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Diphenhydramine (Benadryl)
Diphenhydramine blocks histamine H1 receptors, preventing histamine-mediated allergic and inflammatory responses.
Diphenhydramine blocks histamine H1 receptors, preventing histamine-mediated allergic and inflammatory responses. Used for Allergic reactions and urticaria, Pruritus, Motion sickness.
At a glance
| Generic name | Diphenhydramine (Benadryl) |
|---|---|
| Sponsor | United States Army Institute of Surgical Research |
| Drug class | First-generation H1 receptor antagonist |
| Target | H1 receptor |
| Modality | Small molecule |
| Therapeutic area | Allergy/Immunology |
| Phase | FDA-approved |
Mechanism of action
Diphenhydramine is a first-generation antihistamine that crosses the blood-brain barrier and antagonizes H1 receptors throughout the body and central nervous system. By blocking histamine binding, it reduces symptoms of allergic reactions, itching, and inflammation, while also producing sedation due to central H1 receptor antagonism.
Approved indications
- Allergic reactions and urticaria
- Pruritus
- Motion sickness
- Insomnia
- Parkinsonism
Common side effects
- Drowsiness/sedation
- Dry mouth
- Dizziness
- Headache
- Anticholinergic effects (urinary retention, constipation)
Key clinical trials
- Study to Evaluate the Effect of Repotrectinib on the Drug Levels of Transporter and CYP P450 Probe Substrates in Healthy Adult Participants (PHASE1)
- Trial of Diphenhydramine for Sleep in Children With Autism (PHASE2)
- Trial of Zolpidem for Sleep in Children With Autism (PHASE2)
- Sacituzumab Tirumotecan (MK-2870) in Combination With Pembrolizumab Versus Pembrolizumab Alone in Metastatic Non-small Cell Lung Cancer (NSCLC) With Programmed Cell Death Ligand 1 (PD-L1) Tumor Proportion Score (TPS) ≥ 50% (MK-2870-007) (PHASE3)
- The Effect of Losartan on Cephalexin (PHASE1)
- Case-Control Study of Pesticides and Childhood Leukemia
- A Study of Daratumumab, Carfilzomib, Lenalidomide, and Dexamethasone in Patients With Newly-Diagnosed Multiple Myeloma (PHASE2)
- Efficacy of Flurbiprofen Spray for Postoperative Sore Throat Following Double-Lumen Endobronchial Intubation (NA)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
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