Recruiting
Phase 3

Lidocaine with Benzathine Penicillin G

Sponsor:

Washington University School of Medicine

Code:

NCT06391125

Conditions

Syphilis Infection

Benzathine Penicillin Adverse Reaction

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Accepted

Interventions

normal Saline

Lidocaine

Study Details

Brief summary:

There is evidence to suggest that lidocaine can help reduce the pain associated with intramuscular injections of benzathine penicillin G (BPG) or Bicillin, used to treat syphilis infections. A study published in the Journal of Family Practice in 2001 compared the pain experienced during bicillin injections with and without the use of lidocaine. The study found that patients who received lidocaine injections before receiving bicillin reported significantly less pain compared to those who received bicillin injections without lidocaine. Per the International Union against Sexually Transmitted Infections (IUSTI) European Guidelines for syphilis management, lidocaine has been used as a diluent for BPG since 1998. In the United States (US), BPG often comes prepackaged and lidocaine is unable to be used as a diluent with the same ease as it is in Europe. In light of this, the investigators propose a randomized controlled trial of benzathine penicillin G with and without lidocaine to quantify any site pain reduction with lidocaine in patients being treated for syphilis.

This study is a randomized, double blinded, placebo controlled trial. During this study, patients needing BPG treatment for syphilis will be screened for any penicillin allergies and consented to their participation. Each participant will receive 2 injections of BPG, 1.2 million units each (2x1.2 million units = 2.4 million units, the standard dose for syphilis treatment), as intramuscular injections, one in each gluteal muscle, with one of the injections randomly having 0.5ml of 1% lidocaine added while the other has 0.5 ml normal saline solution. The side of each injection will be randomized by the medical assistant (MA)/nurse filling the vials and the injecting MA will be blinded, as well as the study participant, as to which vial contains lidocaine and which contains normal saline. The participants will then be asked to rate their pain from 0-10 on each site of injection at 10 minutes post injection, then again at 24 hours after injection via email electronic survey (via RedCap). The differences in pain from the two injections will be compared and analyzed to see if lidocaine reduces pain associated with BPG injections compared to the control of normal saline added to BPG.

Conditions

Syphilis Infection

Benzathine Penicillin Adverse Reaction

Study ID

NCT06391125

Start date

Jul 1, 2024

Status verified date

Mar, 2025

Completion date

Dec, 2025

Anticipated

Primary completion date

Dec, 2025

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Accepted

Inclusion Criteria:

  • Adults 18 years of age or above
  • Confirmed syphilis diagnosis (reactive RPR with confirmatory treponemal testing)
  • Receiving first injection in series if patient requires 3x weekly injections for syphilis treatment

Exclusion Criteria:

  • Penicillin allergy (anaphylaxis)
  • Lidocaine allergy (anaphylaxis)
  • Second or third injection in series if patient requires 3x weekly injections for syphilis treatment
  • Pregnancy

Study Design

Enrollment

48 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Lidocaine + Benzathine Penicillin G Arm

0.5ml 1% lidocaine solution added to prefilled 1.2 million units Benzathine Pencillin G syringe which will be injected once into the gluteal muscle of the study participant, the side (left or right) to be randomly assigned with the control assigned to the other gluteal muscle.

placebo comparator: Normal Saline + Benzthine Penicillin G Arm

0.5ml normal saline solution added to prefilled 1.2 million units Benzathine Pencillin G syringe which will be injected once into the gluteal muscle of the study participant, the side (left or right) to be randomly assigned with the study arm assigned to the other gluteal muscle.

Interventions

normal Saline

0.5ml normal saline solution added to prefilled 1.2 million units Benzathine Pencillin G syringe

Lidocaine

0.5ml 1% lidocaine solution added to prefilled 1.2 million units Benzathine Pencillin G syringe

Primary outcome measure

  • Mean Pain Score (0-10) of Benzathine Penicillin G + Lidocaine Injection 10 minutes post injection [ Time Frame: 10 minutes ]
  • Mean Pain Score (0-10) of Benzathine Penicillin G + Saline Injection 10 minutes post injection [ Time Frame: 10 minutes ]
  • Relative difference of mean pain scores between injection types 10 minutes post injection [ Time Frame: 10 minutes ]
  • Mean Pain Score (0-10) of Benzathine Penicillin G + Lidocaine Injection 24 hours post injection [ Time Frame: 24 hours ]
  • Mean Pain Score (0-10) of Benzathine Penicillin G + Saline Injection 24 hours post injection [ Time Frame: 24 hours ]
  • Relative difference of mean pain scores between injection types at 24 hours post injection [ Time Frame: 24 hours ]

Central Contacts and Locations

Central contacts

Joseph Cherabie, MD

7202858096jcherabie@wustl.edu

Locations

WashU Infectious Diseases Clinic

Recruiting

Saint Louis, Missouri, United States, 63110

Contacts

Joseph N Cherabie, MD

314-362-7827jcherabie@wustl.edu

Principal Investigator:

Joseph N Cherabie, MD

More Information

Sponsor

Washington University School of Medicine

Last update posted

Mar 25, 2025

Last verified

Mar, 2025

Keywords

  • Syphilis
  • Syphilis Treatment
  • Benzathine Penicillin G
  • Lidocaine

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Washington University School of Medicine on 2025-03-25.