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Common Allergy Medication May Be Effective In Starving and Killing the Bacteria That Causes Lyme Disease According to New Study

Study Offers Insights Into Metabolic Activity of Borrelia burgdorferi and May Lead to First Targeted Therapy for Lyme Disease

Portola Valley, CA — A new study funded by the Bay Area Lyme Foundation and conducted by Stanford School of Medicine researchers shows that loratadine, which is a common antihistamine frequently taken to treat allergy symptoms, may be able to help kill Borrelia burgdorferi, the bacteria associated with Lyme disease. Lyme disease is a potentially debilitating condition with 300,000 new cases in the US each year. The study was published in the Open Access publication Drug Design, Development and Therapy.

“Our results bring us closer to the possibility of discovering the first targeted therapy to treat Lyme disease,” says Jayakumar Rajadas, PhD, Director, 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 (trade name: Claritin®) 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, BmtA (Borrelia metal transporter A).

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. These adaptations are called transport proteins, and BmtA is the specialized transport protein for Borrelia burgdorferi. 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.[i]

“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,” Bonnie Crater, founder and Science Committee Chairperson, Bay Area Lyme Foundation, the leading private funder of innovative Lyme disease research in the US. “We are grateful to the BioADD team for their commitment to finding solutions to this difficult disease.”

Currently, patients with Lyme disease are typically prescribed a 2–4 week course of antibiotics, but approximately 10 to 20% of patients treated with this regimen will have lingering symptoms of fatigue, pain, or joint and muscle aches[ii].

About Lyme Disease

Increasing in threat due to rising prevalence across the US, Lyme disease is a potentially debilitating infection caused by bacteria transmitted through the bite of an infected tick to people and pets. If caught early, most cases of Lyme disease can be effectively treated, but it is commonly misdiagnosed due to lack of awareness and unreliable diagnostic tests. There are about 300,000 new cases of Lyme disease each year, 10 times more than previously reported, according to statistics released in 2013 by the CDC. As a result of the difficulty in diagnosing and treating Lyme disease, as many as one million Americans may be suffering from the impact of its debilitating long-term symptoms and complications, according to Bay Area Lyme Foundation estimates.

About Bay Area Lyme Foundation

Bay Area Lyme Foundation, a national nonprofit organization committed to making Lyme disease easy to diagnose and simple to cure, is the leading funder of innovative Lyme disease research in the US.  A national 501(c)3 nonprofit organization based in Silicon Valley, the Foundation collaborates with world-class scientists and institutions to accelerate medical breakthroughs for Lyme disease. It is also dedicated to providing reliable, fact-based information so that prevention and the importance of early treatment are common knowledge. For more information about Lyme disease or to get involved, visit or call us at 650-530-2439.

To access the publication, click here.


[i] Ouyang Z. et. al.: A manganese transporter, BB0219 (BmtA), is required for virulence by the Lyme disease spirochete, Borrelia burgdorferi. Proc Natl Acad Sci USA, 2009 Mar 3;106(9):3449-54.

[ii] Wormser G.P., et. al..: Duration of antibiotic therapy for early Lyme disease. A randomized, double-blind, placebo-controlled trial. Ann Intern Med, 2003 May 6;138(9):697-704.

59 Comments on “Common Allergy Medication May Be Effective In Starving and Killing the Bacteria That Causes Lyme Disease

  1. Want to hear something interesting? Jewelers and potters listen up! I had to stop pottery and jewelry-making because the white fireproof blocks used in the kilns and soldering stations are made out of manganese, which I found out releases manganese gas, which is much way more bio-available for bacteria than the manganese you get through diet. A possible low-grade infection, plus toxic mold from the pottery studio, plus the manganese gas made my health plummet. Through my two-year search of trying to find out what was wrong with my health, I came across a story of a woman who did pottery in her home and how it made her sick she had suspected the manganese gas had something to do with it. Smart lady.

    1. Hi Devon, I suspect that you don’t have this right. Refractory materials are largely magnesite, not manganese. In fact, manufacturers go to great lengths to make sure there is NO manganese in the compound as manganese (and iron) cause premature failure of the refractory material. Secondly, refractory materials are chosen because of their resistance to gassification. If there is a gaseous component causing problems, it is most unlikely to be coming from the refractory.

