random sampling of 421 patients, stratified by body mass index, who met the inclusion criteria. Most patients in each body mass index category received a fixed dose of vancomycin 2 g daily divided into 2 doses (underweight 82%, normal weight 90%, overweight 86%, and obese 91%). Adequate initial dosing (>or=10 mg/kg/dose) was achieved for 100% of underweight, 99% of normal weight, 93.9% of overweight, and 27.7% of obese patients (P < .0001). Ninety-seven percent of underweight, 46% of normal weight, 1% of overweight, and 0.6% of obese patients received >or=15 mg/kg/dose recommended by several Infectious Diseases Society of America guidelines. Pharmacists also failed to correct inadequate dosing because only 3.3% of patients receiving less than 10 mg/kg/dose had their regimen changed in the first 24 hours of therapy. CONCLUSION: In this multicenter pilot study, obese patients routinely received inadequate empiric vancomycin using a lenient assessment of dosing. Greater efforts should be undertaken to ensure patients receive weight-based dosing because inadequate dosing can lead to subtherapeutic concentrations and potentially worse clinical outcomes.

Improvement in insulin sensitivity and dyslipidemia in protease inhibitor-treated adult male patients after switch to atazanavir/ritonavir.

BACKGROUND: Treatment of human immunodeficiency virus (HIV) with protease inhibitors (PIs) is associated with insulin resistance, triglyceride-rich dyslipidemia, and fat redistribution. Atazanavir (ATV), a potent once-daily PI, has been recognized for its convenience to patients, and some studies describe improved lipid metabolism. However, its effects on insulin sensitivity have not been elucidated. We conducted this study to test the hypothesis that ATV improves insulin resistance and dyslipidemia. METHODS: We prospectively studied 9 HIV-infected men with dyslipidemia (median age, 53 years; baseline triglyceride level, >200 mg/dL) on stable PI-containing antiretroviral therapy who elected to change PI therapy to ritonavir-boosted ATV therapy, dose of 300/100 mg. We measured insulin resistance at baseline and after 12 weeks of therapy using a hyperinsulinemic euglycemic clamp (insulin dose, 200 mU/m minute). Fasting lipid profiles and body composition (whole-body dual energy x-ray absorptiometry) were also measured at baseline and after 12 weeks. RESULTS: All 9 patients completed the study and maintained undetectable viral loads (<50 copies/mL) and stable CD4 counts. After 12 weeks, insulin sensitivity significantly improved (+28%; P = 0.008) in all patients. Triglyceride levels also improved. CONCLUSIONS: Using the gold-standard euglycemic clamp, ritonavir-boosted ATV therapy improved PI-induced insulin resistance among dyslipidemic HIV-infected men on PI-based antiretroviral therapy. These findings were not attributable to a change in body weight and provide further evidence for ATV's unique metabolic profile among the PIs.

Lipid-lowering efficacy and safety after switching to atazanavir-ritonavir-based highly active antiretroviral therapy in patients with human immunodeficiency virus.

STUDY OBJECTIVE: To evaluate the efficacy, safety, and lipid-lowering effects after switching from a non-atazanavir-containing, protease inhibitor-based highly active antiretroviral therapy (HAART) to atazanavir-ritonavir-based HAART in patients infected with human immunodeficiency virus (HIV). DESIGN: Multicenter, noncontrolled, retrospective study. SETTING: Three tertiary teaching hospitals. PATIENTS: Thirty-six patients with HIV infection, aged 18 years or older, who were receiving non-atazanavir-containing, protease inhibitor-based HAART that was switched to atazanavir 300 mg-ritonavir 100 mg-based HAART without changes in nucleoside reverse transcriptase inhibitors and confounders known to alter serum lipid levels. MEASUREMENTS AND MAIN RESULTS: Lipid profiles measured 4 weeks-6 months before the switch, as well as follow-up lipid profiles measured 4 weeks-6 months after receiving the new HAART regimen, were evaluated. The switch resulted in the following changes in lipid levels: total cholesterol -9% (p=0.002), low-density lipoprotein cholesterol -13% (p<0.001), high-density lipoprotein cholesterol (HDL) -2% (p=0.431), triglycerides -23% (p=0.007), non-HDL -11% (p=0.002), total cholesterol:HDL ratio -10% (p=0.004), and triglyceride:HDL ratio -24% (p=0.019). A subgroup analysis was conducted on the lipid profiles of nine patients who still met the strict inclusion and exclusion criteria up to 9 months after the switch; it showed that the reductions in their lipid profiles were sustained. In addition, 33% more patients achieved their National Cholesterol Education Panel (NCEP) Adult Treatment Panel (ATP) III cholesterol goals. No significant changes were noted in median (interquartile range) CD4+ counts (372 [236-551] and 361 [217-464] cells/mm(3), p=0.118) or in number of patients with undetectable HIV viral loads ([defined as < 50 copies/ml] 32/36 and 31/36 patients, p>0.05) between baseline and after the switch, respectively. CONCLUSION: Switching to an atazanavir-ritonavir-based HAART regimen was associated with significant improvement in lipid profiles, similar to those seen in clinical trials, without compromising safety or viral and immunologic control. In addition, more patients were able to achieve their NCEP ATP III goals.

