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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment of HIV infection with potent combination antiretroviral therapy has resulted in major improvement in overall survival, immune function and the incidence of opportunistic infections. However, HIV infection and treatment has been associated with the development of metabolic complications, including hyperlipidaemia, diabetes mellitus, hypertension, lipodystrophy and osteopenia. Safe pharmacological treatment of these complications requires an understanding of the drug-drug interactions between antiretroviral drugs and the drugs used in the treatment of metabolic complications. Since formal studies of most of these interactions have not been performed, predictions must be based on our understanding of the metabolism of these agents. All HIV protease inhibitors are metabolised by and inhibit cytochrome P450 (CYP) 3A4. Ritonavir is the most potent inhibitor of CYP3A4. Ritonavir and nelfinavir also induce a host of CYP isoforms as well as some conjugating enzymes. The non-nucleoside reverse transcriptase inhibitor delavirdine potently inhibits CYP3A4, whereas nevirapine and efavirenz are inducers of CYP3A4. Drug interaction studies have been performed with HIV protease inhibitors and HMG-CoA reductase inhibitors. Coadministration of ritonavir plus saquinavir to HIV-seronegative volunteers resulted in increased exposure to simvastatin acid by 3059%. Atorvastatin exposure increased by 347%, but exposure to active atorvastatin increased by only 79%. Conversely, pravastatin exposure decreased by 50%. Similar results have been obtained with combinations of simvastatin and atorvastatin with other HIV protease inhibitors. Thus, the lactone prodrugs simvastatin and lovastatin should not be used with HIV protease inhibitors. Atorvastatin may be used with caution. Although there are no formal studies available, calcium channel antagonists and repaglinide may have significant interactions and toxicity when used with HIV protease inhibitors because of their metabolism by CYP3A4. Sulfonylurea drugs utilise mainly CYP2C9 for metabolism, and this isoenzyme may be induced by ritonavir and nelfinavir with a resulting decrease in efficacy of the sulfonylurea. Losartan may have increased effect when coadministered with ritonavir and nelfinavir because of the induction of CYP2C9 and the expected increase in formation of the active metabolite, E-3174. Overall, well-designed drug-drug interaction studies at steady state are needed to determine whether antiretroviral drugs may be safely coadministered with many of the drugs used in the treatment of the metabolic complications of HIV infection.
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PMID:Interactions between antiretroviral drugs and drugs used for the therapy of the metabolic complications encountered during HIV infection. 1240 66

Protease inhibitors are drugs that are commonly used in the therapy of people living with HIV infection. These drugs are commonly used in combination and act by inhibiting viral protease, blocking viral replication. Adverse drug reactions to protease inhibitors include gastrointestinal problems, rash and metabolic disturbances. The metabolic derangements associated with protease inhibitor therapy are the most problematic adverse events associated with therapy, and vary in incidence from drug to drug. These derangements include hyperlipidemia, abnormal fat distribution (lipodystrophy) and impaired glucose tolerance, which is believed to be due to peripheral insulin resistance. Clinicians caring for patients being treated with protease inhibitors must be vigilant for adverse events, notably those involving altered lipid and glucose metabolism.
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PMID:Adverse drug reactions to protease inhibitors. 1242 51

The use of HIV protease inhibitors (PIs) may be associated with serious adverse side effects that include fat tissue redistribution, hyperlipidemia, and insulin resistance. The etiology of this toxic metabolic syndrome (commonly referred to as 'HIV lipodystrophy syndrome') remains to be elucidated. The interpretation of available clinical data on this subject is complicated in part by the pervasiveness of potential confounding factors that cannot be easily eliminated or adequately controlled. Numerous investigators have examined the effects of PIs on cellular processes in model systems amenable to extensive experimental manipulations; the present review primarily focuses on these efforts. The ultimate goal is the unambiguous identification of discrete cellular targets being surreptitiously impacted by PIs. SREBP and Glut4 are discussed as candidate target molecules in this context. The identification of cellular factors interacting with PIs represents a necessary first step in devising rational strategies for improvement in drug therapy.
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PMID:Investigating the cellular targets of HIV protease inhibitors: implications for metabolic disorders and improvements in drug therapy. 1246 48

