Diphen and Cayston drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Diphen (diphenhydramine hydrochloride) and Cayston (aztreonam). Common drug interactions include surgery among females and pneumonia among males.

The phase IV clinical study analyzes what interactions people have when they take Diphen and Cayston. It is created by eHealthMe based on reports of 49 people who take the same drugs from the FDA, and is updated regularly.

What is Diphen?

Diphen has active ingredients of diphenhydramine hydrochloride. It is often used in insomnia. eHealthMe is studying from 115,432 Diphen users. Check the latest studies of Diphen.

What is Cayston?

Cayston has active ingredients of aztreonam. It is often used in cystic fibrosis. eHealthMe is studying from 5,310 Cayston users. Check the latest studies of Cayston.

On Aug, 05, 2026

49 people who take Diphen and Cayston together, and have interactions are studied.

What are the common drug interactions of Diphen and Cayston, by gender? *:

female:

Surgery
Tendonitis (a condition that causes pain and swelling of tendons)
Infective pulmonary exacerbation of cystic fibrosis (severe infective lung disease with production of abnormally thick mucus)
Headache (pain in head)
Nausea (feeling of having an urge to vomit)
Fatigue (feeling of tiredness)
Infusion site erythema (reddening of the skin at infusion site)
Infusion site swelling
Rash
Hypersomnia (excessive daytime sleepiness (eds))

male:

Pneumonia
Infective pulmonary exacerbation of cystic fibrosis (severe infective lung disease with production of abnormally thick mucus)
Urticaria (rash of round, red welts on the skin that itch intensely)
White blood cell count increased
Bronchiectasis (abnormal widening of the bronchi or their branches, causing a risk of infection)
Chest discomfort
Dyspnoea (difficult or laboured respiration)
Productive cough
Pseudomonas test positive
Sputum discoloured

What are the common drug interactions of Diphen and Cayston, by age (0-1 to 60+)? *:

0-1:

n/a

2-9:

Bacterial infection
Infusion site erythema (reddening of the skin at infusion site)
Infusion site swelling
Iron deficiency anaemia
Rash

10-19:

Gastrointestinal disorder (functional problems of gastrointestinal tract)
Gestational diabetes (diabetes in pregnancy)
Ileus (a painful obstruction of the ileum or other part of the intestine)
Ill-defined disorder
Polyhydramnios (excess of amniotic fluid in the amniotic sac)
Road traffic accident
Surgery
Infective pulmonary exacerbation of cystic fibrosis (severe infective lung disease with production of abnormally thick mucus)
Pneumonia
Alanine aminotransferase increased

20-29:

Chills (felling of cold)
Fatigue (feeling of tiredness)
Infective pulmonary exacerbation of cystic fibrosis (severe infective lung disease with production of abnormally thick mucus)
Headache (pain in head)
Infection
Infusion related reaction
Pain
Pneumonia
Pseudomonas infection (pseudomonas infection is caused by a bacterium, pseudomonas aeruginosa)
Urinary tract infection

30-39:

Death
Heart rate increased
Hypertension (high blood pressure)
Infective pulmonary exacerbation of cystic fibrosis (severe infective lung disease with production of abnormally thick mucus)
Pneumonia aspiration (bronchopneumonia that develops due to the entrance of foreign materials into the bronchial tree)
Pulmonary oedema (fluid accumulation in the lungs)
Ear pain
Headache (pain in head)
Hospitalisation
Pneumonia

40-49:

Abdominal pain upper
Headache (pain in head)
Pain

50-59:

Arthralgia (joint pain)
Asthenia (weakness)
Tendonitis (a condition that causes pain and swelling of tendons)
Cough
Dyspnoea (difficult or laboured respiration)
Fatigue (feeling of tiredness)
Pseudolymphoma (group of disorders having a benign course but exhibiting clinical and histological features suggestive of malignant lymphoma)
Pyrexia (fever)
Respiratory tract congestion (blockage on respiratory system)
Respiratory tract infection

60+:

n/a

What are the existing conditions these people have? *

Infective Pulmonary Exacerbation Of Cystic Fibrosis (severe infective lung disease with production of abnormally thick mucus): 6 people, 12.24%
Cough: 6 people, 12.24%
Wheezing (a high-pitched whistling sound made while you breath): 5 people, 10.20%
Bacterial Infection: 5 people, 10.20%
Bronchiectasis (abnormal widening of the bronchi or their branches, causing a risk of infection): 5 people, 10.20%
Dyspnea (difficult or laboured breathing): 5 people, 10.20%
Immunodeficiency Common Variable: 5 people, 10.20%
Immunodeficiency: 5 people, 10.20%
Pain: 5 people, 10.20%
Jock Itch (fungal infection of the groin and upper thighs): 4 people, 8.16%

* Approximation only. Some reports may have incomplete information.

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