Clinical trial NCT02484170: Mannitol Cream for Post Herpetic Neuralgia
Official title: Mannitol Cream in the Treatment of Post-herpeticNeuralgia;a Randomized Placebo-Controlled Crossover Pilot Study
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE1
PHASE2
Conditions: Neuralgia, Postherpetic
Keywords: Mannitol
cream
neuropathic pain
Lead sponsor: University of British Columbia
Sponsor class: OTHER
First posted: 2015-06-29
Enrollment: 20
Sex: ALL
Minimum age (years): 19
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: 1 week observation, one week cream A assigned, 3 day crossover, one week of cream B assigned. After the crossover study, 3 months of mannitol cream assigned.
Primary purpose: TREATMENT

Brief summary: 30% mannitol cream has shown its ability to reduce the activation of the Capsaicin (TRPV1) (Transient Receptor Potential Vanilloid 1) receptor, a likely cause of the pain of post-herpetic neuralgia (PHN). This randomized placebo-controlled crossover study compares PHN pain one week before, for one week on the randomly assigned mannitol versus placebo cream and, after a three day washout, for one week on the other cream. Following this crossover study, participants receive mannitol cream for three months. Pain levels will be checked to assess whether continued use of this cream significantly reduces the pain levels associated with PHN. If pain persists beyond 3 months, participants will be offered mannitol and menthol cream for one month following which their pain levels will be checked.

Detailed description: Pain levels: 0 to 10 Numerical Rating Scale (NRS), medication and alcohol intake will be checked daily for one week prior to randomization in 20 participants with post herpetic neuralgia, lasting more than three months. Following this 10 will be randomized to apply 30% mannitol in vehicle cream and 10 to apply vehicle cream alone for one week during which daily pain levels and use of medication and alcohol will be measured together with the mode of application (rubbing in or applying it to cling wrap then applying the cream coated cling wrap to the skin in cases of severe allodynia). After a three day washout period, they will be given the cream they did not receive previously for one week. The same variables will be recorded daily. The data collected in the first 24 days will be used to generate a power analysis. Following this, all subjects will receive the 30% mannitol cream to apply for three months. Their pain levels, medication intake and method of application will be measured once a month for three months. T-tests will compare the pain levels for mannitol and placebo users before and after one week of the use of each cream to see if the mannitol cream provides better short term pain relief than placebo. Repeated measures ANOVA (Analysis Of VAriance) will compare pain levels before using the mannitol cream and monthly for three months to assess the long-term effects of mannitol cream. Variables collected at each visit, which will not be used for statistical purposes in the current very small pilot project but may be used in a later study, include: application method, effect and side effects of the cream, medication and alcohol use, PHQ - 9 (Personal Health Questionnaire, 9 questions), and questions from the brief pain inventory score. At three months, a satisfaction score will be added to the database. If pain persists beyond 3 months, participants will be offered mannitol and menthol cream for one month, following which their pain levels, PHQ - 9 and brief pain inventory scores will be checked.

Eligibility criteria: Inclusion Criteria

1. - Suffering from post-herpetic neuralgia on the trunk or the extremities for at least three months.
2. - Maximum daily pain score greater than or equal to 5/10.
3. - Having failed to improve with at least one neuropathic pain medication.

4- Able and willing to fill a fluid survey NRS pain scale and a medication intake questionnaire daily, preferably online but on paper, if unable, for the first 24 days of the study, then once a month for three months..

5 - Preferably have access to someone who can apply cream to their back if they have pain in the back and cannot reach the area.

6 - If that is not possible, ability to apply the cream to their own back, using an applicator which will be supplied.

Exclusion Criteria:

1. Allergies to any of the ingredients of the cream
2. Open lesions or abrasions on the skin where the cream will be applied
3. Using corticosteroids
4. Unwilling to stop using other topical products (creams or patches) for the treatment of post-herpetic neuralgia
5. Pregnant, breast-feeding or not using birth control
6. Suffering from severe chronic pain from a cause other than post-herpetic neuralgia

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Primary outcomes:
measure: Change in worst NRS (Numerical Rating Scale) pain score
timeFrame: Before each cream is first applied, 7 days later, and for mannitol cream 1,2 and 3 months
measure: Change in average NRS (Numerical Rating Scale) pain score
timeFrame: Before each cream is first applied, 7 days later, and for mannitol cream 1,2 and 3 months
Secondary outcomes:
measure: Change in Pain medication intake
timeFrame: Before each cream is first applied, 7 days later, and for mannitol cream 1,2 and 3,months
measure: Change in Alcohol intake
timeFrame: Before each cream is first applied, 7 days later, and for mannitol cream 1,2 and 3 months
measure: Change in questions from the brief pain inventory score
timeFrame: Before each cream is first applied, 7 days later, and for mannitol cream 1,2 and 3 months
measure: Change in PHQ-9 (Personal health questionnaire, 9 questions) Score
timeFrame: Before each cream is first applied, 7 days later, and for mannitol cream 1,2 and 3 months
measure: Change in Method of cream application
timeFrame: when each cream is first applied, 7 days later, and for mannitol cream 1,2 and 3 months
measure: Change in effect and side effects of the cream
timeFrame: Daily for the 14 days, of the crossover study, then at 1,2 and 3 months
measure: Satisfaction from cream use
timeFrame: Three months after use of mannitol cream was started.
measure: Change in pain score from mannitol cream use to mannitol and menthol cream use
timeFrame: 1st measurement Three months after use of mannitol cream was started 2nd measurement one month after mannitol and menthol cream started
Other outcomes:
Locations:
city: North Vancouver
country: Canada
facility: Dr. Helene Bertrand Inc.
state: British Columbia
Study officials:
affiliation: University of British Columbia, Department of family practice
name: Helene Bertrand, MD, CM, CCFP
role: PRINCIPAL_INVESTIGATOR
References:
citation: Bertrand H, Kyriazis M, Reeves KD, Lyftogt J, Rabago D. Topical Mannitol Reduces Capsaicin-Induced Pain: Results of a Pilot-Level, Double-Blind, Randomized Controlled Trial. PM R. 2015 Nov;7(11):1111-1117. doi: 10.1016/j.pmrj.2015.05.002. Epub 2015 May 12.
citation: Gilron I, Baron R, Jensen T. Neuropathic pain: principles of diagnosis and treatment. Mayo Clin Proc. 2015 Apr;90(4):532-45. doi: 10.1016/j.mayocp.2015.01.018.
citation: Shannon HJ, Anderson J, Damle JS. Evidence for interventional procedures as an adjunct therapy in the treatment of shingles pain. Adv Skin Wound Care. 2012 Jun;25(6):276-84; quiz 285-6. doi: 10.1097/01.ASW.0000415345.22307.f3.
citation: Szolcsanyi J, Sandor Z. Multisteric TRPV1 nocisensor: a target for analgesics. Trends Pharmacol Sci. 2012 Dec;33(12):646-55. doi: 10.1016/j.tips.2012.09.002. Epub 2012 Oct 12.