Lidocaine vs Diphenhydramine for Skin Lacerations

Age: 18+

Sex: Any

Trial Phase: Phase 3

Sponsor: Florida Atlantic University

Disqualifiers: Active bleeding, Complex lacerations, Allergies, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 2

Duration: 1 day

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines whether diphenhydramine (an antihistamine) is as effective as lidocaine (a local anesthetic) for numbing small skin cuts that require stitches. Although lidocaine is the standard choice, diphenhydramine might serve as a viable alternative. The trial will compare the pain experienced during and after stitching with each treatment. It is suitable for individuals with simple cuts needing one layer of stitches, treatable by emergency room doctors. Those with allergies to these medications or with more complex cuts are not eligible. As a Phase 3 trial, it represents the final step before FDA approval, allowing participants to potentially expand treatment options.

Will I have to stop taking my current medications?

The trial protocol does not specify whether you need to stop taking your current medications.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that diphenhydramine can be safely injected under the skin. However, some people report skin issues at the injection site, such as skin damage, and the injection can be painful. It may also cause drowsiness afterward. Studies indicate that diphenhydramine numbs small cuts as effectively as lidocaine, but it might be more painful when injected.

Lidocaine, in contrast, is commonly used for numbing during many procedures and is generally well-tolerated. It effectively relieves pain and is safely used for treating open wounds. However, in rare cases, it can cause serious side effects, such as acute toxicity, which can be dangerous.

Both treatments have been used before, but each has pros and cons regarding safety. These details are important to consider when deciding to join a clinical trial. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about these treatments because they offer potential alternatives to standard care for skin lacerations, which typically involves lidocaine as a local anesthetic. Diphenhydramine, commonly known as an antihistamine, is being explored for its anesthetic properties, which is quite different from its usual use for allergies. This alternative approach could provide pain relief for individuals who may have allergies or sensitivities to lidocaine, expanding options for patient care. Additionally, a new mechanism of action in using diphenhydramine for pain relief could lead to innovative methods in treating minor injuries.

What evidence suggests that this trial's treatments could be effective for skin lacerations?

This trial will compare the effectiveness of lidocaine and diphenhydramine for treating skin lacerations. Research has shown that lidocaine, a well-known local anesthetic, effectively relieves pain during procedures for simple cuts. Diphenhydramine, commonly used for allergies, has also been studied for its potential as a local anesthetic. One study found that 1% diphenhydramine and 1% lidocaine provided similar pain relief for up to 30 minutes after injection. However, diphenhydramine showed differences in effectiveness between 45 to 60 minutes and caused skin damage (tissue death) in one case. While lidocaine remains a reliable choice, diphenhydramine could serve as an alternative, but further research is needed to understand its long-term safety and effectiveness. ^{6 7 8 9 10}

Are You a Good Fit for This Trial?

This trial is for individuals who come to the emergency department with simple lacerations that need only one layer of sutures and can be treated by emergency physicians. It's not suitable for those with complex wounds, active bleeding, allergies to lidocaine or diphenhydramine, or if their repair would benefit from epinephrine.

Inclusion Criteria

My cut can be treated by emergency doctors.

I have cuts that needed stitches.

Exclusion Criteria

I am currently bleeding from a cut.

My cut needs to be treated by a specialist.

Patients with allergies to either diphenhydramine or lidocaine

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1 week

Treatment

Participants receive either lidocaine or diphenhydramine for local anesthesia during laceration repair

1 day

1 visit (in-person)

Follow-up

Participants are monitored for satisfaction and sensation reduction immediately after the procedure

Immediately after procedure

1 visit (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Diphenhydramine
• Lidocaine

Trial Overview The study compares two local anesthetics: Lidocaine and Diphenhydramine. Patients will receive one of these drugs before their laceration is sutured. The goal is to see if Diphenhydramine's effectiveness in numbing pain is as good as Lidocaine's during the procedure.

How Is the Trial Designed?

Group I: Diphenhydramine Experimental Treatment 1 Intervention

Group II: Lidocaine Active Control 1 Intervention

Who Is Running the Clinical Trial?

Florida Atlantic University

Lead Sponsor

Trials

35

Recruited

10,700+

Baptist Health South Florida

Collaborator

Trials

54

Recruited

8,100+

Published Research Related to This Trial

Buffered lidocaine with epinephrine and plain lidocaine with epinephrine were found to be more effective anesthetics for suturing minor lacerations compared to buffered lidocaine alone and diphenhydramine with epinephrine, based on evaluations from both patients and physicians.

Diphenhydramine with epinephrine was significantly more painful to inject than buffered lidocaine or buffered lidocaine with epinephrine, indicating it may not be the best choice for pain management in this context.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison trial of four injectable anesthetics for laceration repair. Ernst, AA., Marvez-Valls, E., Nick, TG., et al.[2019]

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/8363115/

Double-blinded comparison of diphenhydramine versus ... Results: No significant differences in mean pinprick sensation were seen from baseline to 30 minutes. Significant differences were seen at 45 (P = .036) and 60 ...

2. qscience.com qscience.com/content/journals/10.5339/jemtac.2025.15?crawler=true&mimetype=application/pdf

Comparison of different delivery methods of lidocaine and ... The same study also reported that diphenhydramine caused skin necrosis in one subject, a side effect that was not observed with lidocaine.

3. europepmc.org europepmc.org/article/med/8483174

Lidocaine versus diphenhydramine for anesthesia in the ... This prospective study compared the effectiveness of 1% diphenhydramine with 1% lidocaine for local anesthesia in repair of minor skin lacerations in adults ...

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11404102/

Rationale for the topical use of a combination ... Combination of antihistamines and fast-acting analgesics may help to reduce discomfort associated with cutaneous reactions. Aim. To evaluate efficacy and safety ...

5. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0196064494703604

1% Lidocaine Versus 0.5% Diphenhydramine for Local ... The data were analyzed after 98 lacerations were included in the study. Fifty patients received 0.5% diphenhydramine, and 48 received 1% lidocaine. Two patients ...

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/27625354/

Safe Use of Subcutaneous Diphenhydramine in the ... This retrospective review demonstrates that subcutaneous diphenhydramine injection is a safe alternative to oral and other parenteral routes.

7. clinicalradiologyonline.net clinicalradiologyonline.net/article/S0009-9260(22)00693-6/fulltext

Safety and technical success of diphenhydramine as an ... Potential reported disadvantages of DPH include skin necrosis at the injection site, painful administration, and drowsiness. 17. Bartfield ...

8. ncbi.nlm.nih.gov ncbi.nlm.nih.gov/books/NBK526010/

Diphenhydramine - StatPearls - NCBI Bookshelf - NIH However, limited data on its safety and dosing in ESKD are available. High protein binding may hinder its removal during dialysis, raising ...

9. sciencedirect.com sciencedirect.com/science/article/abs/pii/0736467989900061

Use of diphenhydramine for local anesthesia in “caine” One subject developed skin necrosis at the injection site with diphenhydramine. The duration of local anesthesia for 1% lidocaine was significantly longer and ...

10. annemergmed.com annemergmed.com/article/S0196-0644(94)70360-4/abstract

1% Lidocaine Versus 0.5% Diphenhydramine for Local ... 1% diphenhydramine is as effective as 1% lidocaine for anesthesia in minor laceration repair, but that it also is more painful to inject.