Iressa and Benadryl drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Iressa (gefitinib) and Benadryl (diphenhydramine hydrochloride). Common drug interactions include fatigue among females and death among males.

The phase IV clinical study analyzes what interactions people have when they take Iressa and Benadryl. It is created by eHealthMe based on reports of 16 people who take the same drugs from the FDA, and is updated regularly.

What is Iressa?

Iressa has active ingredients of gefitinib. eHealthMe is studying from 10,102 Iressa users. Check the latest studies of Iressa.

What is Benadryl?

Benadryl has active ingredients of diphenhydramine hydrochloride. It is often used in allergies. eHealthMe is studying from 104,955 Benadryl users. Check the latest studies of Benadryl.

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, 26, 2026

16 people who take Iressa and Benadryl together, and have interactions are studied.

What are the common drug interactions of Iressa and Benadryl, by gender? *:

female:

Fatigue (feeling of tiredness)
Interstitial lung disease
Hypoxia (low oxygen in tissues)
International normalised ratio increased
Performance status decreased
Pulmonary embolism (blockage of the main artery of the lung)
Atelectasis (partial or complete collapse of the lung)
Bronchiectasis (abnormal widening of the bronchi or their branches, causing a risk of infection)
Contusion (a type of hematoma of tissue in which capillaries)
Cystitis haemorrhagic (blood in the urine and painful voiding)

male:

Death
Rash
Nodule (a growth of abnormal tissue)
Constipation
Disease progression
Dysphagia (a condition in which swallowing is difficult or painful)
Dyspnoea (difficult or laboured respiration)
Febrile neutropenia (fever with reduced white blood cells)
Hallucination (an experience involving the perception of something not present)
Increased upper airway secretion

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

0-1:

n/a

2-9:

n/a

10-19:

Dysphagia (a condition in which swallowing is difficult or painful)
Hallucination (an experience involving the perception of something not present)
Respiratory arrest (cessation of normal respiration due to failure of the lungs to function effectively)

20-29:

n/a

30-39:

n/a

40-49:

Death
Malignant pleural effusion (a condition in which cancer causes an abnormal amount of fluid to collect between the thin layers of tissue lining of lung)

50-59:

Constipation
Splenic infarction (tissue damage of spleen)

60+:

Interstitial lung disease
Pleural effusion (water on the lungs)
Diarrhoea
Gilbert's syndrome (liver condition in which the liver doesn't properly process a substance called bilirubin)
Hepatic enzyme increased
Malignant neoplasm progression (cancer tumour came back)
Nodule (a growth of abnormal tissue)
Atelectasis (partial or complete collapse of the lung)
Bronchiectasis (abnormal widening of the bronchi or their branches, causing a risk of infection)
Cystitis haemorrhagic (blood in the urine and painful voiding)

What are the existing conditions these people have? *

Lung Cancer - Non-Small Cell (lung cancer): 5 people, 31.25%
Lung Neoplasm Malignant (cancer tumour of lung): 2 people, 12.50%
Breast Cancer Metastatic: 2 people, 12.50%
Breast Cancer Male: 2 people, 12.50%
Tracheal Cancer (cancer of trachea): 1 person, 6.25%
Renal Cell Carcinoma (a kidney cancer): 1 person, 6.25%
Papilloma (small, noncancerous (benign) tumour): 1 person, 6.25%
Malignant Respiratory Tract Neoplasm (cancer tumour of respiratory tract): 1 person, 6.25%
Hypopharyngeal Cancer: 1 person, 6.25%
High Blood Pressure: 1 person, 6.25%

* Approximation only. Some reports may have incomplete information.

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