Combination thiazolidinedione and fibrate effect on high-density lipoprotein cholesterol (HDL-C) concentration in a Veterans Affairs patient population.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a coronary heart disease (CHD) risk equivalent warranting aggressive management of dyslipidemia and tight glycemic control. Recent reports demonstrate a paradoxic decrease in high-density lipoprotein cholesterol (HDL-C) with thiazolidinedione (TZD) and fibrate combination therapy. OBJECTIVE: Evaluate change in HDL-C from start of combination therapy to 1 year and assess the proportion, characteristics, and regimens of patients who developed a ≥20% decrease in HDL-C from baseline. METHODS: Patients with T2DM treated concurrently with a combination of TZD and fibrate were identified through retrospective query from a Veterans Affairs medical center database. HDL-C was recorded for 1 year after patients started combination therapy. Logistic regression analysis was performed to determine any predictors of HDL-C change. RESULTS: A total of 322 patients were included in the analysis. There was no significant differences in mean ± standard deviation HDL-C from baseline to end point (36.8 ± 8.5 to 40.3 ± 11.8 mg/dL; P = 0.097). There was a subset of patients identified (13%; n = 43) on combination therapy who experienced a ≥20% reduction in HDL-C. Of these patients, a decrease in HDL-C was more likely to occur with fenofibrate-based regimens (odds ratio 3.08, 95% confidence interval 1.22 to 7.75; P = 0.018). There was a trend toward more of these patients in this subset to have the combination of rosiglitazone and fenofibrate in their profiles (odds ratio 2.82, 95% confidence interval 0.98 to 8.0; P = 0.064). CONCLUSION: Our study demonstrated that a subset of patients with T2DM experienced a paradoxic decrease in HDL-C when taking a fibrate and TZD combination.

Evidence-based treatment recommendations for uremic bleeding.

Uremic bleeding syndrome is a recognized consequence of renal failure and can result in clinically significant sequelae. Although the pathophysiology of the condition has yet to be fully elucidated, it is believed to be multifactorial. This article is a review of both the normal hemostatic and homeostatic mechanisms that operate within the body to prevent unnecessary bleeding, as well as an in-depth discussion of the dysfunctional components that contribute to the complications associated with uremic bleeding syndrome. As a result of the multifactorial nature of this syndrome, prevention and treatment options can include one or a combination of the following: dialysis, erythropoietin, cryoprecipitate, desmopressin, and conjugated estrogens. Here, these treatment options are compared with regard to their mechanism of action, and onset and duration of efficacy. An extensive review of the clinical trials that have evaluated each treatment is also presented. Lastly, we have created an evidence-based treatment algorithm to help guide clinicians through most clinical scenarios, and answered common questions related to the management of uremic bleeding.

A retrospective study of the lipid-lowering efficacy and safety of ezetimibe added to hydroxy methylglutaryl coenzyme A reductase therapy in HIV-infected patients with hyperlipidemia.

