More CD4 cells with d4T versus AZT combo

Researchers at the University of Alabama reported at the Chicago conference that they believe triple-drug therapies using d4T may have an advantage over similar therapies using AZT.

AZT and d4T are two of the five nucleoside analogues approved thus far by the Food and Drug Administration. But AZT and d4T are different than the other three "nukes" in that these two tend to attack virus in the immune system’s active cells while the other three tend to attack virus in the system’s resting cells. Most triple-drug therapies with a combination that attacks the virus in a variety of places in the body and in its replication process. Thus, most triple-drug therapies tend to include either AZT or d4T.

According to the report in Chicago Feb. 3, the "first ever head-to-head" comparisons of AZT versus d4T combinations showed that the two drugs are "equivalent" in their abilities to attack the virus and "should both be considered first-line" options for treatment combinations. But according to Alabama researcher Kathleen Squires, the study of more than 500 patients on one of the triple-drug therapies (which also included the "resting cell nuke" 3TC and the protease inhibitor indinavir) for almost a year showed that d4T to produce a slightly greater viral load drop (1.95 versus 1.60) and a slightly greater CD4 increase (173 versus 141). The AZT combo also resulted in more "minor" gastrointestinal side effects.

A second study, presented by the University of North Carolina-Chapel Hill in a poster Feb. 3, also compared the two combinations. In the second study, involving 100 patients, the researchers found that the viral load drops produced by the two triple-drug combinations were nearly identical (1.64 versus 1.68). But the CD4 counts were again greater in the d4T group (211 versus 139).

A glass of grapefruit juice can help the body absorb several common medicines, including blood pressure reducers, sedatives and the protease inhibitors used to treat AIDS, researchers reported Wednesday.

The "grapefruit juice effect" was discovered by accident nearly a decade ago when scientists gave volunteers grapefruit juice to hide the taste of oral medications, but the latest research determined how it works.

Grapefruit juice decreases the amount of an enzyme present in the small intestine, researchers at the University of Michigan reported in the Journal of Clinical Investigation.

This determination narrowed the search for the ingredient in grapefruit juice that affects drug metabolism, according to the National Institutes of Health, which supported the research.

The grapefruit juice effect applies to all the calcium channel blockers used to lower blood pressure as well as immunosuppressants, sedatives and the protease inhibitors used to control AIDS, NIH said in a statement.

Protease Inhibitors Warning

NewsPlanet Staff

Thursday, June 12, 1997 / 11:29 AM

SUMMARY: Heads up! The FDA has found a not so sweet side effect of the "miraculous" protease inhibitors -- increased blood sugar levels -- and it could be life-threatening.

The U.S. Food & Drug Administration (FDA) issued a warning June 11 that protease inhibitors, the "miracle" AIDS treatment, may pose an increased risk for contracting or aggravating diabetes and hyperglycemia (increased blood sugar levels). While there was no recommendation to stop taking the drugs, the FDA urged physicians to carefully monitor blood glucose levels, and urged those taking the drugs to advise their doctors immediately if they begin to experience increased thirst, increased urination, dry and itchy skin, fatigue, or unexplained weight loss. If the problems are detected early, they can be controlled by oral medications or by insulin injections.

A sudden blood sugar increase may occur in as many as 1% of those taking protease inhibitors, regardless of which brand they use. The increase may occur as early as 4 days after beginning protease inhibitor treatment, but on the average occurs after about 10 weeks. There is no theory yet for the mechanism by which protease inhibitors might be contributing to those problems.

The FDA made its announcement based on reports of 83 people with increased blood sugar levels which were life-threatening in 6 cases and required hospitalization in 21 cases. Half of those people had to stop taking protease inhibitors. An estimated 150,000 in the U.S. are now taking one of the four approved protease inhibitors: Merck & Co's Crixivan (indinavir), Hoffmann-La Roche's Invirase (saquinavir), Abbott Laboratories' Norvir (ritonavir) and Agouron Pharmaceuticals' Viracept (nelfinavir). The FDA is altering labelling requirements for protease inhibitors to include the blood sugar warning, and will be issuing extensive new guidelines for drug treatments for AIDS in the coming week.

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