Trigeminal neuralgia is a paroxysmal extreme pain that occurs in the region dominated by facial trigeminal nerve. It is characterized by repetition and irregularity. Once the disease occurs, the pain is generally unbearable. Carbamazepine or other drugs is the main treatment methods. However, most patients will experience side effects so that drug treatments for trigeminal neuralgia has its limitation limitation. Surgical treatments have better efficacy but with greater risk.~The efficacy of acupuncture for pain treatment has been widely demonstrated by many clinical trials. A recent meta analysis has demonstrated that significant differences of efficacy between true and sham acupuncture indicate that acupuncture is more than a placebo. However, there are few clinical randomized controlled trials reporting the efficacy of acupuncture on trigeminal neuralgia.~Histamine H1 receptor antagonists are commonly used for treating allergy. Recently, we found that histamine H1 receptor antagonists at relatively low doses facilitate electroacupuncture (EA) analgesia in the acetic acid-induced abdominal writhing test. We have also conducted a clinical trial to demonstrate that H1 receptor antagonists facilitate EA analgesia in healthy volunteers. The study recruited 40 healthy normal subjects we found that EA at bilateral ST36 and GB34 plus high-dose dexchlorpheniramine (4 mg) produced greater pain threshold increases as than EA alone groups, suggesting the combination use of H1 antihistamine can facilitate acupuncture analgesia in humans.~This study aims to investigate whether antihistamine dexchlorpheniramine can also facilitate the analgesic effect of acupuncture in patients with trigeminal neuralgia. The experimental design is as follows: This experiment will recruit 40 healthy subjects, randomly divided into 4 groups, each group of 10 patients (1) sham acupuncture + placebo tablet group, (2) true acupuncture + placebo tablet group , (3) true acupuncture + antihistamine group and (4) sham acupuncture + antihistamine group. The treatment duration is one week for 3 acupuncture/sham acupuncture treatment. Dexchlorpheniramine (4 mg) or placebo tablets will be administered at the sleeping time the day before acupuncture treatment.
Trigeminal neuralgia is a paroxysmal extreme pain and is an unmet clinical need, we hope that our discovery about the antihistamine and acupuncture can be used in the treatment trigeminal neuralgia. This present study aims to further investigate whether antihistamine dexchlorpheniramine can facilitate the analgesic effect of acupuncture in patients with trigeminal neuralgia.