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Sulfamethoxazole / trimethoprim and Rash: What Users Say

Brand names: Bactrim, Bactrim DS, SMZ-TMP DS, Septra, Co-trimoxazole, Septra DS, Bactrim Pediatric, Bactrim IV Sulfatrim Pediatric Bethaprim Bethaprim Pediatric …show all brand names

Rash: mentioned by 153 users (8.9%)

Based on user experiences from 1,720 Sulfamethoxazole / trimethoprim reviews, the following table shows the most commonly mentioned side effects.

All user comments are moderated by Drugs.com. Each review is verified for relevance and screened for inappropriate content. Side effects are user-reported and not clinically verified.

nausea 24.5%
headaches 19.1%
anxiety 11.8%
dizziness 9.4%
rash 8.9%
loss of appetite 7.6%
chills 7.3%
fever 7.2%
insomnia 7.2%
vomiting 6.2%

Reviews for Sulfamethoxazole / trimethoprim

Commonly mentioned side effects
  • Syn...
  • Taken for less than 1 month
  • January 10, 2020

For Urinary Tract Infection "First off, do NOT get scared by these reviews. Don't be scared to take a drug that may benefit you. Everybody's body processes medications differently. While someone may have a side effect, you may not. I had ZERO side effects on this medication, and I took it for 7 days. It did what it was supposed to. The people getting rashes and hives are allergic to it. That's not the drug's fault. It's not a death drug, so don't be scared of these reviews, and get better!"

9 / 10
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48 Report
  • Syn...
  • Taken for less than 1 month
  • January 10, 2020

For Urinary Tract Infection "First off, do NOT get scared by these reviews. Don't be scared to take a drug that may benefit you. Everybody's body processes medications differently. While someone may have a side effect, you may not. I had ZERO side effects on this medication, and I took it for 7 days. It did what it was supposed to. The people getting rashes and hives are allergic to it. That's not the drug's fault. It's not a death drug, so don't be scared of these reviews, and get better!"

9 / 10
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48 Report
  • Hil...
  • July 1, 2019

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "Have been struggling with UTIs despite my many and varied preventive measures. Had some backup Bactrim that I tried instead of the Augmentin I was prescribed. On both occasions, within a half hour, I was in massive extreme discomfort, my vagina was on fire. I assumed I had developed a curiously fast yeast infection and treated it that way but with little success. Having done some research, I now see it’s a less common but real side effect, similar to a swollen tongue or hives, the vagina is the area affected. Lesson learned, but terrible that this side effect isn’t mentioned more commonly, a nightmare."

1 / 10
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47 Report

Frequently asked questions

  • Ril...
  • Taken for less than 1 month
  • May 13, 2021

Sulfamethoxazole / trimethoprim for Bacterial Infection "I had a breast infection and was prescribed this terrible medicine. It needs to be off the market. I felt real bad the second day taking it. It caused a fever, rash, headache, sharp pains throughout my body, no appetite, shakiness, dizziness, and numbness. I felt so out of it, it scared me so bad I stopped taking it. The Bactrim medicine is too strong. I definitely wouldn’t recommend!"

2 / 10
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30 Report
  • Anonymous
  • October 9, 2009

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "I never had an allergic reaction until I took this medication. Now I learned the hard way I'm allergic to sulfa drugs. After one dose, I had a lot of serious side effects: high fever, intense stomach pain, insomnia, hallucinations, anxiety, non-stop chills/shaking, vomiting, and rash. Needless to say, I ended up in the hospital for 3 days. I think that you need to be careful when taking the drug and be aware of all the serious side effects."

1 / 10
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86 Report

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  • Kel...
  • Taken for less than 1 month
  • March 4, 2020

Sulfamethoxazole / trimethoprim for Bacterial Skin Infection "I was prescribed Bactrim for a 10-day course to treat a Staph infection in my skin. I had no issues other than fatigue for the first 6 days, but by day 7, I woke up feeling dizzy and so tired. I kept pushing on, taking the tablets because it was working to clear boils. By days 8-9, I had a rash over my body. I felt so lightheaded. Even lying down, my body ached as if I had the flu."

2 / 10
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32 Report
  • Lin...
  • Taken for less than 1 month
  • June 22, 2014

Sulfamethoxazole / trimethoprim for Kidney Infections "Took this medicine for a horrible, horrible, HORRIBLE kidney infection. Worked within 2 days and cleared up all of my symptoms, which was such a relief. I was told to finish off the bottle by my doctor, and the next day I developed a horrible case of the hives. I stopped taking the medicine immediately, but the hives stuck around for another 3 days. What a miserable week! So, Bactrim worked wonders for my kidney infection, but little did I know I was severely allergic to it. Take with caution."

