LIMIT Trial Testing Lidocaine Addition to Benzathine Penicillin G Injections for Pain Reduction in Adults Treated for Syphilis

What this Trial Is About

Researchers are evaluating whether adding lidocaine to benzathine penicillin G injections can reduce pain for adults being treated for syphilis infections. This randomized, double-blinded, placebo-controlled trial aims to compare pain levels with and without lidocaine added to the injection. The study is motivated by previous evidence showing that lidocaine reduces injection pain, and it addresses the challenge of using lidocaine with prepackaged benzathine penicillin G syringes in the US. Participants will receive two intramuscular injections of benzathine penicillin G, each 1.2 million units, one in each buttock. One injection will include 0.5 ml of 1% lidocaine added to the prefilled syringe, while the other will have 0.5 ml of normal saline solution. The side for each injection is randomly assigned, and both participants and staff administering injections are blinded to which contains lidocaine or saline. Participants will rate their pain on a 0 to 10 scale at 10 minutes after each injection and again at 24 hours via an electronic survey. Researchers will compare pain scores between the two injection types to see if lidocaine reduces pain. They will also monitor for adverse reactions over 7 days and record any use of other pain medications within 24 hours. The study involves screening for allergies and includes adults beginning treatment for syphilis.

LIMIT Trial - Lidocaine With Intramuscular Injection of Benzathine Penicillin G for Treponema Pallidum Treatment