Efficacy and Safety of Topical Versus Systemic Treatment in Postherpetic Neuralgia and Diabetic Polyneuropathic Pain

The purpose of this study is to evaluate lidocaine as topical treatment for peripheral neuropathic pain (as stand-alone treatment and in combination with systemic treatment)


Eligibility Criteria:
Inclusion Criteria:

* Male or female subjects with \>= 18 years of age
* Intact skin in the area of topical treatment
* Creatinine clearance CLCR \>= 30 mL/min
* NRS-3 \> 4 (recalled average pain intensity during the last 3 days)

Subjects with DPN

* Controlled, treated type 1 or 2 diabetes mellitus with glycosylated hemoglobin (Hba1c)\<= 11%
* Painful, distal symmetrical, sensomotor polyneuropathy of the lower extremities for \>= 3 months (below the knees on both extremities) with at least 2 of the following symptoms present: burning, sensation, tingling or prickling, numbness from time to time, painful heat or cold sensation (e.g. warm or cold water)

Subjects with PHN

* Subjects with PHN and neuropathic pain present for \>= 3 months after healing of the herpes zoster skin rash.
* Without neurolytic neurosurgical therapy for their condition.

Exclusion Criteria:

General

* Evidence or history of alcohol, medication or drug abuse and/or dependency in the past 2 years, unstable psychological personality requiring intermittent or permanent treatment.
* Psychiatric illness (subjects with well-controlled depression or anxiety disorder may participate if they are not taking any of the prohibited medications defined (below), epilepsy or suicide risk.
* Pregnant or breastfeeding women
* Women of childbearing potential who are sexually active without satisfactory contraception for at least 28 days prior to enrollment, during the trial, and until 28 days after the follow-up visit.
* Subjects with severe cardiac impairment e.g. NYHA class \> 3, myocardial infarction less than 6 months prior to enrollment, and/or unstable angina pectoris.
* Subjects with severe hepatic disorder and/or AST or ALT \>= 3x the upper limit of normal.
* Subjects with known or suspected severe renal failure (CLCR \< 30 mL/min).
* Anticipated need for surgery during the trial, requiring at least regional or general anesthesia.
* Subjects who are undergoing active treatment for cancer, are known to be infected with HIV or being acutely and intensively immunosuppressed following transplantation.
* Participation in another trial of investigational medicinal products or devices parallel to or less than 1 month before entry into the trial, or previous participation in this trial.

Trial specific:

* Any concomitant use of drugs for the treatment of neuropathic pain or commonly used for the treatment of neuropathic pain.
* Use of transcutaneous electrical nerve stimulations (TENS) after enrollment.
* CLCR \< 30 mL/min
* Evidence of another cause for pain in the area of neuropathic pain such as lumbar radiculopathy, surgery trauma, restless legs syndrome, if this coud confound the assessment or self-evaluation of the neuropathic pain.
* Presence of other severe pain that could confound the assessment or self-evaluation of the neuropathic pain.
* History of malignancy within the past 5 years (with the exception of basal cell carcinoma).

Subjects with PHN

* Active herpes zoster lesion or dermatitis of any origin at the affected site with PHN.
* Subjects who had neurological ablation by block or neurosurgical intervention for control of pain in PHN.

Subjects with DPN

* No palpable pulse of the arteria dorsalis pedis in both feet.
* Clinical signs for venous insufficiency and/or postthrombotic syndrome Sage III/IV (i.e. extensive varicoses)
* Ulcers on the lower extremities.