Protease inhibitors used as therapy for HIV-1 infection have been associated with metabolic side-effects such as peripheral fat wasting, central adiposity, hyperlipidaemia and insulin resistance. This metabolic disorder is known as the lipodystrophy syndrome. This syndrome can be recognized by the early appearance of an increase in serum triglyceride, cholesterol and plasma-free fatty acid levels. Here, we describe an HIV-1 positive patient with the lipodystrophy syndrome in whom a decline in serum triglycerides was seen along with a significant improvement in glucose uptake following treatment with bezafibrate for 3 months. This improvement may be a consequence of the Randle effect, i.e. increased availability of plasma-free fatty acids is negatively correlated to glucose uptake. We also noted a significant improvement in endothelial-dependent flow-mediated dilatation after treatment with bezafibrate. This effect could result from the increased glucose uptake observed and a decrease in insulin resistance secondary to the lowered triglyceride levels by bezafibrate. We conclude that bezafibrate may be of clinical utility in the lipodystrophy syndrome, through its beneficial effects on insulin resistance, glucose uptake and endothelial dysfunction.
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PMID:Bezafibrate-induced improvement in glucose uptake and endothelial function in protease inhibitor-associated insulin resistance. 1247 19

Osteonecrosis has been increasingly associated with HIV disease throughout the 1990s, and the incidence appears to be rising. The hip is most commonly involved and often bilaterally. Although anecodotal reports suggest an association between osteonecrosis and highly active antiretroviral therapy, controlled epidemiologic studies do not support a direct link. Many patients with osteonecrosis have established risk factors, some of which may be related to HIV disease or its therapy, including corticosteroid use and hyperlipidemia. Alcoholism, hypercoagulability, megesterol acetate use, immune reconstitution, and other factors may also contribute. Plain radiographs and magnetic resonance imaging are the cornerstones of diagnosis. Management is dependent on the stage of bone disease and ranges from observation to total joint arthroplasty. Clinicians may help to prevent HIV-associated osteonecrosis by encouraging patients to limit their exposure to the established risk factors for the disease.
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PMID:Osteonecrosis in HIV disease: epidemiology, etiologies, and clinical management. 1247 64

Protease inhibitors for treatment of HIV-1 have been linked with increased risk of hyperlipidaemia and hyperglycaemia. In a cohort of 5672 outpatients with HIV-1 seen at nine US HIV clinics between January, 1993, and January, 2002, the frequency of myocardial infarctions increased after the introduction of protease inhibitors in 1996 (test for trend, p=0.0125). We noted that 19 of 3247 patients taking, but only two of 2425 who did not take, protease inhibitors had a myocardial infarction (odds ratio 7.1, 95% CI 1.6-44.3; Cox proportional hazards model-adjusted for smoking, sex, age, diabetes, hyperlipidaemia, and hypertension-hazard ratio 6.5, 0.9-47.8). Our findings suggest that, although infrequent, use of protease inhibitors is associated with increased risk of myocardial infarction in patients with HIV-1.
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PMID:Protease inhibitors and cardiovascular outcomes in patients with HIV-1. 1248 Apr 30

Highly active antiretroviral therapy, which includes a combination of protease inhibitors, is highly successful in controlling human immunodeficiency virus (HIV) infection and reducing the morbidity and mortality of autoimmune deficiency syndrome (AIDS). However, the benefits of HIV protease inhibitors are compromised by numerous undesirable side effects. These include peripheral fat wasting and excessive central fat deposition (lipodystrophy), overt hyperlipidemia, and insulin resistance. The mechanism associated with protease inhibitor-induced metabolic abnormalities is multifactorial. One major effect of the protease inhibitor is its suppression of the breakdown of the nuclear form of sterol regulatory element binding proteins (nSREBP) in the liver and adipose tissues. Hepatic accumulation of nSREBP results in increased fatty acid and cholesterol biosynthesis, whereas nSREBP accumulation in adipose tissue causes lipodystrophy, reduces leptin expression, and promotes insulin resistance. The HIV protease inhibitors also suppress proteasome-mediated breakdown of nascent apolipoprotein (apo) B, thus resulting in the overproduction and secretion of triglyceride-rich lipoproteins. Finally, protease inhibitor also suppresses the inhibition of the glucose transporter GLUT-4 activity in adipose and muscle. This latter effect also contributes directly to insulin resistance and diabetes. These adverse effects need to be alleviated for long-term use of protease inhibitor therapy in treatment of HIV infection.
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PMID:Effects of HIV protease inhibitor therapy on lipid metabolism. 1254 52