BACKGROUND: Abnormalities in lipid metabolism are a well-described consequence of human immunodeficiency virus (HIV) infection being treated with highly active antiretroviral therapies (HAART). OBJECTIVE: The purpose of this study is to evaluate the lipid-lowering efficacy and safety of ezetimibe added to existing hydroxy methylglutaryl coenzyme A reductase (statin) therapy in HIV-infected patients with hyperlipidemia. METHODS: This is a retrospective study utilizing a comprehensive electronic patient registry to identify all adult HIV-infected patients seen at the Dallas Veterans Affairs (VA) Medical Center during a 4-year period from October 1, 2002 through October 1, 2006. RESULTS: A total of 26 HIV-infected patients initiated on ezetimibe 10 mg were identified, with 14 adult males meeting strict criteria for inclusion. Median age was 54 years (interquartile range [IQR], 45-59) with a median duration of HIV of 13 years, CD4 count of 513 cells/mm(3) (IQR, 289-736), and 9 of 14 patients had undetectable viral loads at baseline. Initiation of ezetimibe 10 mg resulted in a significant decrease in total cholesterol (TC) from baseline (-12.9%, P = 0.001); low-density lipoprotein cholesterol (LDL-C; -25.7%, P = 0.001); and non-high-density lipoprotein cholesterol (non-HDL-C; -23.9%, P = 0.001). There was also a nonsignificant decrease in triglycerides (15.8%, P = 0.43), and an increase in number of patients achieving National Cholesterol Education Program/Adult Treatment Panel III goal for LDL-C after initiation of ezetimibe (+20.9%, P = 0.125). These improvements occurred without adverse effects or changes in virologic and immunologic control. CONCLUSION: Addition of ezetimibe to existing statin therapy in HIV-infected VA patients treated with HAART significantly reduces TC, LDL-C, and non-HDL-C concentrations without apparent side effects or compromising of virologic control.

Temporal relationship between use of NSAIDs, including selective COX-2 inhibitors, and cardiovascular risk.

BACKGROUND AND OBJECTIVE: The search for NSAIDs with less gastrointestinal toxicity led to the introduction of the selective cyclo-oxygenase-2 (COX-2) inhibitors. However, following their introduction into the market, concerns have developed regarding their safety, particularly their cardiovascular safety. The purpose of this study was to assess the cardiovascular risk (events included were myocardial infarction, stroke and myocardial infarction-related deaths) associated with long-term (>180 days of exposure) and short-term (or=35 years of age who received celecoxib, rofecoxib, ibuprofen, etodolac and naproxen from 1 January 1999 through 31 December 2001, were included. Multivariate Cox proportional hazard models were used to analyse the relationship between cardiovascular risk and NSAID use, including selective COX-2 inhibitor use, while adjusting for various risk factors. RESULTS: We identified 12 188 exposure periods (11 930 persons) and 146 cardiovascular events over the entire study period. Compared with long-term ibuprofen use, long-term use of celecoxib (adjusted hazard ratio [HR] 3.64; 95% CI 1.36, 9.70) and rofecoxib (adjusted HR 6.64; 95% CI 2.17, 20.28) was associated with a significant increase in cardiovascular risk. When restricted to patients >or=65 years of age, the cardiovascular risks associated with long-term celecoxib (adjusted HR 7.36; 95% CI 1.62, 33.48) and rofecoxib (adjusted HR 13.24; 95% CI 2.59, 67.68) use increased. Short-term use of celecoxib (adjusted HR 0.75; 95% CI 0.42, 1.35) and rofecoxib (adjusted HR 0.85; 95% CI 0.39, 1.86) was not associated with any significant change in cardiovascular risk when compared with short-term ibuprofen use. Neither long- nor short-term exposure to naproxen and etodolac was associated with cardionegative or cardioprotective effects when compared with ibuprofen use. CONCLUSIONS: The findings of this observational study, along with recent clinical trial results, suggest that prolonged exposure to selective COX-2 inhibitors may be associated with an increased risk of adverse cardiovascular outcomes.

Effects of perioperative antiinflammatory and immunomodulating therapy on surgical wound healing.

Patients with various rheumatologic and inflammatory disease states commonly require drugs known to decrease the inflammatory or autoimmune response for adequate control of their condition. Such drugs include nonsteroidal antiinflammatory drugs (NSAIDs), cyclooxygenase (COX)-2 inhibitors, corticosteroids, disease-modifying antirheumatic drugs (DMARDs), and biologic response modifiers. These drugs affect inflammation and local immune responses, which are necessary for proper wound healing in the perioperative setting, thereby potentially resulting in undesirable postoperative complications. Such complications include wound dehiscence, infection, and impaired collagen synthesis. The end result is delayed healing of soft tissue and bone wounds. The current literature provides insight into the effect of some of these drugs on wound healing. For certain drugs, such as methotrexate, trials have been conducted in humans and direct us on what to do during the perioperative period. Whereas with other drugs, we must rely on either small-animal studies or extrapolation of data from human studies that did not specifically look at wound healing. Unfortunately, no clear consensus exists on the need and optimum time for withholding therapy before surgery. Likewise, clinicians are often uncertain of the appropriate time to resume therapy after the procedure. For those drugs with limited or no data in this setting, the use of pharmacokinetic properties and biologic effects of each drug should be considered individually. In some cases, discontinuation of therapy may be required up to 4 weeks before surgery because of the long half-lives of the drugs. In doing so, patients may experience an exacerbation or worsening of disease. Clinicians must carefully evaluate individual patient risk factors, disease severity, and the pharmacokinetics of available therapies when weighing the risks and benefits of discontinuing therapy in the perioperative setting.