5 / 10
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50 Report
  • Ano...
  • Taken for less than 1 month
  • September 26, 2018

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "I was prescribed this for a UTI. Worst experience ever! Got up to day 4 of taking it and started to feel weak, confused, had really bad back and neck pain, pain when I walked. I also had watery, itchy, burning eyes, a massive headache, sleepy and fatigue, and like a tight chest. At night, I couldn't sleep, had the chills and a cold sweat. I have lost my appetite and have lost 6 pounds in just 4 days! I have stopped taking them but now I am developing a rash on my body that really itches. Please, people beware of this. My advice is to ask for something else, or at the first sign of a symptom, stop taking."

1 / 10
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30 Report
  • Vin...
  • July 31, 2016

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "I've just finished my treatment for a urinary tract infection. I no longer have any symptoms from the infection. The first 8 days of a 15-day treatment were fine with no side effects. Beginning the 9th day, I began experiencing a mild rash and itching, which seemed to begin on my chest and neck and migrated to my back. A bit of a nuisance but tolerable. Around the 11th day, I began to experience mild joint and muscle aches and a tender scalp around the base of the skull. Acetaminophen and ibuprofen have helped to overcome this, but by the 14th and 15th day, I felt like I had the flu, with no nausea but a loss of appetite. I took the last pill this morning, and by 1 PM, had to lay down with chills, aches and pains, headache, and a slight fever."

6 / 10
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26 Report
  • Joe...
  • Taken for less than 1 month
  • December 28, 2016

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "Started taking Cipro for a bladder infection but had some bad side effects in the tendon in my right hand. Went back to the Dr. and he gave me Bactrim (Septra). I took it for 3 days in total before I had to stop. The symptoms literally made me feel like I was dying. I had a really foggy head, headaches, dizziness, I almost passed out one day. I got zero sleep the whole time I was on it. My joints hurt in the night, my skin got really itchy and developed a rash, I also developed extreme anxiety and I felt like I was having a heart attack with the palpitations. I was close to panic attack, that's when I said enough is enough. I've never had a reaction like that and I have trouble remembering those days. It was a blur of pain and confusion."

1 / 10
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31 Report
  • Anonymous
  • September 23, 2011

Sulfamethoxazole / trimethoprim for Bacterial Infection "I have only had this medicine twice. The first time was without reaction. The second time, however, I did experience trembling, weakness, especially in my legs, anxiety, and an itchy rash on my forearms. Not pleasant at all!"

5 / 10
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36 Report
  • ric...
  • November 8, 2017

Sulfamethoxazole / trimethoprim for Prostatitis "Prescribed Bactrim for prostatitis. Was showing good improvement after 5 days. Day 9, big full-body hives developed and had to stop. Dr. thought I was allergic to the sulfa component of Bactrim, so he prescribed Trimethoprim (the other component in Bactrim) by itself a week later. After 1 pill, the hives started again... Was switched to Cipro with slight improvement and then to Doxycycline, which is significantly helping after 4 weeks. Going to continue it as long as I'm improving. 70% better now."

8 / 10
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23 Report
  • Anonymous
  • Taken for less than 1 month
  • February 28, 2017

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "Worst medicine ever! I got this to get rid of my UTI, and while taking it, I had the worst side effects: itching, rash, headaches. And I am off the medication, finally, it's been a week now, and I am still getting headaches. I don't know what to do. I wish I never took it."

1 / 10
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23 Report
  • Anonymous
  • August 29, 2020

Sulfamethoxazole / trimethoprim for Bacterial Skin Infection "Took Bactrim for folliculitis. First 7 days I only had vomiting and nausea, but on Day 8 I started getting fevers, intense shaking, throbbing headache, sweating, vomiting, insomnia, depression. I never felt this sick ever. It took me a while to realize it was the antibiotic. Once I stopped taking it, I broke out in a rash. Ended up having a sulfa allergy. Please be cautious when taking this. There was one point where I just wanted to call 911, I was in so much agony... It did help clear up much of the infection."

2 / 10
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17 Report
  • SAa...
  • Taken for less than 1 month
  • January 25, 2020

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "This is the second time for me that this has been prescribed for a UTI. The side effects are beyond terrible. Every joint in my body ached, major fatigue, rash, eyes very bloodshot. The worst thing, though, was the dry, cracked lips and loss of mucus membranes in the vulvar, vaginal area. I have never heard of this kind of side effect, and neither did the urologist. This has happened both times I was on Bactrim. I stopped taking it and never will again."

1 / 10
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15 Report
  • mae...
  • October 30, 2019

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "I broke out with a rash just after day 10 of Bactrim, it was sudden and scared the heck out of me! I had a million red spots covered from head to toe (neck, stomach, back, and legs were the worst). I went into the clinic and they told me to stop taking it right away. So apparently, I am one of those 3% with a sulfa allergy. The funny thing is the nurse told me she also has an allergy to it. I then told a coworker about it, and she also had an allergy. With my follow-up appointment, I asked about the small percentage of patients affected-she told me it is rising and is much higher than it used to be (related it to the kind of rise we're seeing in gluten allergies). No reason! So if you get a rash, stop taking it! Day 1 rash recovery-slightly better, fewer red spots on ankles and feet. Day 2-much improved, fewer on shoulders/neck, and lower legs were cleared. Day 3-thighs are starting to clear as well as back/stomach. My temperature never went up during this process."

