Contac 12 hour and Visual acuity reduced - a phase IV clinical study of FDA data

Summary:

Visual acuity reduced is reported as a side effect among people who take Contac 12 hour (chlorpheniramine maleate; phenylpropanolamine hydrochloride), especially for people who are male, 40-49 old, have been taking the drug for 1 - 2 years also take Dimetapp, and have Nasopharyngitis.

The phase IV clinical study analyzes which people have Visual acuity reduced when taking Contac 12 hour. It is created by eHealthMe based on reports of 1,131 people who have side effects when taking Contac 12 hour from the FDA, and is updated regularly.

What is Contac 12 hour?

Contac 12 hour has active ingredients of chlorpheniramine maleate; phenylpropanolamine hydrochloride. eHealthMe is studying from 1,137 Contac 12 hour users. Check the latest studies of Contac 12 hour.

What is Visual acuity reduced?

Visual acuity reduced (reduced clearness of vision) is found to be associated with 1,493 drugs and 1,887 conditions by eHealthMe. Check the latest studies of Visual acuity reduced.

On Jul, 13, 2026

1,131 people reported to have side effects when taking Contac 12 hour.
Among them, 22 people (1.95%) have Visual acuity reduced.

Could Contac 12 hour cause Visual acuity reduced?

Among these 22 people:

How long have people been on Contac 12 hour when they have Visual acuity reduced? *

What is the gender of people who have Visual acuity reduced when taking Contac 12 hour? *

female: 50 %
male: 50 %

What is the age of people who have Visual acuity reduced when taking Contac 12 hour? *

What are other drugs people take besides Contac 12 hour? *

What are other side effects people have besides Visual acuity reduced? *

Memory Loss: 14 people, 63.64%
Emotional Distress: 9 people, 40.91%
Fatigue (feeling of tiredness): 8 people, 36.36%
Stroke (sudden death of a portion of the brain cells due to a lack of oxygen): 8 people, 36.36%
Injury: 7 people, 31.82%
Anhedonia (inability to experience pleasure from activities usually found enjoyable): 7 people, 31.82%
Speech Impairment (Adult) (inability to speak (adult)): 6 people, 27.27%
Headache (pain in head): 5 people, 22.73%
Haemorrhagic Stroke (stroke caused by the rupture of a blood vessel in the brain): 4 people, 18.18%
Stress And Anxiety: 4 people, 18.18%

What are the existing conditions these people have? *

Nasopharyngitis (inflammation of the nasopharynx): 7 people, 31.82%
Hypersensitivity: 2 people, 9.09%
Sinus Congestion (blockage of sinus): 1 person, 4.55%
Influenza Like Illness: 1 person, 4.55%

* Approximation only. Some reports may have incomplete information.

Do you take Contac 12 hour and have Visual acuity reduced?

- Check whether Visual acuity reduced is associated with a drug or a condition
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Related studies:

Effectiveness of, long term effects of, and alternative drugs to Contac 12 hour:

Contac 12 hour (1,137 reports)

Visual acuity reduced treatments and more:

Visual acuity reduced (45,479 reports)

How severe was Visual acuity reduced and when was it recovered:

Visual acuity reduced in Contac 12 hour

Expand to all the drugs that have ingredients of chlorpheniramine maleate; phenylpropanolamine hydrochloride:

Visual acuity reduced and drugs with ingredients of chlorpheniramine maleate; phenylpropanolamine hydrochloride

Sub-studies by gender and age:

Female: 0-1 2-9 10-19 20-29 30-39 40-49 50-59 60+

Male: 0-1 2-9 10-19 20-29 30-39 40-49 50-59 60+

Browse all side effects of Contac 12 hour:

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 Visual acuity reduced:

Visual acuity reduced (1,493 drugs)

Browse all the conditions that are associated with Visual acuity reduced:

Visual acuity reduced (1,887 conditions)

How the study uses the data?

The study uses data from the FDA. It is based on chlorpheniramine maleate; phenylpropanolamine hydrochloride (the active ingredients of Contac 12 hour) and Contac 12 hour (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.