Oral Topical Doxepin Rinse: Anesthetic Effect in Normal Subjects

Doxepin for Radiation Therapy-Induced Mucositis Pain in the Treatment of Oral Cancers

Radiotherapy (RT), an integral part of the oncologic treatment for patients with head and neck cancer, can cause adverse side effects such as oral mucositis (OM). Pain from OM can impact a patient’s quality of life and interrupt RT treatment schedules, which decreases the probability for achieving cancer cure. Conventionally, RT-induced OM pain is treated with analgesics and/or mouthwash rinses. Doxepin, a traditional tricyclic antidepressant with analgesic and anesthetic properties when applied topically to the mucosa, has been shown to lower OM pain in multiple single-arm trials (Epstein et al.) and more recently, in a placebo-controlled crossover study (Leenstra and Miller et al.). Currently, a placebo-controlled study (Sio and Miller et al.) using doxepin for esophagitis pain caused by RT to the thorax is underway. Doxepin will also be further compared with magic mouthwash and a placebo solution in a three-arm trial (Miller and Sio et al.) with head and neck cancer patients with OM pain caused by RT. Doxepin may represent a new standard for treating RT-induced OM pain in the future.

Doxepin rinse for management of mucositis pain in patients with cancer: one week follow-up of topical therapy

This study assessed the effectiveness of oral doxepin rinse for mucositis-related pain management in patients following 1 week of repeated dosing. Patients with oral mucositis due to head and neck radiation therapy or hematopoietic stem cell transplant (HSCT) were recruited to participate in a 1-week follow-up study. Subjects who gave informed consent rinsed with doxepin (5 ml) during the initial visit and were then told to use doxepin rinse over the next week as needed, three to six times per day, and return for a follow-up visit. At each visit, mucositis was scored using the Oral Mucositis Assessment Scale and oral pain was assessed using a visual analogue scale before and after rinsing. The use of a systemic analgesic was recorded, and side effects were documented. At the follow-up visit, subjects were also asked to retrospectively report average pain scores they experienced over the past week, 5 and 15 minutes following rinse. Nine subjects were enrolled in the study. Statistically significant reductions in pain scores were reported for 2 hours following doxepin rinse during the initial visit (p < .05). Patients recalled that their pain significantly dropped within 5 minutes of rinsing over the week of repeated dosing (p < .05). At the follow-up visit, subjects reported statistically significant pain reduction 5 minutes after doxepin rinsing (p < .05). These results indicate that doxepin rinsing continues to produce reduced intensity of pain levels over a 1-week span of repeated dosing.

Multimodal approaches to the management of neuropathic pain: the role of topical analgesia

Because of their localized activity and low systemic absorption, topical analgesics have a favorable safety profile and a low risk for drug-drug interactions. There is a growing body of evidence on the efficacy and safety of these agents in a variety of pain disorders, including the most prevalent neuropathic pain conditions. The molecular basis for the usage of peripheral analgesics in neuropathic pain and the available clinical trial evidence for a wide variety of topical agents are reviewed.

Oral doxepin rinse: the analgesic effect and duration of pain reduction in patients with oral mucositis due to cancer therapy

This research expands on our prior study, in which we assessed pain reduction after topical doxepin rinse in patients with oral mucositis resulting from cancer and cancer therapy. We continued to enroll patients with painful oral mucositis attributable solely to cancer therapy and performed further analysis on the duration of pain reduction. Fifty-one patients with oral mucositis were enrolled. Mucositis was scored and oral pain was assessed with a visual analog scale before doxepin oral rinse (5 mg/mL) and at regular intervals up to 4 h after rinsing. Of those who reported pain reduction, 95% did so within 15 min of rinsing with doxepin. In the total sample, the average patient reported a 70% maximum decrease in pain (P < 0.0001). Recurrence of pain was slow and at the conclusion of the study 19 patients (37%) still reported a reduction from baseline pain. With this censored data we used Cox-proportional hazards to determine what variables best explained longer duration of pain reduction. Our final model determined that more severe baseline pain, worse mucosal erythema score, or a larger relative maximum reduction in pain were all associated with a slower rate of pain recurrence after oral rinsing (all P < 0.01).

Emerging approaches for prophylaxis and management of oropharyngeal mucositis in cancer therapy

Oral mucositis is a common treatment-limiting side effect of cancer therapy that may have a significant impact on quality of life and on the cost of care. Oral mucositis is the most distressing complication of cancer therapy as reported by head and neck cancer patients, in patients receiving dose-dense myelosuppressive chemotherapy and in patients receiving haematopoietic stem cell transplant. Mucositis may increase the risk of local and systemic infection, particularly in myelosuppressed patients. Severe oral mucositis can lead to the need to interrupt or discontinue cancer therapy, and thus may impact cure of the primary disease. Current care of patients with mucositis is essentially palliative, and includes appropriate oral hygiene, nonirritating diet and oral care products, topical palliative mouth rinses, topical anaesthetics and use of systemic opioid analgesics. Emerging approaches for prevention and treatment of oral mucositis are developing based on an increasing understanding of the pathobiology of mucosal damage and repair. New interventions are expected to be administered based on the mechanisms of initiation, progression and resolution of the condition. The approval by the FDA of keratinocyte growth factor (palifermin; Amgen) in 2004 represents a new step in prevention of oral mucositis in stem cell transplant patients based on the increasing understanding of the pathogenesis of mucositis. Progress in the prevention and management of mucositis will improve quality of life, reduce cost of care and facilitate completion of more intensive cancer chemotherapy and radiotherapy protocols. Improved management of mucositis may allow implementation of cancer treatment protocols that are currently excessively mucotoxic, but have potentially higher cure rates of the malignant disease.