  2. I was just diagnosed with Lyme disease this week, will any of these medications help me…I have had this since 2009, just started the antibiotics for a month?

    1. I am afraid Bay Area Lyme is not a clinical organization and can not comment on individual cases or treatments. We would advise you to speak with your doctor and/or consult the ILADS directory for a physician referral. We wish you the best of health!!

  3. CC won’t do anything, trust me.. I went there too and it was a waste of money .. we need an update on when we can expect the trial to begin., any word?

    1. We empathize strongly. The Bay Area Lyme-funded Clinical Trial is still in development and a large number of researchers convened at a summit just a few weeks ago to expand on the scope and protocols of this study. An update will be published soon. Unfortunately with a study of this nature there are a lot of administrative hurdles to go through before the study can commence. Thank you for your interest and your patience. There is more information on the Clinical Trial page, including how you can register to be considered for this study.

    1. Hi Ronald, Loratadine (and desloratadine) are considered “second generation antihistamines,” and generally believed to not cross the blood-brain barrier or impact the central nervous system, particularly at manufacturer-recommended doses. However, there does seem to be some evidence of dose-related CNS effects at higher levels (see article in the British Medical Journal here) and these medicines can cause a wide range of lesser symptoms including headaches, sleepiness or drowsiness, fatigue, nervousness, stomach pain, diarrhea, dry mouth, sore throat, eye redness, blurred vision, nosebleeds, or rashes. In addition, other infections — including Lyme — can weaken the barrier, increasing the probability of certain types of molecules permeating. Do talk to your doctor about any medications before starting treatment.

    2. It solved hand and foot pain in 1 month for a friend of mine and steadily after cleared her mind! I’m taking 2-3 per day starting yesterday. I’m thinking it’s worth a try. She heard this from a leading LD Dr from Columbia, Mo

  4. My Dr. put me on Claritin a year and a half ago when I felt creeping signs of relapse, as I have had Lyme for about 35 years. Around horses in the NE we have lots of ticks. Since taking the Claritin, all symptoms disappeared and I have felt fine. I try and keep very healthy with several supplements like Olive leaf extract (anti viral/bacterial), multi, Ashwagandha (strengthen immune) and CoQ10. I am 69 yrs old. I have had two bad relapses over the years and had to go on Doxy for 6 weeks. Don’t ignore symptons, they just get worse!! My Dr. said just say on Claritin.

    1. Dear Jacqueline, I was just diagnosed with chronic late stage Lyme by Dr from the Cleveland Clinic (“CDC” approved however they will not treat it as an institution). My story reads like most, but add Toxic Mold and then leaving our home of 31 years and it sent my body over the edge. I am currently beginning treatment, mostly to correct vitamin & mineral deficiency plus gut support, from Functional Medicine (Cleveland Clinic) and doxycycline from my family doctor. I would be very grateful if you could share the dosage of Claritin and times you take it. I need to get this under control. I’m 57 years old time is not on my side. God Bless and much thanks!

  5. Is the loratadine being studied/used to combat the coinfections of lyme as well? Bartonella, mycoplasma, etc.? Have you seen any results with loratadine on these coinfections?

    1. Hi Danielle, Thank you for the comment. Loratadine was shown to block the activity of BmtA. BmtA is a metal transporter protein which transports manganese from the environment (the tick, animal reservoir, or the human) to the inside of the bacteria, hence its promise for combatting Lyme. Because most bacteria use iron and not manganese, BmtA is not found in other bacteria (and other co-infections) and thus loratadine would not likely be of help in fighting other co infections.

  6. I have been diagnosed positive for Lyme disease four (4) separate times and given Doxycycline for various lengths each time. Besides a couple of bullseyes, great redness, and terrible itching, there have been no other symptoms. But now I am wondering. I have been having ever-increasing balance problems since first diagnosed 10 to 15 years ago. Could there be any relationship? I now have to use two walking sticks to get around.

    1. Dear Biz, Bay Area Lyme is not a clinical organization and cannot provide individual medical guidance or diagnosis, however, a bullseye is a definitive symptom for Lyme disease and balance, joint, muscle, or nerve issues are common symptoms of late-stage Lyme. It is also true that antibiotics have to be taken for a minimum duration to have impact; shorter treatment cycles may not be sufficient to fully eliminate the bacteria. We would encourage you to speak with your medical care provider in more detail about your symptoms and treatment options and wish you full health. We would also encourage a trip to a neurologist that is familiar with Lyme disease. The ILADS (International Lyme and Associated Diseases Society) website can help with doctor referrals, based on your geographic location. Best wishes.

