Washington :Drugs for Alzheimer's disease currently undergoing clinical trials may have adverse side-effects, warns a new study.

The drugs could act like a bad electrician, causing neurons (nerve cells) to be miswired and tripping their ability to message the brain, suggests the study.

"Let's proceed with caution," said Robert Vassar, professor of cell and molecular biology at Feinberg School of Medicine, who led the study conducted on mice, the journal Molecular Neurodegeneration reports.

"We have to keep our eyes open for potential side effects of these drugs." Ironically, the drugs could impair memory, said Vassar, according to a Feinberg statement.

The drugs are designed to inhibit BACE1, the enzyme Vassar originally discovered that promotes the development of the clumps of plaque that characterise Alzheimer's.

BACE1 acts as a molecular scissors, cutting up and releasing proteins that form the plaques. Thus, drug developers believed blocking the enzyme might slow the disease.

But in Vassar's new study, he found BACE1 also has a critical role as the brain's electrician. The enzyme maps out the location of axons, the wires that connect neurons to the brain and the rest of the nervous system.

Working with mice from which BACE1 was genetically removed, Vassar discovered their sense of smell was incorrectly wired.

"It's like a badly wired house," Vassar said. "If the electrician doesn't get the wiring pattern correct, your lights won't turn on and the outlets won't work."

These findings were presented at the 2012 annual meeting for the American Association for the Advancement of Science, Vancouver, Canada.