BACKGROUND: Rheumatic fever (RF) and Rheumatic heart disease (RHD) patients Rheumatic Heart Disease (RHD) patients necessitate secondary prophylaxis with benzathine penicillin G (BPG) injection every 3 weeks to prevent recurrences and complications. Patients with rheumatic fever on regular benzathine penicillin G injection usually experience moderate to severe pain resulting to poor compliance to treatment. 

OBJECTIVES: This study aims to compare the effect of BPG diluted in lidocaine hydrochloride 1%  versus diluted water in reducing injection pain in patients with RF and RHD.

METHODS: This is a randomized double-blind crossover study conducted at the PCMC OPD. Thirty-three patients diagnosed with RF and RHD were divided into 2 groups; the first group received BPG diluted in sterile water followed by BPG diluted in lidocaine hydrochloride  1% after 21 days, the second group received the same medication in reverse order. Pain scale was measured using Universal pain assessment tool immediately after injection. Paired T test was used to compare the pain score results of the two groups.

RESULTS: Pain score was significantly less in patients who received BPG diluted in lidocaine hydrochloride 1%; from an average pain score of 4.88 to 0.63 (p<0.0001), among those who received BPG diluted in sterile water. No adverse effects were seen in all patients.

CONCLUSION: This study concluded that BPG diluted in lidocaine hydrochloride 1% significantly and safely reduced post-injection pain. In all patients diagnosed with RF and RHD, BPG injection should be diluted in lidocaine hydrochloride 1% to decrease injection pain and improve patient's compliance.