    2. It was when I [treated] myself with Ivermectin that my balance problems and pain diminished greatly. There is often a parasite besides bacteria of micro filaria that infect the brain and CNS…. look it up! After using Loratadine for a month I note my mind is clearer and I have better energy and a lot less pain overall! Great research! Thanks for all who care and help!

  7. Was any consideration given to the idea that taking Claritin for seasonal allergies could mask Lyme symptoms? My Dr. has had me take Claritin from first thaw through first frost for two years now. This past summer I had neck stiffness, different joint issues, etc, but it wasn’t until I stopped taking it that everything seemed to balloon into more noticable symptoms. I’m often in tick areas but thought I used pretty good prevention methods – now I’m wondering if I missed something!

    1. Thank you for the question. Unfortunately it is true that many treatments (antibiotics, NSAIDS, etc.) will mask symptoms and clinicians need to carefully weigh many factors when determining individual treatments. We still need to prove that loratadine could be effective in treating Lyme disease in patients. One would certainly hope that doctors would take all relevant information into consideration when assessing symptoms for Lyme disease, e.g., in patients taking loratadine OTC. It is always important to seek help if you continue to experience symptoms. We wish you good luck and good health!

  8. Four weeks into Clarinex (desloratadine) after 18 months of failed treatment. 10 microscope photos a day showing clearance accelerating after 3 weeks! 10mg/day. Sleeping for the first time since 2010. Planktonic still lingering, but less every day.

    1. From Wendy Adams, Program Advisor and Advisory Board Member, Bay Area Lyme Foundation:
      Thanks for the question. Cystic forms were not studied here. The role of BmtA in cyst forms is not well understood, as BmtA has not been widely studied and was only characterized in 2008. It’s not clear if the assays used would work with cystic forms, as they measure ATP to determine cell killing and because cystic forms may have altered growth and metabolism, measuring ATP might not be appropriate to determine efficacy of desloratadine on those forms.

    2. It is believed that Borrelia burgdorferi can transform into a cyst when threatened (e.g., by antibiotics or the immune system). We don’t know much about how they act in the body, however, it has been shown in some research that the bacteria will return to its spirochetal form once the threat subsides and resume its attack on the host (perhaps appearing as a “relapse” of the infection.)

      It is important to note, however, that a bacterial cyst is formed by a single bacteria and is microscopic, thus not visible to the naked eye. They are not the same as skin cysts that can develop from a wide array of conditions including infection, clogged glands or follicles, etc.

  9. I wonder if it would work in synergy with resveratrol?

    If Mn is taken up by the mitochondria -> oxidative phosphorylation inhibited, does this -> mitophagy and then horizontal transfer of mtDNA from “donor cells” helps to keep the infected cell viable?

    When mitophagy happens, is Mn (and some proteins) then available for Bb to use?

    1. From Jerome Bouquet, PhD, University of California, San Francisco

      Loratadine blocks the intakes of Mn by Borrelia in vitro by blocking its membrane Mn transporter. In the human body, loratadine binds to histamine receptors, unrelated to Mn or mitochondrial functions. There is no reason to believe that Desloradine/loratadine would trigger mitochondrial dysfunction in human cells. Bioavailibity of Mn in the body is basically the same wether you are infected by Borrelia. Mn acts an antioxidant in mitochondria, so even if starving Borrelia off Mn would make a difference in local concentrations of Mn (doubtful), it would have a protective effect rather than trigger mitophagy. Also, oxidative stress tends to kill cells rather than trigger regeneration. Horizontal transfer of mtDNA in human cells is a very recent concept and very little is known, so far it can only be described as tumor cell mechanism.

      A lot is left to understand about the involvement of mitochondrial dysfunction in Lyme disease and chronic Lyme disease. Resveratrol is a supplement reported to improve mitochondrial function as well as several other health effects (tumor suppression, cardiovascular protection,…) However, its effects as a potent drug remains to be demonstrated. Most vitamins and supplements are good for you in the long term at reasonable dosage, but it is all part of a good diverse diet. Antioxidants might be associated with reduced risks of developing an oxidative stress-related disease at some point in life, but it does not mean that they are efficient at treating a specific disease when it occurs.

