September 29, 2012

Common HIV drug may cause memory loss

Washington, Sept 29, 2012 PTI:

A commonly prescribed drug for HIV patients may lead to memory decline by increasing the risk of damage to nerve cells, a new study by Johns Hopkins has claimed.

Nearly 50 per cent of people infected with HIV will eventually develop some form of brain damage that, while mild, can affect the ability to drive, work or participate in many daily activities, the researchers said.

It has long been assumed that the disease was causing the damage, but Johns Hopkins researchers say the drug ‘efavirenz’ may play a key role.People infected with HIV typically take a cocktail of medications to suppress the virus, and many will take the drugs for decades.

Efavirenz is known to be very good at controlling the virus and is one of the few that crosses the blood-brain barrier and can target potential reservoirs of virus in the brain.

Researchers say more caution is needed because there may be long-term effects of these drugs on the brain.

“People with HIV infections can’t stop taking anti-retroviral drugs. We know what happens then and it’s not good,” said Norman J Haughey, associate professor of neurology at Johns Hopkins University School of Medicine.

“But we need to be very careful about the types of anti-retrovirals we prescribe, and take a closer look at their long-term effects. Drug toxicities could be a major contributing factor to cognitive impairment in patients with HIV,” he said.

Investigators examined the effects of 8-hydroxyefavirenz and other metabolites and found major structural changes when using low levels of the drug, including loss of the important spines of the cells. Haughey and his colleagues found that 8-hydroxyefavirenz is 10 times more toxic to brain cells than the drug itself and, even in low concentrations, causes damage to the dendritic spines of neurons.

In the case of efavirenz, a minor modification in the drug’s structure may be able block its toxic effects but not alter its ability to suppress the virus.


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