The mechanism of action by which amlexanox accelerates healing of aphthous ulcers is unknown. In vitro studies have demonstrated amlexanox to be a potent inhibitor of the formation and/or release of inflammatory mediators (histamine and leukotrienes) from mast cells, neutrophils and mononuclear cells. Given orally to animals, amlexanox has demonstrated anti-allergic and anti-inflammatory activities and has been shown to suppress both immediate and delayed type hypersensitivity reactions. The relevance of these activities of amlexanox to its effects on aphthous ulcers has not been established.
Pharmacokinetics and Metabolism
After a single oral application of 100 mg of paste (5 mg amlexanox), maximal serum levels of approximately 120 ng/ml are observed at 2.4 hours. Most of the systemic absorption of amlexanox is via the gastrointestinal tract, and the amount absorbed directly through the active ulcer is not a significant portion of the applied dose. The half-life for elimination was 3.5 +/- 1.1 hours in healthy individuals. Approximately 17% of the dose is eliminated into the urine as unchanged amlexanox, a hydroxylated metabolite, and their conjugates. With multiple applications four times daily, steady state levels were reached within one week, and no accumulation was observed with up to four weeks of usage.
The safety of amlexanox oral paste, 5%, was established in a study in which 100 patients with aphthous ulcers applied the medication four times daily for 28 days with no significant topical or systemic adverse effects. The effectiveness was demonstrated in three controlled clinical studies of patients with mild to moderate aphthous ulcers which evaluated 464 patients receiving amlexanox oral paste, 5%, 465 patients receiving a placebo paste, and 195 patients receiving no treatment. Amlexanox oral paste, 5%, was shown to accelerate healing of aphthous ulcers in a statistically significant manner as compared to both vehicle and no treatment.
Amlexanox oral paste, 5%, versus no treatment
In the combined database of the two studies including a no treatment group, there was a significant difference in the rate of ulcer healing which translated to a reduction of 1.6 days in the median time to complete healing and a reduction of 1.3 days in the median time to complete pain relief. After 3 days of treatment there was a significant difference in both percent of patients with complete healing of ulcers (21% vs. 8%) and percent of patients with complete resolution of pain (44% vs. 20%).
Amlexanox oral paste, 5%, versus vehicle
In the combined database of the three studies, there was a significant difference in the rate of ulcer healing which translated into a reduction of 0.7 days in the median time to complete healing, and a reduction of 0.7 days in the median time to complete pain relief. After 4 days of treatment there was a significant difference in both percent of patients with complete healing of ulcers (37% vs. 27%) and percent of patients with complete resolution of pain (60% vs. 49%).
Pain relief occurred in conjunction with healing of the ulcers. Amlexanox oral paste, 5%, by itself, was not shown to be an analgesic medication. The safety and effectiveness of the product in immunocompromised individuals has not been assessed.
Results for amlexanox, 5%, vs. vehicle are based on three clinical trials.
Results for amlexanox, 5%, vs. no treatment are based on two clinical trials.
* denotes statistically significant superiority of amlexanox, 5%, vs. vehicle and no treatment.
# denotes statistically significant superiority of amlexanox, 5%, vs. no treatment.
Error bars represent Standard Error of the Mean.
Last reviewed on RxList: 6/2/2009
This monograph has been modified to include the generic and brand name in many instances.
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