Diphenhydramine is named as an intervention in 7 current clinical trials in our USA, China, UK and Ireland registers. 1 is recruiting patients now. The most common phase is Phase 3. The sponsor with the most trials is Sanofi (3). The most-studied condition is Plasma Cell Myeloma.
Registers list studies that are recruiting, about to open, active but closed to enrolment, or enrolling by invitation. The UK and USA registers cover industry-sponsored studies only. Trial titles and statuses are copied from the registry as published.
The same active substance in our other registers, matched by its exact name. Each entry links to the register record it comes from.
1 single-substance product containing Diphenhydramine on the HPRA medicines list.
No entry for Diphenhydramine in the EMA, FDA or German BfArM shortage lists we track.
| Lead sponsor | Trials |
|---|---|
| Sanofi | 3 |
| Hoffmann-La Roche | 2 |
| Tianjin Medical University Cancer Institute and Hospital | 2 |
| Register | Trials | Recruiting |
|---|---|---|
| Clinical trials in USA | 5 | 1 |
| Clinical trials in China | 5 | 0 |
| Clinical trials in UK | 3 | 0 |
| Clinical trials in Ireland | 1 | 0 |
A trial with sites in more than one country appears in each of those registers.
7 current trials in our USA, China, UK and Ireland registers name Diphenhydramine as a drug or biological intervention, as of the registry sync on 25 September 2026. Completed and withdrawn studies are not counted.
Yes. 1 of the 7 trials is recruiting: 1 with sites in USA. Eligibility and site contacts are on each trial's record. Only the study team can confirm whether a patient is eligible.
Sanofi (3), Hoffmann-La Roche (2) and Tianjin Medical University Cancer Institute and Hospital (2). The number in brackets is how many trials each organisation leads.
Yes. The HPRA medicines list includes 1 single-substance product containing Diphenhydramine, for example Nytol One-A-Night 50 mg Tablets (Chefaro Ireland DAC,). A licence does not mean a product is currently marketed or reimbursed; see each product's record.
Not in the lists we track: Diphenhydramine has no entry in the EMA, FDA or German BfArM shortage registers as of their latest sync.
Every trial, status, phase and sponsor on this page is copied from public ClinicalTrials.gov records by a daily sync. Nothing here describes how Diphenhydramine works or whether it is effective, and it is not medical advice.
Everything on this page is copied from public ClinicalTrials.gov registry records โ it is not written from memory, and nothing here describes how Diphenhydramine works or whether it is effective. Each trial links to its own record so you can check it yourself.
This page is built automatically: a daily sync job reads the registry records behind our country trial registers, collects every trial that lists Diphenhydramine (or a registered synonym) as a drug or biological intervention, and tabulates the registry fields directly. Placebos and generic comparators are excluded. There is no AI drafting and no per-compound editorial pass, and the page has not been clinically reviewed. The “last verified” date above is the timestamp of that sync, not a review date. Our general editorial approach is described in our editorial standards and corrections policy. The ClinicalTrials.gov data on this page was last retrieved on 25 Sep 2026.