A Study With Lido-Patch and Placebo Plaster in Patients Suffering From Postherpetic Neuralgia (PHN)

The time to exit was defined as the number of days after randomization where worsening of the pain relief score by 2 or more categories on a 6-item pain relief scale (verbal rating scale, VRS) on 2 consecutive days in comparison to the average pain relief in Week 8 of the Run-in Phase was reported.

The average pain relief in Week 8 of the enrichment phase was to be stated by the participant at the randomization visit. The VRS comprised the categories 1 = worse, 2 = no pain relief, 3 = slight, 4 = moderate, 5 = a lot, 6 = complete.

Pain intensity was assessed as "pain right now" directly before patch application and before patch removal, and as "24-hour average pain" before patch removal using an 11-point Numeric Rating Scale (NRS from 0 = no pain to 10 = pain as bad as you can imagine).

Pain relief was defined as relief at the time point directly before patch removal in comparison to the time point directly before patch application. Pain relief was assessed using a 6-item relief scale (VRS) with categories 1 = worse, 2 = no pain relief, 3 = slight, 4 = moderate, 5 = a lot, and 6 = complete.

The weekly average of the 24-hour average pain intensity was calculated based on corresponding daily pain intensities over the last week before the respective visit. Pain intensities were assessed using an 11-point Numeric Rating Scale (NRS from 0 = no pain to 10 = pain as bad as you can imagine).

The weekly average of the current pain ("pain right now") intensities before patch application or before patch removal were calculated based on corresponding daily pain intensities over the last week before the respective visit. Pain intensities were assessed using an 11-point Numeric Rating Scale (NRS from 0 = no pain to 10 = pain as bad as you can imagine).

The weekly average pain relief was calculated based on daily pain relief over the last week before visit. Pain relief was assessed using a 6-item relief scale (VRS) with categories 1 = worse, 2 = no pain relief, 3 = slight, 4 = moderate, 5 = a lot, and 6 = complete.

Weekly worst pain intensity was assessed in the last week before the visit using an 11-point NRS (from 0 = no pain to 10 = pain as bad as you can imagine).

Weekly average pain intensity was assessed in the last week before the visit using an 11-point NRS (from 0 = no pain to 10 = pain as bad as you can imagine).

Weekly least pain intensity was assessed in the last week before the respective visit using an 11-point NRS (from 0 = no pain to 10 = pain as bad as you can imagine).

The CPSI is a 5-point verbal rating scale (VRS) designed to provide information on the influence of the pain on sleep quality with the items trouble falling asleep, needing sleep medication, and awakened by pain during the night/in the morning (categories of the VRS: never, rarely, sometimes, usually, always); in addition, the overall quality of sleep (categories of the VRS: poor, fair, good, very good, and excellent) was assessed. Participants were asked to complete the CPSI questionnaire at each visit.

The SF-MPQ includes 15 words (11 sensory, 4 affective). Each word or phrase is rated on a 4-point intensity scale (0 = none, 1 = mild, 2 = moderate, and 3 = severe). In addition, the 6-point Present Pain Intensity (PPI) rating (no pain, mild, discomforting, distressing, horrible, excruciating) is included as a visual analogue scale for rating pain intensity.

Investigators were to describe their global impression of change (CGIC), i.e., the overall impression of the change of the participant's condition by answering the question "Compared to the patient's condition at admission to the project, how much has he/she changed?" The verbal rating scale comprises the categories not assessed [0], very much improved [1], much improved [2], minimally improved [3], no change [4], minimally worse [5], much worse [6], and very much worse [7]. When assessing the overall impression, the investigator was to refer to the Run-in Phase only.

The Short Form 36 Quality of Life Index (SF-36 [Trade Mark]) standard version with a 4-week recall period was used as a self-assessment.

Eleven questions were answered on binomial (Yes/No) or on 3-, 5-, or 6-point categorical scales to generate the 8 raw scales (Physical Functioning, Role-Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role-Emotional, Mental Health). Higher values of the raw scales represent a better outcome. The raw scales were converted into a transformed scale (transformed scale = [(actual raw score - lowest possible raw score) / possible raw score range] x 100).

Allodynia severity was rated using the following categorical scale: 0 = no pain or discomfort to touch; 1 = uncomfortable, but tolerable to touch; 2 = painful; 3 = extremely painful, participant cannot stand touching.

The test was conducted by means of a brush (type N12). The painful PHN area was stroked with the brush and the intensity of allodynic pain was assessed.