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Good Advice on Lupus and Bactrim [per sulfa antibiotic research]

Lupus and Bactrim: List sulfa antibiotics (like Bactrim) in your allergy list if you have lupus

Lupus patients are more likely to have allergies to antibiotics (plus, lupus and Bactrim are a bad combination)

While lupus and Bactrim are a bad combination, many systemic lupus erythematosus (SLE) patients also report numerous drug allergies. However, studies do not show an increased amount of allergies than non-lupus patients (other than antibiotics).

Lupus and antibiotics treatment:

SLE patients have higher rates of allergies and intolerances to penicillins, cephalosporins, sulfonamides, and the antibiotic erythromycin. The most important antibiotic intolerance is that of sulfonamide (often called “sulfa”) antibiotics. This most commonly refers to the antibiotic trimethoprim-sulfamethoxazole (Bactrim and Septra).

Sulfur versus sulfonamides versus other sulfa drugs and lupus

The element called sulfur exists in all of us, so none of us are allergic to sulfur. Many different molecules contain sulfur to include sulfates, sulfites, and sulfonamides. Lupus patients have an increased risk of antibiotic sulfonamides (specifically Bactrim, trimethoprim-sulfamethoxazole) flaring their lupus. Sulfonamide antibiotics are very different than sulfates, sulfites, and others. These are safe for lupus patients to take. There are some non-antibiotic sulfonamides (furosemide, hydrochlorothiazide, acetazolamide, sulfonylureas used for diabetes, and celecoxib). However, these do not appear to increase lupus flares and are safe for lupus patients to take (unless they just happen to have an allergy to that particular drug).

Sulfa antibiotics can cause significant lupus flares (list is as an allergy!)

Around one-third of lupus (SLE) patients have reactions to Bactrim, and it can cause lupus flares as well. These reactions are more common in Caucasians, those with low lymphocyte counts (lymphopenia), and anti-SSA positive patients. Still, they can occur in any lupus patient. They especially can cause flares of fever, sun-sensitive rashes, and low blood cell counts. Sometimes these flares can be severe. There are so many other antibiotics now available that sulfonamide antibiotics can usually be avoided in SLE patients.

I, and most lupus experts, recommend that all lupus patients always carry an up-to-date medication list (similar to the first image, above) and that it also includes an allergy list that includes “sulfa antibiotics.” This can protect you if you ever get sick and end up in the emergency room where it can be hard to remember to tell your entire medical history. While lupus patients are more likely to be intolerant of the antibiotics penicillin, cephalosporins, and erythromycin, these do not typically cause lupus flares, and the vast majority of SLE patients tolerate them well. Therefore, they do not need to be avoided in lupus patients who are not allergic to them.

Patient Question: “Can you take amoxicillin if you have lupus?”

“Yes!” The good news is that we have dozens of other safe antibiotics that lupus patients can take.  Lupus and antibiotics treatment should not be complicated. As long as you list “sulfa antibiotics” on your drug intolerance list and show it to doctors, they can come up with safe alternatives. Although lupus and Bactrim are a bad idea, lupus patients can take many other medications safely.

The Lupus Secrets

Learn and abide by the Lupus Secrets to live a healthier, longer life with SLE

This is my first blog post (as I stated I’d do in my 1st post) with one of my Lupus Secrets. It is such an important one! I will discuss the other “Secrets” in my blog in the future. 


Background of “The Lupus Secrets“:

A long time ago, I realized that most patients and most physicians were not familiar with all the important things that lupus patients can do themselves that improve their health and lives. So, I made a list and called them “The Lupus Secrets” that addresses these important things. I called them “The Lupus Secrets” not because I wanted them to be a secret, but because they appeared to be a secret since most people (and doctors) did not know about all of them.

I regularly update this list as our knowledge of lupus improves. The Lupus Secrets list is given to all my patients, and encourage them to follow it. Most of my SLE patients are in remission or low disease activity, and I care for many people with SLE. My patients’ utilization of “The Lupus Secrets” is an important tool in achieving this goal. Please download a copy. Each recommendation has medical literature to back it up (check out the references below for this “Secret”), though each varies in the strength of evidence. 

