Keflex and Haematemesis - a phase IV clinical study of FDA data

Summary:

Haematemesis 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 Ketek, and have Bronchitis.

The phase IV clinical study analyzes which people have Haematemesis 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 Haematemesis?

Haematemesis (vomiting of blood) is found to be associated with 1,465 drugs and 2,232 conditions by eHealthMe. Check the latest studies of Haematemesis.

On Jul, 13, 2026

14,902 people reported to have side effects when taking Keflex.
Among them, 45 people (0.3%) have Haematemesis.

Among these 45 people:

How long have people been on Keflex when they have Haematemesis? *

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

female: 75.56 %
male: 24.44 %

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

What are other drugs people take besides Keflex? *

What are other side effects people have besides Haematemesis? *

Nausea (feeling of having an urge to vomit): 23 people, 51.11%
Weakness: 23 people, 51.11%
Nausea And Vomiting: 21 people, 46.67%
Fever: 17 people, 37.78%
Acute Kidney Failure: 14 people, 31.11%
Oedema Peripheral (superficial swelling): 13 people, 28.89%
Ascites (accumulation of fluid in the abdominal cavity): 12 people, 26.67%
Pain: 12 people, 26.67%
Multi-Organ Failure (multisystem organ failure): 12 people, 26.67%
Pleural Effusion (water on the lungs): 12 people, 26.67%

What are the existing conditions these people have? *

Bronchitis (inflammation of the mucous membrane in the bronchial tubes): 10 people, 22.22%
Gastritis (inflammation of stomach): 6 people, 13.33%
Sinusitis (inflammation of sinus): 6 people, 13.33%
Pneumonia: 5 people, 11.11%
Chronic Fatigue Syndrome (disorder that causes extreme fatigue): 4 people, 8.89%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 4 people, 8.89%
Depression: 4 people, 8.89%
Pain: 4 people, 8.89%
Osteoporosis Post-Menopausal (weak bone with possibility to break after stopped menstrual cycles): 3 people, 6.67%
Multiple Sclerosis (a nervous system disease that affects your brain and spinal cord. it damages the myelin sheath): 2 people, 4.44%

* Approximation only. Some reports may have incomplete information.

Do you take Keflex and have Haematemesis?

- Check whether Haematemesis 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)

Haematemesis treatments and more:

Haematemesis (33,968 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 Haematemesis:

Haematemesis (1,465 drugs)

Browse all the conditions that are associated with Haematemesis:

Haematemesis (2,232 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.