Keflex and Iron deficiency - a phase IV clinical study of FDA data


Iron deficiency is found among people who take Keflex, especially for people who are female, 30-39 old, have been taking the drug for < 1 month.

The phase IV clinical study analyzes which people take Keflex and have Iron deficiency. It is created by eHealthMe based on reports of 13,830 people who have side effects when taking Keflex from the FDA, and is updated regularly. You can use the study as a second opinion to make health care decisions.

Phase IV trials are used to detect adverse drug outcomes and monitor drug effectiveness in the real world. With medical big data and AI algorithms, eHealthMe is running millions of phase IV trials and makes the results available to the public. Our original studies have been referenced on 600+ medical publications including The Lancet, Mayo Clinic Proceedings, and Nature.

On Sep, 27, 2022

13,830 people reported to have side effects when taking Keflex.
Among them, 29 people (0.21%) have Iron deficiency.

What is Keflex?

Keflex has active ingredients of cephalexin. It is often used in infection. eHealthMe is studying from 14,739 Keflex users for its effectiveness, alternative drugs and more.

What is Iron deficiency?

Iron deficiency is found to be associated with 1,135 drugs and 604 conditions by eHealthMe.

Number of Keflex and Iron deficiency reports submitted per year:

Could Keflex cause Iron deficiency?

Time on Keflex when people have Iron deficiency *:

  • < 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 %

Gender of people who have Iron deficiency when taking Keflex *:

  • female: 58.62 %
  • male: 41.38 %

Age of people who have Iron deficiency when taking Keflex *:

  • 0-1: 0.0 %
  • 2-9: 0.0 %
  • 10-19: 0.0 %
  • 20-29: 0.0 %
  • 30-39: 68.97 %
  • 40-49: 6.9 %
  • 50-59: 6.9 %
  • 60+: 17.24 %

Common drugs people take besides Keflex *:

  1. Atarax: 21 people, 72.41%
  2. Prilosec: 21 people, 72.41%
  3. Tylenol: 16 people, 55.17%
  4. Flonase: 15 people, 51.72%
  5. Albuterol: 14 people, 48.28%
  6. Prednisone: 14 people, 48.28%
  7. Alprazolam: 13 people, 44.83%
  8. Rocephin: 13 people, 44.83%
  9. Medrol: 12 people, 41.38%
  10. Lantus: 12 people, 41.38%

Common side effects people have besides Iron deficiency *:

  1. High Blood Pressure: 25 people, 86.21%
  2. Weakness: 23 people, 79.31%
  3. Anaemia (lack of blood): 21 people, 72.41%
  4. Constipation: 20 people, 68.97%
  5. Insomnia (sleeplessness): 19 people, 65.52%
  6. Fatigue (feeling of tiredness): 17 people, 58.62%
  7. Swallowing Difficulty: 16 people, 55.17%
  8. Sinusitis (inflammation of sinus): 14 people, 48.28%
  9. Pain In Extremity: 13 people, 44.83%
  10. Rashes (redness): 13 people, 44.83%

Common conditions people have *:

  1. High Blood Pressure: 12 people, 41.38%
  2. Eczema (patches of skin become rough and inflamed, with itching and bleeding blisters): 11 people, 37.93%
  3. Wheezing (a high-pitched whistling sound made while you breath): 10 people, 34.48%
  4. Pain: 10 people, 34.48%
  5. Infective Pulmonary Exacerbation Of Cystic Fibrosis (severe infective lung disease with production of abnormally thick mucus): 9 people, 31.03%
  6. Asthma: 9 people, 31.03%
  7. Attention Deficit Hyperactivity Disorder (a chronic condition including attention difficulty, hyperactivity, and impulsiveness): 9 people, 31.03%
  8. Blood Glucose Decreased: 9 people, 31.03%
  9. Bronchitis (inflammation of the mucous membrane in the bronchial tubes): 9 people, 31.03%
  10. Cough: 9 people, 31.03%

* Approximation only. Some reports may have incomplete information.

Do you take Keflex and have Iron deficiency?

Check whether Iron deficiency is associated with a drug or a condition

How to use the study?

You can discuss the study with your doctor, to ensure that all drug risks and benefits are fully discussed and understood.

Related publications that referenced our studies

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How severe was Iron deficiency and when was it recovered:

Expand to all the drugs that have ingredients of cephalexin:

Alternative drugs to, pros and cons of Keflex:

Common Keflex side effects:

Browse all side effects of Keflex:

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Iron deficiency treatments and more:

COVID vaccines that are related to Iron deficiency:

Common drugs associated with Iron deficiency:

All the drugs that are associated with Iron deficiency:

Common conditions associated with Iron deficiency:

All the conditions that are associated with Iron deficiency:

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.

Who is eHealthMe?

With medical big data and proven AI 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 600+ 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: Please DO NOT STOP MEDICATIONS without first consulting a physician since doing so could be hazardous to your health.

DISCLAIMER: All material available on 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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