There is accumulating evidence that human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs) can induce hyperlipidaemia. To evaluate the frequency and type of hyperlipidaemia in PI-treated patients, 98 outpatients were prospectively analysed for their lipoprotein characteristics at the Medizinische Hochschule in Hannover, Germany. Fifty-seven percent of the patients studied presented with hyperlipidaemia. Both hypertrigylceridaemia (type IV and V hyperlipoproteinaemia, 33%) and hypercholesterolaemia (type IIa hyperlipoproteinaemia, 6%) were detectable. The remaining 18% had a type IIb hyperlipoproteinaemia. Increased lipid levels were highly statistically significant compared to a control group of PI-naive HIV-1-infected patients [low-density lipoprotein (LDL) 146 mg/dl (range, 53-274 mg/dl) versus 105 mg/dl (range, 22-188 mg/dl; P=0.0006); very-low-density lipoprotein (VLDL) 35.5 mg/dl (5-253 mg/dl) versus 18 mg/dl (range, 3-94 mg/dl; P=0.0002)]. All PIs used (saquinavir, indinavir, nelfinavir and ritonavir) were associated with this variable form of hyperlipidaemia according to the Fredrickson classification. There was no significant correlation of any determined lipid value with the duration of treatment. A higher frequency of the apolipoprotein E2 allele and E4 allele was observed in the hyperlipidaemic subjects. Patients with excessive hypertriglyceridaemia showed a reduced lipoprotein lipase activity. Lipodystrophy was observed especially in hyperlipidaemic patients and to a lesser extent in normolipidaemic subjects. The frequency of hyperlipidaemic risk factors was surprisingly high in the group studied, which in turn may explain the proposed increased risk of atherogenesis in HIV-1 PI-treated patients. Therefore, PI-treated subjects should also be evaluated for their lipoprotein pattern, which may require antihyperlipidaemic interventions.
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PMID:Lipid evaluation in HIV-1-positive patients treated with protease inhibitors. 1273 56

Fat redistribution (lipodystrophy) and metabolic anomalies are reported increasingly in HIV-infected patients being treated with protease inhibitors. The incidence of these side effects ranges from 5% to 75% in such patients, who often complain of spontaneous fat wasting in the face, arms, or legs, with or without central obesity. Hyperlipidemia and insulin resistance are almost always associated with lipodystrophy. We review the metabolic complications of antiretroviral therapies and discuss possible therapeutic interventions.
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PMID:Metabolic effects of protease inhibitor therapy. 1273 15

The use of anti-retroviral protease inhibitors in combination with nucleoside analog or non nucleoside reverse transcriptase inhibitors (HAART) has led to dramatic decreases in the mortality seen with HIV infected patients. In concert with these treatment regimens, especially with the inclusion of the anti-retroviral protease inhibitors (PI), a complex series of metabolic complications occurred. These included alterations of fat and carbohydrate metabolism. In some patients, one could observe either lipoatrophy (fat wasting) as well as lipohypertrophy (fat deposition) or both. The problem is that the lack of a case definition of the altered fat metabolism confuses diagnoses. In vitro, interference with fat cell differentiation has been demonstrated by PI. Further, in vitro studies demonstrate that indinavir, a PI currently used in HIV treatment, can interact with the insulin responsive glucose transporter (GLUT4). The activity of the GLUT4 is inhibited by indinavir and eventual insulin resistance has been shown (i.e. in vivo and in vitro). Also, controversy exists regarding insulin signaling in fat cells. Finally, the relationships between hyperlipidemia and/or lipolysis and altered carbohydrate metabolism (i.e. mild glucose intolerance, insulin resistance) suggest an association with cardiovascular risk in protease treated patients (Metabolic Syndrome X). In short, while multiple problems exist, no one mechanism can account for the changes observed.
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PMID:Anti-retroviral protease inhibitors--'a two edged sword?'. 1274 88


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