Concerns for athletes and active people taking antibiotics

Whether or not you play competitive sports, I would bet that most of you at least engage in regular exercise or other athletic activity. Unfortunately you also get sick occasionally. I have previously offered suggestions for safely exercising and playing sports when you’re sick. In this post, I would specifically like to focus on antibiotics.

Athletes take oral antibiotics more than twice as often as non-athletes. Maybe the team doctors are trying to get them back to sports as soon as possible. Maybe active people fear an infection worsening and keeping them from training.

A new review article published in Sports Health offers some warnings and possible side effects from commonly used antibiotics. Since many of us take antibiotics, even when we are training or competing, it is worthwhile to summarize the authors’ findings here.

Tendon injuries

No antibiotic complication among athletes has received more attention then the risk of tendon rupture from fluoroquinolones. This category of drugs includes ciprofloxacin (Cipro) and levofloxacin (Levaquin). They are often used to treat urinary infections. While all Runnertendons could potentially be affected, the Achilles tendon might be most at risk. Patients who take these medications appear to have 3 to 6 times increased risk of Achilles tendon rupture.

Doctors might consider using different antibiotics in athletes. Athletic people should inquire about the risk of tendinitis and tendon rupture before taking these antibiotics.


Antibiotic-associated diarrhea can occur with many types of antibiotics. These medications can alter the normal bacteria in the G.I. system. In order to decrease the chance of diarrhea, healthcare professionals could keep duration of antibiotic treatment to as short a period as possible that would eliminate the infection. Using certain broad-spectrum antibiotics might increase this risk. Doctors could use more narrow-spectrum medications if possible.

Cardiac arrhythmias

Certain antibiotics present an increased risk of heart arrhythmias (abnormal heartbeats or electrical patterns). Prolonged QT interval is an example of one of the possible cardiac changes. Azithromycin, clarithromycin, fluoroquinolones and others carry these risks. It is important that a sports medicine doctor who performs pre-participation physical exams ask about antibiotic use if he detects one of these arrhythmias. Also patients with underlying heart or the medical conditions could have increased risk with these antibiotics.


An athlete who competes in outdoor sports or who exercises or trains outdoors could suffer a photosensitivity reaction. Tetracyclines, sulfa drugs and fluoroquinolones present this risk. She could develop a serious sunburn on body parts exposed to the sun. She could also have increased risk of skin cancer. An athlete who will compete in the sun should avoid these antibiotics or use sunscreen and wear fully protective clothing.

Decreased athletic performance

Many antibiotics could possibly cause fatigue or decreased performance. It is difficult to know if this is a side effect of the antibiotic or a result of the underlying illness.

If an athletic or active individual has an infection and requires antibiotic treatment, she should ask the doctor about possible complications with those drugs, especially as they pertain to exercise and sports. This post is in no way meant to offer specific medical advice, so please consult your doctor with specific questions.

While the risk of these complications appears to be small, do they concern you as an athlete or healthcare provider? Do you have any tips to share?

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Fayock K, Voltz M, Sandella B, Close J, Lunser M, Okun J. Antibiotic precautions in athletes. Sports Health: A Multidisciplinary Approach. Published online ahead of print September 26, 2013.

22 Responses to Concerns for athletes and active people taking antibiotics

  1. 10 months after a 3 week therapy of cipro 500 mg twice a day I am dealing with the most horrendous case of peripheral neuropathy in both legs. Shins and calves feel like they have been burned. In my 33 years of serious recreation I have been around the earth’s circumference 2 times. I am a 60 year old male who has been stopped dead in his tracks. I hope and pray that I will heal in time and that I am not a permanent causualty of FQ poisoning. Any feedback would be greatly appreciated.

  2. Good Day
    I run 10 kms a day and 30 mins of gym per day 5 days a week. I developed a tooth abcess and was put on clindahexal antibiotics. As the package insert talks about stomach upsets mainly, I am also on interflora 3 x daily so that’s OK. My concern is I sweat an get so hot , also get exhausted, dizzy an nauseas. Due to the exhaustion can I exercise or not as I don’t want to damage my heart.
    Kind Regards

  3. Hi,

    i would like to find out how long you have to wait before you can go back to cardio or any kind of gym after using antibiotics? i used Augmentin SR for a week – first day off- i haven’t been to the gym since i started it. Very bad flue.
    can i do cardio tonight ? or is it bad?

  4. Hi, Im on Cyfrox day 2 for 10 days.i have a 50kmrace in 7 days, i need more miles forfew days. doesthe meds weaken muscles and chance to rapture tendons?
    i told the doctor i have race in a week. he still give me Cyfrox and Metronidazole.

  5. my son is on Bactrim and he does intense cardio workouts 6 days a week and sweats so much. Can this effect the medication from working properly?

  6. Hi just reading your article about antibiotics and sports and have a question. I train in the gym just my usual squatting bench and deadlift, and lift really heavy. squat over 180kg deadlift over 230kg but was just reading up about rupturing tendons and ligaments while on antibiotics as they can weaken them apperently and just wanted to know if this true. I’m taking Rifadin capsules 300mg 1 twice a day and Dalacin c 150mg 2 twice a day for 6 wks for rash on back of my head. I Would love to hear your professional opinion on this to ease my mind. TYIA Alan

  7. I take 5mg of prednisone daily and recently used approximately five 500mg cipro pills for an UTI would it be safe to run a day or two later after discontinuing Cpro? I’m 5’8″ and 174 lbs. (Yes. I’m trying to lose weight)

  8. Augusto Sanchez:
    Today I’ve been given prescription to take 3 capsules daily “amoxcillin 500 mg”, so no matter how much I love to play tennis I decided
    to stop playing tennis until I’m done with the antibiotics.

  9. Dr. Geier,

    My teenage daughter is a distance runner. She was prescribed Amoxicillin prophylactic after a normal wisdom tooth procedure. She is concerned the antibiotic will slow her running. How long could might the affects last? Her next race is months away. Obviously an infection would not help.


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