Common Allergy Drug Could Kill Lyme Disease

A popular drug that targets allergy symptoms could also kill off Lyme disease germs, a new study suggests.

February 11, 2015

As Lyme disease rates continue to climb in the U.S., there are still major problems with standard diagnosis and treatment. It's estimated that up to 20 percent of people treated with the standard 2- to 4-week antibiotic treatment continue to suffer from fatigue, pain, and other Lyme symptoms. But a new study published in the Open Access publication Drug Design, Development and Therapy suggests a common allergy drug could become an effective Lyme treatment.

A study, funded by the Bay Area Lyme Foundation and conducted by Stanford School of Medicine researchers, shows that loratadine (marketed as Claritin), a common antihistamine frequently taken to treat allergy symptoms, may be able to help kill Borrelia burgdorferi, the bacteria associated with Lyme disease that's often transmitted by ticks.


"Our results bring us closer to the possibility of discovering the first targeted therapy to treat Lyme disease," says Jayakumar Rajadas, PhD, Director of the Biomaterials and Advanced Drug Delivery Lab (BioADD), Stanford School of Medicine, and lead author of the study. "It's exciting to see first-hand that our insights into the metabolic activity of this elusive bacteria may give us the ability to actually kill it."

The results of this new laboratory study show that loratadine and specifically its metabolite, desloratadine, are able to prevent manganese (Mn) from entering the cell wall of the bacteria that causes Lyme disease, starving the bacteria and causing it to die in test tubes.  The antihistamine accomplishes this by inhibiting the bacteria's transport system.

Manganese is required for certain metabolic processes of Borrelia burgdorferi and also plays an important role in numerous biological processes in the human body.  Previous research shows that in general, bacteria scavenge the body for trace metals that circulate in the blood and have developed special adaptations on their cell walls to internalize these metals. Lyme transport protein important to Lyme germs, BmtA, binds with manganese to bring it into the bacteria, and studies have shown that BmtA and manganese are required to make the bacteria harmful to the human body.

"Because current treatments do not work for everyone and the bacteria that causes Lyme disease offers many treatment challenges, this study offers encouraging insights for researchers, and hope for the 80 million Americans at risk of getting Lyme disease," says Bonnie Crater, founder and science committee chairperson at the  Bay Area Lyme Foundation, the leading private funder of innovative Lyme disease research in the country.  "We are grateful to the BioADD team for their commitment to finding solutions to this difficult disease.