Keflex and Heart rate irregular - a phase IV clinical study of FDA data

Summary:

Heart rate irregular is reported as a side effect among people who take Keflex (cephalexin), especially for people who are female, 60+ old, have been taking the drug for < 1 month also take Digoxin, and have Pain.

The phase IV clinical study analyzes which people have Heart rate irregular 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 Heart rate irregular?

Heart rate irregular is found to be associated with 1,513 drugs and 1,773 conditions by eHealthMe. Check the latest studies of Heart rate irregular.

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, 30, 2026

14,902 people reported to have side effects when taking Keflex.
Among them, 81 people (0.54%) have Heart rate irregular.

Could Keflex cause Heart rate irregular?

Among these 81 people:

How long have people been on Keflex when they have Heart rate irregular? *

What is the gender of people who have Heart rate irregular when taking Keflex? *

female: 66.67 %
male: 33.33 %

What is the age of people who have Heart rate irregular when taking Keflex? *

What are other drugs people take besides Keflex? *

What are other side effects people have besides Heart rate irregular? *

Dizziness: 40 people, 49.38%
Nausea (feeling of having an urge to vomit): 34 people, 41.98%
Dyspnea (difficult or laboured breathing): 34 people, 41.98%
Pain: 31 people, 38.27%
Atrial Fibrillation/flutter (atrial fibrillation and flutter are abnormal heart rhythms in which the atria, or upper chambers of the heart, are out of sync with the ventricles): 29 people, 35.80%
Headache (pain in head): 27 people, 33.33%
Hypotension (abnormally low blood pressure): 26 people, 32.10%
Heart Palpitations (feelings or sensations that your heart is pounding or racing): 26 people, 32.10%
Cough: 26 people, 32.10%
Fatigue (feeling of tiredness): 25 people, 30.86%

What are the existing conditions these people have? *

Pain: 20 people, 24.69%
Muscle Spasms (muscle contraction): 12 people, 14.81%
Bone Disorder: 11 people, 13.58%
High Blood Pressure: 11 people, 13.58%
Takayasu's Arteritis (an inflammation of the aorta -- the artery that carries blood from the heart to the rest of the body): 10 people, 12.35%
Insomnia (sleeplessness): 10 people, 12.35%
Dizziness: 10 people, 12.35%
Blood Disorder: 9 people, 11.11%
Bowel Movement Irregularity: 9 people, 11.11%
Dyspnea (difficult or laboured breathing): 9 people, 11.11%

* Approximation only. Some reports may have incomplete information.

Do you take Keflex and have Heart rate irregular?

- Check whether Heart rate irregular 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:

Keflex (15,844 reports)

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 Heart rate irregular:

Heart rate irregular (1,513 drugs)

Browse all the conditions that are associated with Heart rate irregular:

Heart rate irregular (1,773 conditions)

Related publications that referenced our studies

Agrawal A, Rao M, Jasdanwala S, Mathur A, Eng M, "Cephalexin Induced Cholestatic Jaundice", Case reports in gastrointestinal medicine, 2014 Aug .
Agrawal A, Rao M, Jasdanwala S, Mathur A, Eng M, "Cephalexin Induced Cholestatic Jaundice", Case reports in gastrointestinal medicine, 2014 Aug .

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.