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CATIE-News: Bite-sized HIV/AIDS news bulletinsSome good news about atazanavir and lopinavir-ritonavirAs mentioned in the two previous CATIE News stories, cardiovascular disease (CVD) is a health concern for HIV positive people, particularly as they age and use medications that may inadvertently increase their CVD risk. Researchers have found that an older and seldom-used anti-HIV drug called indinavir (Crixivan) caused unfavourable changes to the lining of blood vessels and affected blood sugar and insulin levels. All of these changes, if sustained, increase the risk for CVD. Because indinavir belongs to a family of drugs called protease inhibitors (PIs), some doctors suspect that all other PIs may cause similar problems. A general trend is that newer anti-HIV medications appear to be generally safer than other anti-HIV medications that were developed in the late 1980s or early 1990s. To investigate the safety of newer protease inhibitors, a team of researchers in Indiana tested the two most commonly used PIs in the U.S. and Canada:
They enrolled healthy, HIV negative people for these experiments. The reason they used HIV negative volunteers was to eliminate any effect HIV might have had on the experiment. Their results suggest that neither study drug causes endothelial dysfunction and insulin resistance, at least in the short-term—in men. These results, while promising, need to be put into the context of HIV treatment, so please continue reading. Study detailsThe study team recruited 30 participants, all of whom were male. The average age was 37 years. The researchers stated that they did screen potential female volunteers for the study but none of the women had the level of body fat that was necessary for entering the study. This was a double-blind, placebo-controlled trial. Participants were randomly assigned to one of the following groups, or study arms:
Both drugs and placebo were taken for a total of four weeks. Analysis of blood samples and other assessments were done before, during and after the study. In particular, researchers focused on assessing the flow of blood in the arteries of the leg after stimulation with certain drugs. This was an invasive and well-accepted way of finding out about blood flow. Additionally, infusions of insulin and glucose were given to help estimate insulin resistance and its effect on blood flow. ResultsAfter four weeks exposure to the study drugs, the team found the following:
Results—side effectsSide effects reported in this study were not severe and included the following:
Key points1. The findings from this study suggest that over the short-term neither atazanavir nor lopinavir-ritonavir negatively affect blood flow and pressure. Equally important, these drugs do not trigger the development of insulin resistance. 2. Another conclusion is that PIs as a group do not cause endothelial dysfunction or insulin resistance. Rather, if these do occur, they are individual drug effects. Indeed, a recent large European analysis suggests that the use of thymidine analogues (d4T and to a lesser extent ddI and AZT) is associated with the development of diabetes in some HAART users. 3. Atazanavir is sometimes used together with a small dose of ritonavir, usually 100 mg. This combination should not have any different results than seen with atazanavir alone when it comes to endothelial dysfunction and insulin resistance, as even higher doses of ritonavir (200 mg/day) are used with the standard adult dose of lopinavir-ritonavir and these problems were not detected (M Dubé, MD, personal communication). 4. The use of PIs may still carry some unknown or poorly understood CVD risk. For instance, there are hints that in some people who use PIs there may the possibility of an increased risk for blood clots. But this has to be more thoroughly studied and other interfering factors first excluded before firm conclusions can be drawn. 5. If PIs have no additional CVD risk, then it is important to bear in mind that they are supposed to be taken with other agents, usually nukes. It is possible that some nukes may increase the potential for CVD risk. This potential exists for d4T and to a lesser extent ddI and AZT. This risk arises because long-term use of these drugs may be linked to the development of diabetes, which adds to CVD risk. The drug d4T can also raise lipid levels and damage fat cells. Beyond HAARTReducing CVD risk is a lifelong activity and appears to be necessary even for HIV positive people who are not taking HAART. This is because HIV infection appears to cause inflammation and age blood vessels. There are many steps that people can take to reduce their risk of CVD. The following points are meant to serve as a starting point for discussion with health care providers about ways to help reduce CVD risk:
And don’t forget to have a look at our popular new Practical Guide to Nutrition for People Living with HIV at: http://www.catie.ca/ng_e.nsf/table+of+contents AppreciationWe would like to thank Michal Odermarsky, MD (Lund University, Sweden), for his expert review of this article.
—Sean R. Hosein REFERENCES:
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Created on: 08/07/2008 |
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Decisions about particular medical treatments should always be made in consultation with a qualified medical practitioner who is knowledgeable about HIV-related illness and the treatments in question. MORE | |