Dapsone, Bactrim, and Lyme Disease: What In Vitro Studies Show
Some antibiotic combinations show activity against Borrelia in culture
Dapsone and sulfa drugs have been studied against stationary-phase organisms
Laboratory findings do not necessarily predict clinical outcomes
Researchers have explored whether combinations of antibiotics may improve activity against stationary-phase Borrelia burgdorferi in laboratory culture models.
Interest in dapsone and Lyme disease increased after investigators identified several sulfa drugs and trimethoprim with activity against persister forms of Borrelia in vitro. However, these findings came from laboratory studies and do not establish effectiveness or safety for routine clinical treatment.
In the study by Feng and colleagues, researchers screened compounds from FDA and National Cancer Institute drug libraries. “Dapsone, sulfachlorpyridazine and trimethoprim showed very similar activity against stationary phase B. burgdorferi enriched in persisters; however, sulfamethoxazole was the least active drug among the three sulfa drugs tested.” [1]
Combinations of antibiotics were more effective in reducing stationary-phase organisms in culture than single-drug approaches alone.
Findings From the In Vitro Study
The investigators reported several observations:
- Sulfa drugs combined with other antibiotics were more active than individual drugs alone;
- Four-drug combinations showed greater activity than three-drug combinations;
- Combinations including dapsone, minocycline, cefuroxime, azithromycin, or rifampin demonstrated the greatest activity among the sulfa-containing regimens studied;
- Daptomycin-containing combinations remained more active than the sulfa-drug combinations.
The authors stressed that these were laboratory findings only and emphasized the need for additional animal and clinical studies.
Dapsone and Bactrim Are Not Standard Lyme Disease Treatments
Patients searching for “Bactrim for Lyme disease” or “dapsone and Lyme disease” may mistakenly assume these medications are standard first-line therapies.
However, doxycycline, amoxicillin, and cefuroxime remain the most commonly recommended antibiotics for early Lyme disease.
Dapsone and trimethoprim-sulfamethoxazole (Bactrim, Septra) are medications used primarily for other conditions and may carry important risks and side effects.
Dapsone has historically been used in combination regimens for leprosy and may cause:
- Hemolysis
- Methemoglobinemia
- Hepatitis
- Cholestatic jaundice
- Rash reactions
Trimethoprim-sulfamethoxazole is commonly marketed under the brand names Bactrim and Septra.
Daptomycin vs Dapsone
The study also evaluated daptomycin-containing combinations.
Daptomycin is an intravenous antibiotic used for serious bacterial infections including bacteremia and endocarditis. It is marketed in the United States under the trade name Cubicin.
Potential side effects may include:
- Muscle injury and rhabdomyolysis
- Eosinophilic pneumonia
- Injection site reactions
- Gastrointestinal symptoms
- Blood pressure abnormalities
Because daptomycin requires intravenous administration and monitoring, it is not routinely used for standard Lyme disease treatment.
Why Persister Studies Matter
Persistent symptoms after Lyme disease treatment remain an area of active research.
Laboratory persister models attempt to better understand why some organisms survive stressful conditions in culture. However, activity against stationary-phase Borrelia in vitro does not necessarily translate into improved patient outcomes.
Additional research is needed to determine which findings are clinically meaningful and which may not apply outside the laboratory setting.
For a broader overview of symptoms, diagnosis, and treatment approaches, visit the Lyme disease symptoms guide.
Frequently Asked Questions
Does Bactrim treat Lyme disease?
Bactrim is not considered a standard first-line treatment for Lyme disease.
What is dapsone used for?
Dapsone is commonly used for leprosy and certain dermatologic or infectious conditions.
What did the study find about dapsone and Lyme disease?
The study found that dapsone-containing combinations showed activity against stationary-phase Borrelia in laboratory culture models.
Does in vitro activity prove a treatment works in patients?
No. Laboratory activity does not necessarily predict safety or effectiveness in human clinical care.
Why are persister studies important?
Persister studies may help researchers better understand bacterial survival mechanisms and ongoing symptoms after infection.
Clinical Takeaway
Laboratory studies suggest that certain antibiotic combinations may show activity against stationary-phase Borrelia in culture.
However, these findings should not be interpreted as proof that dapsone, Bactrim, or daptomycin are standard or universally effective Lyme disease treatments.
Further clinical research is needed before in vitro findings can be translated into routine patient care.
Related Articles
These related articles explore persistent symptoms, co-infections, antibiotic approaches, and challenges in Lyme disease treatment research.