1 / 10
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16 Report
  • Anonymous
  • March 25, 2012

Sulfamethoxazole / trimethoprim for Bacterial Skin Infection "I am currently taking this medicine. I should be finishing it in two days. I have to take it twice for ten days. The whole time I've had migraines. And just recently, I got a rash because I forgot to take it once yesterday. I've never been allergic to anything, but I hope this rash goes away."

1 / 10
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36 Report
  • Gue...
  • April 22, 2012

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "I took Bactrim once for a urinary tract infection. I can't remember exactly how many days I was instructed to take the pill, but I know it was over a week. Everything was fine up until the 9th day, then my entire body broke out in hives."

5 / 10
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37 Report
  • Itc...
  • Taken for less than 1 month
  • April 22, 2020

Sulfamethoxazole / trimethoprim for Bacterial Skin Infection "My doctor prescribed 10 days of Bactrim DS after he drained an abscess in my upper arm. It definitely worked to heal the infection, but with my last few doses, I broke out in hives and am itching all over my body. Use this with caution."

7 / 10
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  • Anonymous
  • April 28, 2011

Sulfamethoxazole / trimethoprim for Bacterial Infection "Pain and swelling in the vicinity of my tailbone led to an emergency room visit where I had a pilonidal cyst drained. After the doctor incised and drained my cyst, he prescribed me Bactrim and Keflex. He explained that the Keflex was intended to treat the infection if it was MRSA while Bactrim would cover all other bases. A week into my 10-day course of antibiotics, I went to bed with a developing fever. In the morning, I awoke to discover that my entire body was covered in a red, splotchy rash. I immediately went to a medical professional who informed me that I was likely having a severe allergic reaction to Bactrim. I was informed that my fever and rash would persist for days to weeks and may progress to anaphylaxis."

2 / 10
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29 Report
  • Ell...
  • Taken for less than 1 month
  • May 3, 2015

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "Was prescribed Bactrim by a walk-in clinic. Should've known better. After 2 days, I experienced some awful side effects - chills, fevers, night sweats, insomnia, diarrhea, and migraines - for three days. I thought I was going to die. After I finished my prescription, I got this terrible head-to-toe rash that itches like crazy. My UTI is gone, but it was not worth the rash and three days of near death. Does anyone know what I can do for this rash?"

3 / 10
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29 Report
  • Ano...
  • Taken for less than 1 month
  • August 23, 2019

For Bacterial Skin Infection "I went to my doctor for a boil on my face and another on my lower lip. He prescribed Sulfamethoxazole TMP DS. I started it on a Monday, and by Tuesday morning, positive changes started to occur. The boil on my face stopped oozing, and the one on my lip stopped growing/being so painful. The good thing was my doctor prescribed the correct medication, and secondly, it started working right away. I took 2 tablets as soon as I got the script from the pharmacy to raise the level of this antibiotic in my bloodstream quickly. Then 1 tablet every 12 hrs of Sulfamethoxazole TMP DS for 10 days. Not many positive reviews of this med on this site, but after taking this for 4 days, my sores continue to heal and look better each day that passes. I have zero side effects. No rashes, bumps, insomnia, etc. No idea why others have experienced so many negative effects. I am very pleased with this antibiotic."

10 / 10
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  • hum...
  • Taken for less than 1 month
  • October 1, 2019

Sulfamethoxazole / trimethoprim for Prostatitis "Had TURP 17 years ago for prostate... not a great success. Recently had discomfort and some blood passing post-arousal. Not sure if prostatitis or UTI or both. Doc prescribed 10 days Bactrim 800 mg at 2 per day. All clear after 2 days, but some minor hives."

9 / 10
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  • Kat...
  • Taken for less than 1 month
  • October 29, 2019

Sulfamethoxazole / trimethoprim for Urinary Tract Infection "Was prescribed Bactrim for a UTI. Terrible side effects! I thought I had caught the flu, but when I went into the doctor, she said it was just a reaction to Bactrim. Fever (super uncomfortable, sweating and chills), body/joint aches and pains, extreme fatigue. Felt so sick and run down I didn’t want to get out of bed. The day after my last dose, I developed a bright red rash everywhere, which felt like it burned and itched. I had the worst week ever with this drug."

2 / 10
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12 Report
  • Sba...
  • Taken for less than 1 month
  • January 18, 2019

Sulfamethoxazole / trimethoprim for Kidney Infections "Horrible medication. Vomiting, skin rash, headache, joint pain. Can barely get off toilet, knees hurt so bad. Sore throat. I was okay until I took 1 pill. I'm worse from taking it. Should be classified as poison, not medication."

1 / 10
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Reviews may be edited to correct grammar/spelling or remove inappropriate content. Reviews appearing to come from parties with a vested interest are not published. This information is not intended to endorse any medication and should not replace the expertise and judgment of healthcare professionals.