Promethazine and Muscle rigidity - a phase IV clinical study of FDA data

Summary:

Muscle rigidity is reported as a side effect among people who take Promethazine (promethazine hydrochloride), especially for people who are female, 40-49 old, have been taking the drug for 1 - 6 months also take Fluoxetine, and have Shock.

The phase IV clinical study analyzes which people have Muscle rigidity when taking Promethazine. It is created by eHealthMe based on reports of 31,259 people who have side effects when taking Promethazine from the FDA, and is updated regularly.

What is Promethazine?

Promethazine has active ingredients of promethazine hydrochloride. It is often used in nausea. eHealthMe is studying from 32,300 Promethazine users. Check the latest studies of Promethazine.

What is Muscle rigidity?

Muscle rigidity (muscle stiffness) is found to be associated with 780 drugs and 1,036 conditions by eHealthMe. Check the latest studies of Muscle rigidity.

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, 31, 2026

31,259 people reported to have side effects when taking Promethazine.
Among them, 27 people (0.09%) have Muscle rigidity.

Could Promethazine cause Muscle rigidity?

Among these 27 people:

How long have people been on Promethazine when they have Muscle rigidity? *

What is the gender of people who have Muscle rigidity when taking Promethazine? *

female: 52.94 %
male: 47.06 %

What is the age of people who have Muscle rigidity when taking Promethazine? *

What are other drugs people take besides Promethazine? *

What are other side effects people have besides Muscle rigidity? *

Fever: 14 people, 51.85%
Serotonin Syndrome (occurs when two drugs that affect the body's level of serotonin are taken together at the same time): 13 people, 48.15%
Overdose: 10 people, 37.04%
Pupil Fixed: 9 people, 33.33%
Clonus (series of involuntary, rhythmic, muscular contractions and relaxations): 9 people, 33.33%
Hypoventilation (too shallow or too slow breathing, which does not meet the needs of the body): 8 people, 29.63%
Muscle Function Loss: 8 people, 29.63%
Agitation (state of anxiety or nervous excitement): 8 people, 29.63%
Autonomic Nervous System Imbalance (autonomic nervous system is of net equal emphasis): 6 people, 22.22%
Hyperreflexia (overactive or over responsive reflexes): 6 people, 22.22%

What are the existing conditions these people have? *

Schizophrenia (a mental disorder characterized by a breakdown of thought processes): 4 people, 14.81%
Shock (a life-threatening condition with symptoms like low blood pressure, weakness, shallow breathing, cold, clammy skin): 4 people, 14.81%
Essential Hypertension (primary hypertension): 3 people, 11.11%
Depression: 3 people, 11.11%
Sedation: 2 people, 7.41%
Parkinson's Disease: 2 people, 7.41%
Pain: 2 people, 7.41%
Vasoplegia Syndrome (low systemic vascular resistance): 1 person, 3.70%
Back Pain: 1 person, 3.70%
Bipolar Disorder (mood disorder): 1 person, 3.70%

* Approximation only. Some reports may have incomplete information.

Do you take Promethazine and have Muscle rigidity?

- Check whether Muscle rigidity 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 Promethazine:

Promethazine (32,300 reports)

Muscle rigidity treatments and more:

Muscle rigidity (16,888 reports)

Browse all side effects of Promethazine:

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 Muscle rigidity:

Muscle rigidity (780 drugs)

Browse all the conditions that are associated with Muscle rigidity:

Muscle rigidity (1,036 conditions)

Related publications that referenced our studies

Teimoory M, Arefi M, Behnoush B, Bastani B, "Promethazine and Treatment Refractory Agitation in Clonidine Toxicity", International Journal of Medical Toxicology and Forensic Medicine, 2013 Mar .
Teimoory M, Arefi M, Behnoush B, Bastani B, "Promethazine and Treatment Refractory Agitation in Clonidine Toxicity", International Journal of Medical Toxicology and Forensic Medicine, 2013 Mar .

How the study uses the data?

The study uses data from the FDA. It is based on promethazine hydrochloride (the active ingredients of Promethazine) and Promethazine (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.