Link between HIV drugs and heart attack

A study by Sydney researchers showing that the protease inhibitor type of HIV drugs carry a greater risk of heart attack than the new integrase inhibitor family of drugs is expected to lead to a greater understanding of the disease and how to treat it.

Associate Professor Katherine Samaras and Professor Andrew Carr at the Garvan Institute of Medical Research and St. Vincent’s Hospital looked at the effects on blood fat metabolism of two HIV drugs; ritonavir, a protease inhibitor marketed by Abbott Laboratories as Norvir and Merck's new integrase inhibitor drug Raltegravir.

Ritonavir has been linked to numerous metabolic complications including higher fasting levels of cholesterol, while Raltegravir is known to have fewer metabolic effects.

The study involved 20 people, one half taking ritonavir and the other Raltegravir, who were measured after eating for different blood fat levels; a key indicator of heart attack risk. The researchers found that after one month, ritonavir caused “significantly higher” levels of the atherosclerosis-inducing LDL cholesterol after a meal, compared to raltegravir.

A unique aspect of the study was that it involved people without the HIV infection, allowing the researchers to more clearly ascertain the effects of the drugs without interference with other medications or the disease itself.

“While a few other studies have investigated post-meal blood fat and sugar metabolism, this is the most comprehensive study of the post-meal metabolic response with these medications to-date,´ said Associate Professor Samaras.

“About half the heart risk of protease inhibitor therapy has never been explained. Our findings of higher post-meal LDL cholesterol after food may explain at least some of this missing link in accelerated heart risk.”

The results represent an important step towards improving the health and quality of life of HIV sufferers.

“Our data may explain why patients receiving protease inhibitors have rates of heart attack that are higher than estimates derived from conventional heart disease risk calculators, which only use fasting cholesterol values,” said Professor Carr

“HIV patients may therefore need more aggressive management of heart disease risk than previously appreciated.”