For more in-depth information on the Lupus Secrets:

Read chapter 44 of The Lupus Encyclopedia, edition 2

Look up your symptoms, conditions, and medications in the Index of The Lupus Encyclopedia

If you enjoy the information from The Lupus Encyclopedia, please click the “SUPPORT” button at the top of the page to learn how you can help. 

What are your comments and opinions?

If you have lupus, what has your experience been? What do you recommend for other patients?

Do you have any questions to ask Dr. Thomas?

Please click on “Leave a Comment” above to comment.

Please support “The Lupus Encyclopedia” blog post page

Click on “SUPPORT” at the top of the page to learn how you can support “The Lupus Encyclopedia


Don Thomas, MD
​Author of The Lupus Encyclopedia

Picture showing a bunch of people holding a sign in the shape of a cloud that says comment on lupus medication list and lupus sulfa allergy

What is your experience with sulfa antibiotics? Have you had any difficulties with your lupus and antibiotics treatment?

​Please click “Comments” 


  1. There are no references on your blog post. That’s seems very strange as a doctor. Please post references.

    • Cedens: Look at the very bottom of the post below my name. I included references there. They probably were just a little hidden below the post, and I did not notate in the text exactly which parts are referenced. I can’t figure out how to do superscripts on this website blog post. Dr. Michelle Petri at the Johns Hopkins Lupus Center especially helped to educate rheumatologists about the importance of sulfa intolerances in lupus patients and the importance of lupus medication lists way back in the early 1990s when I was still a rheumatology fellow. Unfortunately, there are not randomized, controlled trials, however, there never will be. All lupus docs have seen way too many bad reactions to sulfa to even try such a study.
      However, I completely agree with you, references are very important.
      Thanks for reading my post and I’ll make sure to put up helpful, practical posts regularly.
      Please share it with others who have lupus and if you have any special post requests, just let me know.

    • Also, in the future, I’ll make “references” in bold and black font to make it easier to see… thanks for asking about them

  2. I had back surgery in December and approx 8 days after getting my staples out I became extremely I’ll. Fever, chills, my incision had broken open and it was draining. I could barely get out of bed to go to the doctor’s office. Turned out I had a MRSA infection and I was prescribed Bactrim. I tolerated it well for the first ten days and then again for the next 10 days. The MRSA infection was being very stubborn and didn’t seem to be responding to the antibiotics. I only took two of the next seven day prescription when I broke out in the very worst rash I’ve ever had. It was literally from my head to my feet, it burned it itched and every bone in my body hurt!
    So a trip to the ER for prednisone, benadryl and a lotion for the itching. Life with Lupus!

    • Thank you for sharing your story, Cindy. I hope your story will help others with SLE learn to carry around an allergy list that includes Bactrim (sulfa antibiotics) so this does not happen to them. Thanks for reading my post.

  3. I love your blog posts, but the picture you used at the top listing Vitamin D2 as part of a medication list concerned me. Vitamin D3 is what is recommended for supplementation, due to its bioavailability. As many Lupus patients have low Vitamin D levels, it is important for them to know to supplement with D3, not D2.

    • Rebecca: I love your question. Oh… vitamin D… one of the most controversial subjects on the internet. I agree, it is such an important medication for most lupus medication lists. Actually either one can be used. It is OK if you are in the vit D3 camp, there are just as many in the vit D2 camp. They both actually achieve the same objectives in SLE patients, improving the immune system. Vitamin D3 has much better bioavailability. This is why we get away with lower doses of it compared to vitamin D2, but it doesn’t mean it is any better. Dr. Michelle Petri, in charge of the Lupus Center at Johns Hopkins primarily uses Vitamin D2 in her patients based upon studies such as: https:/ . I know Dr. Petri and know she uses the D2 form. Here is paper of hers about SLE management: https:/ … in the vitamin D section, she does not specify vit D3 or D2 since there are studies supporting both. Bottom line is that I do use both in my patients and get good results from both. It is also clear that we need better studies. We need large, excellent randomized controlled trials to number one prove causality of low vitamin D and abnormal immune system function, correcting vitamin D improves SLE function, and look in detail about the effects of vitamin D2 vs vitamin D3 when appropriate doses are used to get the 25-OH vit D to a target of 40 ng/mL.
      Thanks so much for reading my posts and commenting. This also reminds me a definite truism in medicine… 50% of what we “know” and teach today will be proven wrong in the future… the question is.. which 50%? (one of Dr. Philip Seu’s favorite lines at Johns Hopkins) … Dr T

