Neuropathic Pain Caused by Radiation Therapy

• Topical amitriptyline and ketamine and topical lidocaine alone have been shown to improve management of neuropathic pain in nonmalignant subjects. Anecdotal experience has shown improvement in use of all three topical drugs combined in radiation skin reactions. There currently is no research evidence for the use of all three compounded interventions. This study aims to target subjects with pain from radiation therapy who are not receiving adequate relief with standard interventions and may be eligible to receive this alternate intervention.
• Hypothesis:Topical AKL in PLO gel can effectively and safely reduce neuropathic pain experienced by patients with radiotherapy induced skin reactions.
• Justification: Standard treatment of painful radiation skin reactions such as moist desquamation consists of saline soaks, silver sulfadiazine and oral analgesics. However, sometimes the pain exceeds this standard intervention, patients are sulfa allergic or patients are intolerant to oral analgesics such as opioids. AKL in PLO gel is targeted for neuropathic pain and may be used alternatively to standard interventions. The participation rate will help to further estimate the feasibility of a larger sample size study to look at efficacy.

Inclusion criteria

• Age greater or equal to 18 years with ability to provide written informed consent.
• Subjects currently receiving radiation therapy or having completed radiotherapy in less than 4 weeks from study entry, who have developed skin reactions that are painful.
• Radiation skin reaction pain has qualities of burning as scored on UWNPS of 1 or more
• Skin toxicity Assessment Tool showing dry desquamation or worse
• Presence of objective dynamic allodynia and/or pinprick hyperalgesia as assessed by physician
• Subjects show less than 1 point decrease in UWNPS after 2 days of using standard intervention.
• Subjects are allergic or intolerant to standard intervention.
• Subjects must be available by telephone 2 and 6 weeks after RT treatment is completed.

Exclusion criteria

• Allergy to amitriptyline, ketamine or lidocaine
• Untreated severe major depression
• Ongoing use of monoamine oxidase inhibitor
• Pain from another source as severe or greater than the pain under study
• Evidence of another type of neuropathic pain not included in this study.
• Normal cognitive and communicative ability as judged by clinical assessment and ability to complete self-report questionnaires
• Not pregnant or breastfeeding