Neuropathic Pain Caused by Radiation Therapy

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