  4. First time I was prescribed I had no reaction. The second time could have been different because of the UV exposure at the farmer’s market. Started out generally unwell and weak feeling. Then within 30 minutes it escalated to flu like feeling and by the time my parents met me at home to grab my son I was in severe pain all over. I was vomitting in all over body pain. I didn’t have the tongue swelling throat closing allergic reaction most would expect. My body was in chaos. My skin felt like it was on fire yet I had no temperature. My back felt like it was being ripped open. I was doubled over in pain yet needed to lay back gasping for air heaving my chest with rasping gasping breaths. The ER was confused because this isn’t a typical allergic reaction. Benadryl wasn’t touching it. I remember staying overnight with intravenoua steroid doses so large I didn’t recognize myself the next day.

    • Sorry to hear that Tiffany. Yours is not an unusual story at all. Thanks for sharing. Hopefully, others with lupus will read it and learn to add “sulfa allergy” to their list of allergies and carry it with their lupus medication list at all times. A common scenario is a lupus patients showing up at the ER with a UTI, then given Bactrim. If the person had an allergy list with them and gave it to the ER staff, it’d save them from this problem. Thanks for reading my post. I’ll continue to share practical, helpful advice

  5. As a pharmacist with lupus, I agree that when possible, one should avoid sulfa antibiotics in lupus patients to prevent flares and air on the side of caution. However, I will counter argue listing it as an allergy. Here’s why:
    1) When you list “sulfa antibiotics” as an allergy, it is considered an allergy for ALL sulfa drugs in your medical record. Simply because anyone with a sulfa allergy will have the potential to cross-react with any sulfonamide drugs. Pharmacists/providers will therefore air on the side of caution and avoid ANY sulfa drugs, not just antibiotics, especially with in someone with an unknown allergic reaction (which is the case for lupus patients). Now sulfa drugs is composed of MANY classes of medications including oral diabetic agents, diuretics for blood pressure, and celecoxib (Celebrex) – an NSAID. This could potentially delay treatment when picking up your medications at the pharmacy (pharmacists must verify with providers on drug allergy if prescribed sulfa drugs) or prevent you from receiving appropriate treatment. For example, a lupus patient with diabetes may have to resort to other, more expensive oral diabetic agents because of the listed sulfa allergy.
    2) There are only a handful of sulfa antibiotics available, the most common Bactrim (sulfamethoxazole/trimethoprim). I would recommend having a conversation with your doctor on the risks vs. benefits in taking sulfa antibiotics, rather than listing sulfa antibiotics as an allergy unless you truly are allergic. In the case of an emergency or hospitalization, you will be monitored and in the event of a flare will be managed appropriately.
    You as a lupus patient have the choice whether or not to list it as an allergy. My recommendation is to stay informed and talk with your doctor, if given sulfa antibiotics.

    • Van Vu:
      Of course you have a good point about the sulfonamide antibiotics vs other sulfonamides (other sulfonamides are safe for lupus patients). And, of course, an “intolerance” is a better term than “allergy.” I always try to figure out ways to make things as simple for non-medical people to remember as possible. This particular concept can really get quite complicated when you dive right into it (like the Dunning-Kruger effect).
      In my close to 30 years of having patients do this, I haven’t run into any docs not RXing non-abx sulfonamides (such as hypoglycemics) when patients list a sulfa antibiotic allergy (I don’t think most would have thought about it). However, now with more and more computer-assisted drug interactions programs being used, this could potentially happen. Today, I stress that it is only the sulfa-antibiotics (much easier for patients to remember than sulfonamide-antibiotics), and not other types of sulfa drugs. We have so many antibiotics today, that it is rare not to be able to find a substitute.
      I absolutely agree with your stressing the importance of having a conversation with your doctor. However, if you were to poll most doctors on giving Bactrim (sulfamethoxazole/trimethoprim) to an SLE patient, the vast majority would do so (not knowing the potential poor outcome). Even if a physician were to try to look up avoiding Bactrim in lupus patients in, this topic is only briefly mentioned (though it is) in the section on Pneumocystis pneumonia prevention of cyclophosphamide usage. (It really is hard to find if you search for it).
      I’ve seen way too many SLE patients have severe flares of their SLE after being RXd Bactrim in the ER for their UTI, that it is a very important thing for them to remember to do. I always struggle on how to make things as accurate for patients to remember, but also how to simplify it so it is easy to remember.
      I appreciate your reading my blog and commenting and hope to hear more from you in the future!