The role of oral direct thrombin inhibitors in the treatment of venous thromboembolism.

Unfractionated heparin and warfarin have been the mainstay of treatment of venous thromboembolism (VTE) for approximately half a century. However, both agents are difficult to dose accurately, require frequent blood testing and dosage adjustment, and can cause serious adverse effects. Oral direct thrombin inhibitors may provide more predictable anticoagulation with oral dosing, without the need for frequent blood test monitoring and without the adverse effects seen with conventional agents. The oral direct thrombin inhibitor closest to being marketed is ximelagatran, which has been through phase III trials. Available data thus far suggest that the efficacy and safety of this agent may allow it to replace both heparin (and low-molecular-weight heparin) and warfarin for VTE treatment and long-term prophylaxis. Concerns about ximelagatran that require further study are a 5-9% rate of transient elevation in liver enzyme levels, drug interactions, how patient adherence can be ensured in the absence of blood tests, and whether alterations in renal or hepatic function will require dosage adjustments. Although there is more to learn about ximelagatran, available data suggest that it is likely to be the most significant therapeutic advance in this area in over 50 years.

Atazanavir for the treatment of human immunodeficiency virus infection.

Atazanavir is the first once-daily protease inhibitor for the treatment of human immunodeficiency virus type 1 infection and should be used only in combination therapy, as part of a highly active antiretroviral therapy (HAART) regimen. In addition to being the most potent protease inhibitor in vitro, atazanavir has a distinct cross-resistance profile that does not confer resistance to other protease inhibitors. However, resistance to other protease inhibitors often confers clinically relevant resistance to atazanavir. Currently, atazanavir is not a preferred protease inhibitor for initial HAART regimens. In treatment-naive patients, atazanavir can be given as 400 mg/day. However, atazanavir should be pharmacologically boosted with ritonavir in treatment-experienced patients or when coadministered with either tenofovir or efavirenz. Patients who receive atazanavir experience similar rates of adverse events compared with patients receiving comparator regimens. An exception is an increased risk of asymptomatic hyperbilirubinemia, which is due to competitive inhibition of uridine diphosphate-glucuronosyltransferase 1A1. Although hyperbilirubinemia is a common adverse drug reaction of atazanavir therapy (22-47%), fewer than 2% of patients discontinue atazanavir therapy because of this adverse effect. Common adverse effects reported with atazanavir include infection, nausea, vomiting, diarrhea, abdominal pain, headache, peripheral neuropathy, and rash. Of significance, fewer abnormalities have been observed in plasma lipid profiles in patients treated with atazanavir compared with other protease inhibitor-containing regimens. As with other protease inhibitors, atazanavir is also a substrate and moderate inhibitor of the cytochrome P450 (CYP) system, in particular CYP3A4 and CYP2C9. Clinically significant drug interactions include (but are not limited to) antacids, proton pump inhibitors, histamine type 2 receptor antagonists, tenofovir, diltiazem, irinotecan, simvastatin, lovastatin, St. John's wort, and warfarin. We conclude that atazanavir is a distinctively characteristic protease inhibitor owing to its in vitro potency, once-daily dosing, distinct initial resistance pattern, and infrequent association with metabolic abnormalities.

Tegaserod-induced myocardial infarction: case report and hypothesis.

Serotonin (5-hydroxytryptamine [5-HT])1 receptor agonists, such as those used for treating migraine, can cause coronary artery contraction, coronary spasm, and even myocardial infarction. Tegaserod maleate is a relatively new 5-HT4 receptor agonist with moderate affinity for the 5-HT1 receptor. Currently, it is approved only for treatment of irritable bowel syndrome in women who have constipation as the primary symptom. However, it is also being administered as a promotility agent in patients with gastroparesis. Since tegaserod has affinity for the 5-HT1 receptor, it is plausible that tegaserod could cause the same types of cardiovascular adverse events seen with agents prescribed for management of migraine. We report the first case of a man who experienced a myocardial infarction after receiving only two 6-mg doses of tegaserod; we also provide a hypothesis regarding this event. When considering prescribing a drug with 5-HT1 receptor agonist activity, clinicians should review the patient's medical history specifically for the presence of underlying cardiovascular risk factors.