Efficacy and Long-Term Safety of Ibuprofen Gargle for Oral Lichen Planus: A Study Protocol of Randomized Crossover and Long-Term Extension Trials

Oral lichen planus (OLP) is a type of chronic and refractory stomatitis characterized by abnormal keratinization, which is often painful. There is no consensus regarding treatment options for OLP, particularly in the presence of pain. The current study protocol focuses on the short-term efficacy and long-term safety of an ibuprofen gargle for pain management in patients with OLP. Patients (n = 24) with painful OLP will be enrolled. During a crossover study period, patients in the ibuprofen–placebo (IP) group will receive an ibuprofen gargle (0.6%) on day 1, a placebo gargle on day 2, and an ibuprofen gargle on days 3–5 at least once daily. Patients in the placebo–ibuprofen (PI) group will receive a placebo gargle on day 1, an ibuprofen gargle on day 2, and an ibuprofen gargle on days 3–5 at least once daily. The primary endpoint of the crossover study period is the change in pain level as measured by a visual analogue scale score from before gargle administration to 5 min after gargle administration on days 1 and 2. The primary endpoint of the long-term extension study is assessment of long-term safety. The results of this study may support existing evidence regarding the effectiveness of ibuprofen rinses in treating OLP.