      • Like all lupus we appreciate the work that you do! I only learned about this most recently. You are absolutely right, very limited resources out there. I have been given Bactrim for PJP prophylaxis when on high-dose of prednisone. Luckily nothing happened.
        Again, thank you for your reply and the amazing work that you do for the lupus community.

  6. Dr Thomas, What about lupus and fluoroquinolones? There is a black box warning for that antibiotic, yet I was given it for a UTI despite being on long term steroids and having autoimmune disease. Both Achilles tore and my right ruptured which required surgery & lengthy recovery. I warn my friends about this class of drugs, while they may not have my reaction, usually not necessary for UTI.

    • smilachicago: Wow, so sorry to hear that! My go to antibiotic for UTIs is macrodantin. If I need to use Cipro or Levaquin, I ask my patients to rest as much as possible fo a couple of weeks. You are correct that we try to use other antibiotics instead (at least those of us who are aware of the black box warning). I sure hope you are doing better… Donald Thomas, MD

  7. Dr Thomas,

    Not completely on topic, but relevant to the antibiotic topic. What is your opinion regarding utilizing doxycycline as a potential anti-inflammatory medication for SLE? I had run across an interesting article written by Joewono Soeroso (A Rheumatologist from Indonesia). It provided a short argument for the use of doxycycline for treatment of SLE (along with supplemental additions to current treatments). I found it interesting, as there are quite a few people who treat rheumatoid conditions (RA, SSc, etc) with tetracycline-based antibiotics, but rarely do I see someone with Lupus doing so.

    I was just curious what your thoughts were.


    • Gabriel: I have actually used doxycycline and minocycline in my patients in the distant past, hoping it would help their lupus. I primarily tried it in patients who had concomitant osteoarthritis or rheumatoid arthritis as doxycycline does have anti-inflammatory properties and may benefit some RA and OA patients. Unfortunately, it did not help even after giving it a year (the recommended time for RA). I am not surprised since although it is antiinflammatory in some areas (such as metalloproteinases), there is no evidence for it helping lupus-associated immune system problems, such as lowering interferon gene signature levels or reducing B-cell activity. There are no research studies using it in lupus patients (at least I could not find any), so I cannot support its use after my experience and due to the lack of research.

      Interesting question, though.

      Donald Thomas, MD

  8. Hello,

    Thank you so much for posting about this. I had no idea that sulfa medications could cause lupus flares. I have lupus, sjogrens, and celiac disease. I recently been having eye troubles and got a really bad stye in my eye. I was prescribed bactrim for it. I was feeling fine until the last day of my antibiotic treatment, I woke up with hives on my trunk, thighs and chest (not itchy or painful) then I felt extremely feverish and had chills. Ive never felt so badly before. My joints hurt so bad I could barely move! The ER said it was just an allergic reaction but it did not feel like one at all. So I googled about lupus flares and medication and finally found the interesting link to certain antibiotics and lupus flares.

    • Laura: sorry to hear about your experience, but thanks for posting your experience. The more we can teach lupus patients to preemptively add sulfa abxs to their drug avoidance list, the better.

      All the best,

      Donald Thomas, MD

  9. Before I went to bed last night I had a random thought-get a life alert tag for sulfa meds. It gives me hives and severe vomiting. MSM is the same-I took some thinking it would help my joints a long time ago but did not read the label to see that S stands for sulfa!!!

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