December 13, 2006

Drug Combo for High Cholesterol

(AIDSmeds.com)—Results of a Spanish study suggest that combining Zetia® (ezetimibe) with a commonly prescribed statin is an effective option for HIV-positive people unable to control their cholesterol levels while receiving a statin alone. Data from the small six-month clinical trial, published in the November 15 issue of AIDS, also indicate that Zetia and Pravachol® (pravastatin) used together are well tolerated and lack negative interactions with medications used to treat HIV.

Unlike statins (HMG-CoA reductase inhibitors), designed to block the action of an enzyme in the liver responsible for producing cholesterol, Zetia inhibits absorption of cholesterol by the intestine (duodenum). In clinical trials involving HIV-negative volunteers, Zetia was found to reduce "bad" LDL cholesterol by 20% when used without other lipid-lower medications. When combined with a statin, Zetia has been shown to reduce LDL cholesterol levels by up to 50%.

For the treatment of elevated cholesterol in HIV-positive people – a problem associated with the use of HIV medications, notably protease inhibitors (PIs) – treatment with the statins Pravachol, Lescol® (fluvastatin), and Lipitor® (atorvastatin) is considered standard. Zocor® (simvastatin) and Mevacor® (lovastatin) are not recommended due to negative interactions with PIs and non-nucleoside reverse transcriptase inhibitors (NNRTIs).

Unfortunately, studies have demonstrated that statins have a limited effect on antiretroviral-associated cholesterol increases. In one study, total cholesterol and LDL cholesterol levels were reduced by just 25% – not nearly enough to push these levels within the normal range.

Based on these lackluster results, a Spanish team studied the addition of Zetia in 18 HIV-positive patients with high LDL cholesterol levels (130 mg/dL or higher), despite the use of Pravachol. All patients were given Zetia (10 mg/day), which they combined with their Pravachol (20 mg/day) and continued on their pre-study HIV drug regimen.

After 24 weeks, 61% of the patients achieved the goal of the study – the reduction of LDL cholesterol to below 130 mg/dL. At the start of the study, the average LDL cholesterol level was 145 mg/dL; after six months, the average LDL cholesterol level was reduced to approximately 122 mg/dL.

Total cholesterol levels – averaging approximately 232 mg/dL at study entry – significantly dropped as well. After 24 weeks, the average total cholesterol level was 209 mg/dL. Significant increases in "good" HDL cholesterol were also reported.

The combination of Zetia and Pravachol was well tolerated in all patients. No patients discontinued therapy due to side effects. The researchers also reported that the addition of Zetia did not affect blood concentrations of the HIV medications used by patients in the study, nor did Zetia blood concentrations deviate from normal when added to patients' existing drug regimens.

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