  10. About 2 years ago I was being bitten by ticks which left a bullseye on the skin where the bite occurred. While at the dr office for my flu shot, I mentioned the bites to him and inquired about Lyme. He said he would prescribe antibiotics because that’s how Lyme is treated. Last winter I came down with pneumonia. Everything the dr prescribed appeared to give me hives. By process of elimination I’ve discovered I’ve been become allergic to beef. The more I eat the more I itch all over, starting on my face and around my mouth. Is there anything I can take to help and will it include all red meats like venison?

    1. We are very sorry to hear about your Lyme disease and the hives. Sounds frustrating! Bay Area Lyme is not a clinical organization and unfortunately can not advise about specific medical conditions. We would suggest that you speak to your health care providers and can also offer referrals for doctors that are familiar with Lyme disease if you would like to consult another doctor. Best wishes, BAL team

    2. I also became severely allergic to beef when I got Lyme disease. Maybe there is some protein in Borrelia burgdorferi that resembles a beef protein?

    3. Hives all over from eating red meat — a juicy, organic, steak from a local farmer. Nice Meat! Except the tick bite I got was the trigger for Alpha Gal. Took 3 steaks in 1.5 months to figure the steak and hives I got 5 hours later were related. There is an AlphaGal site on facebook and it’s growing every day. Sad but true and no cure except to not eat red meat or anything made with it. Luckily I can eat bacon and a little pork without a reaction.

    4. you have probably been bitten by the lone star tick. It causes that allergy to red meat . Google it for more info.

    5. In Australia on the coastal areas around Sydney, it has become a problem with people who have been bitten by ticks.They have all become allergic to red meat. Haven’t heard of a cure yet.

    6. Manganese is necessary in the formation of arginase, which breaks down arginine. In the absence of arginase, arginine builds in the body. Red meat is a high-arginine food, so possibly your reaction is stemming from a manganese deficiency and arginine excess. Other high-arginine foods are chocolate, corn, beans, cheese, and nuts.

  11. Hi,

    I was diagnosed with Lyme. It’s been 4-months that the bullseye rash first showed up and started spreading across my thigh. Never had any symptoms or itch with the rash. It’s starting to disappear. I have stiff neck but not any of the major symptoms of Lyme. It is confusing, the doctor said he needed no tests, it is Lyme. Didn’t explain anything to me. I did my research and now I’m very scared from all I read about Lyme. I was prescribed with an antihistamine (bilastine, approved in Europe with similar effects to desloratadine in US) and cream to put on the rash. I have no idea what to think of this. Diagnose after 3.5 months is early enough? I had almost no symptoms, just stiff neck, the rash, some flu -like symptoms, but no fever, only some indisposition. GERD showed up too.


  12. I have Lyme disease, Cat Scratch Fever, and Babesia. One of the worst symptoms I used to get were sudden attacks of almost seizures (very severe body tremors but I’d stay conscious), very severe sweating, and sometimes torturous nerve pain at the bottom of my left rib cage. My Lyme doctor did at first suggest Claritin, but it didn’t work. The only thing that did work, and almost immediately, was Benedryl IM shots. It was only a temporary solution, but a much needed one, since the attacks were literally torturous. Ultimately, the attacks lessened and then disappeared after many months of IV antibiotics and herbal treatments. I was almost cured last year, but for reasons that are too complicated to state here, the Lyme part of the triple infection is acting up again now.

  13. My Doctor advised me to take Claritin…

    I had the bullseye rash last fall and thought that it was ringworm from my new roommates dog (who loves to roll in the grass). My pharmacist suggested a cream for it (the ignorance about Lyme is sometimes astounding!) …

    I did not have symptoms until April 13, 2015 when my body crashed for four days. It was the worst “flu” that i had ever experienced… I kept trying to get back to normal, but it just wasn’t happening. I am still not up to par… BUT… the Claritin made a BIG difference for me. I am learning to pace myself while I am dealing with this “new normal” because I can get knocked down fairly easy. A trip to the grocery store requires me to lay down when I get back home… but without the Claritin I could barely function at all!

