Cephalexin and blood sugar level?

Cephalexin and  Diabetes

Cephalexin and Diabetes

QUESTION: Cephalexin and blood sugar level? Does cephalexin increase blood sugar or lower it?

ANSWER: Hi there,

As you probably know, cephalexin is antibiotic, which means that it has the ability to kill bacteria.

In addition, I would like to inform you that the invasion of certain bacteria is considered as stress for the organism.

Because of this, the organism has to find a way in purpose to remove the bacteria and generally this “fight” requires a lot of energy and glucose respectively. This explains why when you are ill your blood glucose is high.

However, when you are using antibiotic, the invader is removed and the stress for the organism is wiped out.

Of course, there is no need for a lot of glucose (energy), which means that you glucose will come back to normal, or it will become lower, depending on the diabetic treatment during the infections.

  • Moreover, I need to inform you that Cephalexin is the generic name of the antibiotic; while you can find it under a lot of brand names.

    However, you have to remember something. When certain company produces cephalexin, or any other drugs, it is allowed to add certain ingredients to the formula.

    In other words, when you buy certain brand name of Cephalexin, you will get other substances as well. In addition, I have to tell you that some companies add glucose, or other sweet substances in purpose to improve the taste of the pill or of the beverage.

    As you can imagine the usage of antibiotic, which has glucose in it as sweetener, will damage your blood glucose control, by causing spikes in your blood glucose concentration.

    So, speak with your doctor about such things, when he is prescribing you antibiotics no matter their type.

    Hope it helped!



    Blood sugar up

    I have experienced this same phenomena since I started a course of Cephalexin. Readings went from 120's-130's to 150's-180's. Other online opinions on this seem mixed. Perhaps it's time for some clinical tests so that warnings can be posted.

    Rick G.

  • Comments for Cephalexin and blood sugar level?

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    Aug 26, 2021
    Blood sugar level
    by: Jim


    I just started taking the medication and I'm wondering prior to me taking the medication my blood sugar levels were normal now since I started taking this my blood sugar levels are like 71 79 82 whenever I tested throughout the day.

    So I'm wondering can this also be answer to be a medication that lowers blood sugar level?

    ANSWER: Hello,

    I understand your concern.

    Indeed, many medications used to treat diabetes work by lowering blood sugar levels.

    If you have recently started taking a medication for diabetes, it is possible that your blood sugar levels have decreased as a result of the medication.

    However, it is important to note that blood sugar levels can vary throughout the day and can be influenced by factors such as food, exercise, stress, and illness.

    It is also possible that your blood sugar levels would have naturally decreased even if you did not start taking the medication.

    If you have recently started taking a medication for diabetes and your blood sugar levels have decreased, it is possible that the medication is responsible for the decrease.

    I would suggest to keep monitoring your blood sugar levels, and continue the medications as prescribed by your doctor.

    If you will notice any unusual symptoms, should consult with your caring doctor in order to make appropriate changes in your therapy.

    Hope this helps.


    May 09, 2021
    Lows, Not Highs
    by: Cheryl

    I'm Type 2 Diabetic taking Cephalexin following ICD replacement surgery. My blood sugar has been dipping to 65. I watched it go from 139 mg/dL to 65 mg/dL in a period of just two hours. My lows are usually 72-74.

    I'm sure it's the Cephalexin — I'm not doing anything else differently.

    The doctors who prescribed this antibiotic know I'm diabetic so I'll just have to keep a close eye out.

    Feb 26, 2018
    blood sugar spike after taking antibiotic
    by: Tim

    QUESTION: Hello,

    I have been prescribed cephalexin 500MG for a very bad allergic reaction. The problem is my blood sugar went up to 267 it normally runs about 115. I will retest it in the AM.

    Should I continue?

    ANSWER: Hello,

    I understand your concern.

    1. First let me explain that cephalexin is an antibiotic. It is used to treat bacterial infections.

    Usually, we do prescribe it for a bacterial infection of the skin, lungs, or others.

    We do not prescribe for allergy reaction.

    2. You are worried because you found that your blood sugar levels raised up to 267 mg/dL. That's a bit high in fact.

    However, there are 2 main things to point out in here:
    - you had an allergy reaction. That will increase your blood sugar as it is considered a stress situation.
    - it's true that Cephalexin can raise blood sugar but not at this point as in your case. There is something else going on here.

    And you are right. Further tests are required to determine the right diagnosis:
    - complete blood count
    - fasting blood sugar test
    - oral glucose tolerance test
    - HbA1C test

    After getting the results, send to me to evaluate them adequately.

    Perhaps you had an impaired blood glucose before taking Cephalexin, and its use has triggered it.

    Hope this helps. Let me know if you have any other concern.

    Nov 07, 2017
    Cephalexin effect on fasting blood sugar?
    by: Anonymous

    HELLO: Hello,

    I tested my blood sugar yesterday morning,it was 118 normal for my fasting test.

    I got a prescription of cephalexin for chest/lung infection,this morning my blood sugar is 191 fasting,it has never been over 138 fasting?

    ANSWER: Hello,

    Thank you for trusting us your medical concern.

    I advise to keep monitoring your blood sugar levels, and record the results for reference.

    Meanwhile, continue taking cephalexin as prescribed by your doctor.

    I also advise to run HBA1C test to evaluate the mean of your blood sugar the last 3 months.

    Try to be careful with foods you consume; try to be physically active.

    Hope this answers your query. Let me know if you have any other concern.


    Sep 17, 2017
    Sugar level rising
    by: Anonymous

    QUESTION: My mother is diabetic and was recently given cephalexin to take 4 times a day. In morning level is normal. As the day goes on by time for her 3rd dose about diner time. Her sugar is at about 186 and at bedtime close to 200.. is that normal with this med?

    ANSWER: Hi,

    I understand your concern.

    Your mother's blood sugar levels are acceptable although she is taking cephalexin. I advise to continue taking this antibiotic as prescribed and to take other hypoglycemiant agents as recommended by her doctor.

    Be careful with food she is eating; diet is also very important.

    In general, her blood sugar levels are ok.

    Let me know if you have other queries.


    Aug 10, 2017
    Blood sugar went up after taking antibiotic Zithromax (Azithromycin)
    by: Tim

    QUESTION: My blood sugars have gone up after taking Zirthomax. Azithromycin.

    I called doc and waiting for his response. It has raised my blood sugar in the morning by about 30-40 points.

    ANSWER: Hi Tim,

    I understand your concern.

    Zithromax is the brand name for the antibiotic Azithromycin. I believe you are taking pills form and not suspension.

    Now, azithromycin can alter liver function sometimes. As liver is responsible for accumulation and production of glucose in the body; alteration in its function can cause oscillations in blood sugar too.

    To be more specific, I need to have your blood glucose levels checked:
    - at bedtime
    - early in the morning
    - 2 hours after eating

    Thank you.

    Nov 09, 2014
    blood sugar increased after taking cephalexin
    by: newman


    My blood sugar also went up 100 points after I started taking cephalexin.

    Answer: Hi,

    Thank you for sharing with your your concern.

    If you think that your blood sugar level went up 100 points after started taking cephalexin, I advise to report this to the doctor who prescribed cephalexin.

    You might need to change therapy or adjust the dosage of current hypoglycemiant medications.

    All the best!

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