Barton, D.L., Wos, E.J., Qin, R., Mattar, B.I., Green, N.B., Lanier, K.S., . . . Loprinzi, C.L. (2011). A double-blind, placebo-controlled trial of a topical treatment for chemotherapy-induced peripheral neuropathy: NCCTG trial N06CA. Supportive Care in Cancer, 19, 833–841.

The purpose of this study was to evaluate a compounded topical gel containing baclofen 10 mg, amitriptyline HCL 40 mg, and ketamine 20 mg in a pluronic lecithin organogel (BAK-PLO).
 

Participants were randomized to receive 1.31 g of a compounded gel containing 10 mg of baclofen, 40 mg of amitriptyline HCL, and 20 mg of ketamine versus an identical looking placebo gel. Instructions were to apply one level spoonful of gel topically to each area of pain, numbness, and/ or tingling, twice a day (in the morning and before bed), for four weeks duration. Participants were not allowed to treat more than four areas of pain, numbness, and/or tingling at a single time (i.e., a maximum of four spoonfuls of gel per application). A small subset of participants was asked to have blood drawn at the end of the four weeks to measure concentrations of drugs and their metabolites.

• A total sample size of 203 patients (62% female) were assigned to either an intervention group or control group.
• The mean age of the intervention group was 59.9 years (SD = 10.75) and 62.1 years (SD = 10.27) in the control group; the age difference was not statistically significant.
• Disease characteristics were not provided, although it was clear that the patients had cancer.
• About 90% of the participants were Caucasian with chronic neuropathic pain for more than three months in duration.

The study was conducted at 16 separate academic institutions in the United States.

Phase of care

• Active treatment  

Applications

• Late effects and survivorship
   

The study was a double-blind, randomized, placebo-controlled trial.

• The European Organisation for the Research and Treatment of Cancer QLQ-C30 to measure quality of life.
• The CIPN20 to measure peripheral neuropathy.
• The Brief Pain Inventory to measure pain.
• The Profile of Mood States to measure mood.
• The National Cancer Institute's Common Terminology Criteria for Adverse Events.

Significant improvements in neuropathy symptoms in the hand and functioning of the hands were identified. Results in the feet were not as marked. Systemic absorption was minimal. Analysis of change in sensory neuropathy showed an effect size of about 0.28 (Cohen’s d, p = 0.053) in favor of the intervention. For the measurement subscale for motor neuropathy, the effect size of the change from baseline was 0.38 (p = 0.021). When analyzed as an ordinal scale outcome variable of negative change, no change or positive change for neuropathy symptoms, no significant difference was found between groups. No differences were noted between groups in the mood, pain, or quality-of-life measures.

Topical application of baclofen, 40 mg of amitriptyline HCL, and 20 mg of ketamine may be a useful approach to treatment of neuropathic pain related to CIPN, particularly if pain in the hands exists.

A limitation of this research was that the authors could not get U.S. Food and Drug Administration approval for the doses they originally wanted to use because of limited data on systemic absorption.

 Nurses may consider use of this novel topical compound, but more data is needed before definite recommendations can be made.