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Delsym vs. Phenergan: side effect and effectiveness comparison (a real world drug study)

Summary:

We compare the side effects and drug effectiveness of Delsym and Phenergan. The phase IV clinical study is created by eHealthMe based on reports (from sources including the FDA) of 63,083 people who take Delsym and Phenergan, and is updated regularly.

What is Delsym?

Delsym has active ingredients of dextromethorphan polistirex. It is often used in cough. eHealthMe is studying from 5,033 Delsym users. Check the latest studies of Delsym.

What is Phenergan?

Phenergan has active ingredients of promethazine hydrochloride. It is often used in nausea. eHealthMe is studying from 25,312 Phenergan users. Check the latest studies of Phenergan.

On Jul, 02, 2026

63,083 people who take Delsym and Phenergan are studied.

Delsym vs Phenergan drug comparison reports.

Drugs being compared in this study:

  • Delsym (dextromethorphan polistirex)
  • Phenergan (promethazine hydrochloride)

Most common side effects of the drugs, overall:

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Most common side effects of the drugs, in long term (1+ years) use:

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Drug effectiveness:

Delsym:

  • not at all: 4.85 %
  • somewhat: 40.61 %
  • moderate: 29.09 %
  • high: 19.39 %
  • very high: 6.06 %

Phenergan:

  • not at all: 2.86 %
  • somewhat: 20.57 %
  • moderate: 34.88 %
  • high: 27.19 %
  • very high: 14.49 %

Want to compare Delsym with Phenergan?

- Personalize this study to your gender and age (0-99+)

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.

Related publications that referenced our studies

Related studies

Alternative drugs to, pros and cons of:

Browse all side effects of Delsym:

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 side effects of Phenergan:

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

How the study uses the data?

The study is based on dextromethorphan polistirex and promethazine hydrochloride (the active ingredients of Delsym and Phenergan, respectively). Other drugs that have the same active ingredients (e.g. generic drugs or brand names) are also considered. Dosage of drugs is not considered in the study.

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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