Persistent Lyme Disease
Post-Treatment Lyme Disease Syndrome
Lyme Coinfections
Recovery From Lyme Disease
Delayed Lyme Disease Diagnosis
References
- Feng J, Zhang S, Shi W, Zhang Y. Activity of Sulfa Drugs and Their Combinations against Stationary Phase B. burgdorferi In Vitro. Antibiotics (Basel). 2017;6(1):10.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
Dr. Cameron, my daughter has many symptons of Lyme. She tested and mycoplasma was the only one that showed up from the Lyme test. . She has voice problems, swallowing problems, hair loss, sensory issues like smell is very strong to her, neurological issues make walking difficult, pain, numbness, brain fog, and so on. She never remembers being bitten by a tick. She has tried oral antibiotics but can never stay on them very long. Now she is weaker and feels like her digestive system is slowly shutting down,; swallowing is difficult. Is there anything she could do to build up her immune system before tackling antibiotics again? How difficult is it to do immunoglobulin IVs?
I am sorry to hear your daughter remains ill. It is hard to judge if a mycoplasma is the cause of an illness. It can be difficult to tolerate any treatment. IV antibiotics can also affect the stomach even with probiotics. There may be regimen(s) available if your reach out to your doctor. The alternative medicine field and IVIG have been proposed but it is difficult to evaluate without an one on one assessment. You may also need to make sure you do not have another illness.
I carried both of my children while I had Lyme disease. At the time didn’t know that I had it, but I’m always worried that I’ve passed it on to one or both of them. Every time they complain of any kind of ache I’m worried. I know they have done tests on cadavers with MS, ALS, and I think it was dementia, but when the brain stem was tested they all came back with the Borrelia bacteria. My mother has MS. Do you think it’s possible that she passed this virus onto me? I have never had a tick bite to my knowledge. When my test finally came back positive, I asked my mother if she ever remembers me having a tick as a child. She didn’t. So either I was bitten as a child or I wasn’t bitten at all and it was passed to me. I mean that’s how I see it. What is your opinion?
You have raised questions that are yet to be resolved. It is difficult to study transmission given the extensive exposure in a lifetime.
Dr. Cameron, have any of your patients used the Daptomycin + cefuroxime + doxycycline combination referenced in the article reviewed here? What are the potential downsides/negative side effects in vivo?
I have followed their in vitro results. I have not seen results beyond their cultures. It is unclear if the in vivo results will be as good or if there are any additional side effects in vivo. I have been reluctant to add Daptomycin to the regimen until more information is available.
Is there any specific, combination of antibiotics to treat ALS Lyme? Any other supplements will help for antibiotics resistant patients?
ALS and Lyme disease share some similar characteristics. Any evaluation should also include a neurologist. Any treatment must be individualized.
I did 2 months of iv daptomycine, doxy and oral ceftin because the lyme dr I was seeing said john Hopkins found this to be the cure.
8 months later I’m not better. Was that a waste of time?
I have left that dr and just started seeing a new one who has me in rifampin with supplements because a lot of my symptoms point to bart even though my test was negative. I asked if it should be combined with another antibiotic and she said not at this time.
I was you patient when living in ny . What do you think?
Daptomycin was helpful in the test tube. It still needs more research to determine if it will help in people. It can be difficult to determine who will benefit from additional antibiotics.
Cameron, I am newly diagnosed with Lyme, Bartonella, Mycoplasma and B. Burg. My Lyme Dr. Prescribed me Minocycline, Flagyl, Vibratabs and Valtrex, I am very ery sensitive to alot of medications and honestly I am afraid to take all of these pills. I have started a herbal protocol but it seems as though I am sensitive to some of these as well. Do you have any suggestions?
I typically start slower in patients sensitive to medications. I am curious why you mentioned Minocin and Vibratabs. Vibratabs are brand name doxycycline. I would not prescribe both.
Back in 2016 I had best results with a doxycycline + azithromycin + cefuroxime combination.
I was bit by a black legged tick in the fall 2012 and a black legged tick nymph in 2013. I became ill the first time in three months after the first bite. Never did quite feel well until an extended course of doxycycline, then an extended course of azithromycin added to that, then an extended course of cefuroxime added, all in combination. Took that combination until I presented well.
I find each of the antibiotics you have taken by themselves or in combination helpful for my patients without the treatment proposed in the culture. I also find treatment for Babesia helpful.
Hello dr. Cameron, what do you think about the combination of azithromycin and cefuroxim at the same time for a 10 year old boy with chronic lyme? Thank you!
I have used the combination in a few cases. I still have to individualize treatment and evaluate for other causes