Keflex and Infected cyst - a phase IV clinical study of FDA data

Summary:

Infected cyst is reported as a side effect among people who take Keflex (cephalexin), especially for people who are female, 50-59 old, have been taking the drug for < 1 month also take Sodium Chloride, and have Immunodeficiency common variable.

The phase IV clinical study analyzes which people have Infected cyst when taking Keflex. It is created by eHealthMe based on reports of 14,902 people who have side effects when taking Keflex from the FDA, and is updated regularly.

What is Keflex?

Keflex has active ingredients of cephalexin. It is often used in infection. eHealthMe is studying from 15,844 Keflex users. Check the latest studies of Keflex.

What is Infected cyst?

Infected cyst is found to be associated with 200 drugs and 260 conditions by eHealthMe. Check the latest studies of Infected cyst.

eHealthMe: drug outcomes in the real world

eHealthMe runs one of the largest post-marketing drug safety studies in the world. We study millions of patients and 5,000 more each day. Our data-driven phase IV clinical trials have been referenced on 800+ peer-reviewed medical publications including The Lancet, Mayo Clinic Proceedings, and Nature. Tools to study our phase IV findings are available to the public, anonymous and free >>>.



On Aug, 20, 2026

14,902 people reported to have side effects when taking Keflex.
Among them, 12 people (0.08%) have Infected cyst.

Could Keflex cause Infected cyst?

Among these 12 people:

How long have people been on Keflex when they have Infected cyst? *

  • < 1 month: 100 %
  • 1 - 6 months: 0.0 %
  • 6 - 12 months: 0.0 %
  • 1 - 2 years: 0.0 %
  • 2 - 5 years: 0.0 %
  • 5 - 10 years: 0.0 %
  • 10+ years: 0.0 %

What is the gender of people who have Infected cyst when taking Keflex? *

  • female: 75 %
  • male: 25 %

What is the age of people who have Infected cyst when taking Keflex? *

  • 0-1: 0.0 %
  • 2-9: 0.0 %
  • 10-19: 0.0 %
  • 20-29: 22.22 %
  • 30-39: 22.22 %
  • 40-49: 0.0 %
  • 50-59: 55.56 %
  • 60+: 0.0 %

What are other drugs people take besides Keflex? *

  1. Epinephrine: 4 people, 33.33%
  2. Azithromycin: 4 people, 33.33%
  3. Sodium Chloride: 4 people, 33.33%
  4. Zolpidem Tartrate: 3 people, 25.00%
  5. Dextroamphetamine Sulfate: 3 people, 25.00%
  6. Potassium Chloride: 3 people, 25.00%
  7. Potassium: 3 people, 25.00%
  8. Clonidine Hydrochloride: 3 people, 25.00%
  9. Norco: 3 people, 25.00%
  10. Nitrofurantoin: 3 people, 25.00%

What are other side effects people have besides Infected cyst? *

  1. Rashes (redness): 5 people, 41.67%
  2. Abdominal Pain Upper: 3 people, 25.00%
  3. Sinusitis (inflammation of sinus): 3 people, 25.00%
  4. Localised Infection (infection at the single location): 3 people, 25.00%
  5. Epstein-Barr Virus Infection: 3 people, 25.00%
  6. Lyme Disease (a bacterial infection that is spread to humans by infected ticks): 3 people, 25.00%
  7. Malaise (a feeling of general discomfort or uneasiness): 3 people, 25.00%
  8. Nausea (feeling of having an urge to vomit): 3 people, 25.00%
  9. Peripheral Swelling: 3 people, 25.00%
  10. Pharyngitis (inflammation of the pharynx, causing a sore throat): 3 people, 25.00%

What are the existing conditions these people have? *

  1. Weight Decreased: 3 people, 25.00%
  2. Sinusitis (inflammation of sinus): 3 people, 25.00%
  3. Rhinitis (a medical term for irritation and inflammation of the mucous membrane inside the nose): 3 people, 25.00%
  4. Otitis (ear infection): 3 people, 25.00%
  5. Immunodeficiency Common Variable: 3 people, 25.00%
  6. Cough: 2 people, 16.67%
  7. Ulcerative Colitis (inflammatory bowel disease (ibd). it causes swelling, ulcerations, and loss of function of the large intestine): 2 people, 16.67%
  8. Dyskinesia (abnormality or impairment of voluntary movement): 2 people, 16.67%
  9. Fungal Infection: 2 people, 16.67%
  10. Gastroenteritis Viral (inflammation of stomach and intestine caused by virus infection): 1 person, 8.33%

* Approximation only. Some reports may have incomplete information.

Do you take Keflex and have Infected cyst?

- Check whether Infected cyst is associated with a drug or a condition
- Predict drug outcomes for up to one year with AI
- Get an AI agent to monitor your drugs continuously



Related studies:

Effectiveness of, long term effects of, and alternative drugs to Keflex:

Infected cyst treatments and more:

How severe was Infected cyst and when was it recovered:

Expand to all the drugs that have ingredients of cephalexin:

Sub-studies by gender and age:

Female: 0-1 2-9 10-19 20-29 30-39 40-49 50-59 60+

Male: 0-1 2-9 10-19 20-29 30-39 40-49 50-59 60+

Browse all side effects of Keflex:

a b c d e f g h i j k l m n o p q r s t u v w x y z

Browse all the drugs that are associated with Infected cyst:

Browse all the conditions that are associated with Infected cyst:

Related publications that referenced our studies


How the study uses the data?

The study uses data from the FDA. It is based on cephalexin (the active ingredients of Keflex) and Keflex (the brand name). Other drugs that have the same active ingredients (e.g. generic drugs) are not considered. Dosage of drugs is not considered in the study.

How to use the study?

DO NOT STOP MEDICATIONS without first consulting your doctor. If there are any serious or long term adverse effects discovered in the study, discuss the study with your doctor to ensure that proper medication management will be in place if applicable.

Who is eHealthMe?

With medical big data and proven AI/ML algorithms, eHealthMe provides a platform for everyone to run phase IV clinical trials. We study millions of patients and 5,000 more each day. Results of our real-world drug study have been referenced on 800+ peer-reviewed medical publications, including The Lancet, Mayo Clinic Proceedings, and Nature. Our analysis results are available to researchers, health care professionals, patients (testimonials), and software developers (open API).

WARNING, DISCLAIMER, USE FOR PUBLICATION

WARNING: Please DO NOT STOP MEDICATIONS without first consulting a physician since doing so could be hazardous to your health.

DISCLAIMER: All material available on eHealthMe.com is for informational purposes only, and is not a substitute for medical advice, diagnosis, or treatment provided by a qualified healthcare provider. All information is observation-only. Our phase IV clinical studies alone cannot establish cause-effect relationship. Different individuals may respond to medication in different ways. Every effort has been made to ensure that all information is accurate, up-to-date, and complete, but no guarantee is made to that effect. The use of the eHealthMe site and its content is at your own risk.

If you use this eHealthMe study on publication, please acknowledge it with a citation: study title, URL, accessed date.



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