    I am surprised to see this article because I thought it was odd that my Doc wanted me to take Claritin! And now I am feeling very hopeful that there is evidence that what I am doing is the right thing for now. I think my Doc is really on to something here!

    1. Ana, can you please tell me how much Claritin per day does your Doc prescribe ?

    2. Please note: We would advise that you contact your own physician for any clinical recommendations. Bay Area Lyme Foundation is not a medical authority and does not advocate or offer treatment advice.

    1. Thank you for your interest. The clinical trial is currently under internal review at Stanford. We are continuing to collect information from patients interested in the study which will be passed onto the researchers when they formally commence patient recruitment. Please see the Patient Recruitment page if interested. We will update the website as soon as more information becomes publicly available. Potential participants will be contacted directly. We are also continuing to raise funds to support the trial and continuation of this research. Contact our development office for more information. Thank you!

  14. On page 813 of the article the authors state: “Desloratadine exhibited potent borreliacidal activity in vitro at and above 78 μg/mL (250 μM). Currently, desloratadine is prescribed at 5–10 mg dose. A 250 μM dose would roughly translate into 400 mg/day. The mean plasma concentration of desloratadine in human blood after 5 mg or even up to 40 mg dose is about 2–5 ng/mL. Thus, achieving borreliacidal concentrations of desloratadine in blood are challenging”.

    This [research] is a laboratory study whose findings may one day lead to animal or human studies wherein desloratidine or a similar compound can be used at doses that are smaller and thus more viable for the human body – and realistic for the everyday person to use.

    It is an important advancement that needs to be carefully studied but just don’t rush out and buy the antihistamine – you’d be wasting your money.

    I have Lyme and I am a health care researcher.

  15. Fascinating article! I’ve had 3 bullseye rashes and many deer tick bites and now ache all over. I’m 69 and in fairly decent health and I’m wondering if this new discovery might work for me. What were the doses and how long was the course of treatment?

    1. Thank you for your comment. The published study was a laboratory research project, not a clinical trial, so the research does not encompass specific treatment regimens or dosages. Further research will be required to develop a modified derivative that increases the borrecidal efficacy. Bay Area Lyme Foundation is supporting a clinical trial of a combination therapy building on these research findings that is still in development. If you have interest in that study, please click here.

  16. Article by Wagh et. al. stresses desloratadine and not loratadine. The former is Clarinex, versus the latter which is Claritin. Realizing that desloratadine is a metabolite of loratadine, a real question is whether or not those in clinical practice should use Clarinex rather than Claritin in an attempt to synergize, perhaps, with doxycycline to eradicate lyme disease. The various internet items on Wagh et. al.’s findings focus on loratadine where the actual article’s main focus is desloratadine.

    1. Thanks for your inquiry. As you mention, loratadine is metabolized to desloratadine in the body, and that’s why desloratadine was studied. Loratadine is used more often clinically because it is available over the counter in the US. In contrast, desloratadine is available in some other countries OTC (but not in the US). Desloratadine is sometimes prescribed for patients who experience side effects from loratadine. We can’t opine on what clinicians should use because it would really depend on an individual patient’s case. In a clinical study, it may be best to use loratadine because it’s available OTC and therefore will be 1) regarded as more safe and 2) could cost less to manufacture for clinical trial material than desloratadine.

    2. Desloratadine is a prescription-only medicine here in the US though it is available over-the-counter (OTC) in some countries. Loratadine, a more common treatment that is available OTC here in the US, is metabolized to desloratadine in the body, and that is why desloratadine was studied in this reasearch. Desloratadine is sometimes prescribed for patients who experience side effects from loratadine. Your doctor is best equipped to determine which is the right treatment and we would recommend you speaking with your doctor or even sharing the study with him / her for their counsel.

  17. My father has late-stage Lyme disease. I’m wondering if you know how much Claritin is needed to make a difference? Thank you.

    1. Thank you for your comment. The published study was a laboratory research project, not a clinical trial, so the researchers are not advocating specific treatment regimens or dosages. Bay Area Lyme Foundation is supporting a clinical trial of a combination therapy building on these research findings. If you have interest in that study, please click here.

    2. Melittin found in honey bee venom and Stevia whole leaf extract can also help kill Borrelia. Do an Internet search on both.

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