Effects of Pregabalin on Mechanical Hyperalgesia

Inclusion Criteria:

Recruitment:

• Age above 18 years;
• Neuropathic pain of at least 4/10 for at least 6 months;
• Mechanical hyperalgesia;
• One of the following diagnoses: peripheral nerve lesion, plexus lesion, radicular lesion, spinal lesion, polyneuropathy, postzosteric neuralgia;
• No nerve block or other interventional treatment for at least 4 weeks;
• Constant medication for at least 4 weeks;
• Signed informed consent;
• WOCBP must have a negative serum or urine pregnancy test (minimum sensitivity 25 IU/L or equivalent units of HCG) within 72 hours prior to the start of study medication;
• Women of childbearing potential (WOCBP) must be using an adequate method of contraception to avoid pregnancy throughout the study and for up to 4 weeks after the study in such a manner that the risk of pregnancy is minimized.

Enrolment open titration:

• All principal inclusion criteria at recruitment
• Relevant mechanical hyperalgesia: SRF affected/control at least 2.0 with a minimal SRF of 0.8.

Enrolment double-blind phase:

• At least 30% reduction in mechanical hyperalgesia (SRF) in the open titration;
• WOCBP must have a negative serum or urine pregnancy test (minimum sensitivity 25 IU/L or equivalent units of HCG) within 72 hours prior to the start of study medication;
• Women of childbearing potential (WOCBP) must be using an adequate method of contraception to avoid pregnancy throughout the study and for up to 4 weeks after the study (see above recruitment).

Exclusion Criteria:

• Anaphylaxis on the active component or any other component of Lyrica or the placebo (Lyrica®: pregabalin, lactose-monohydrate, corn starch, talcum; capsule shells: gelatine, titanium dioxide (E 171), natriumdodecylsulfat, high dispersive siliciumdioxide, purified water; ink: shellac, black iron(II,III)-oxide (E 172), propyleneglycol, kaliumhydroxide; additionally in placebo: microcrystalline cellulose, sucrose octaacetate, magnesium stearate)
• Intake of gabapentin or pregabalin within the last 4 weeks prior to recruitment
• Any surgery within the last two months or any scheduled surgery within the study period (20 weeks);
• Concurrent unstable disease involving any system, e.g. advanced carcinoma, acute myocardial infarction, renal failure, or any other condition that in the opinion of the Investigator would deem the patient unsuitable for the study;
• History of cerebral vascular or other cerebral disease;
• Concurrent chronic or acute pain of other origin (osteoarthritis), which is not treated effectively
• Concurrent severe mental deficit, e.g. psychiatric disorders as defined by DSM IV including schizophrenia, mood disorders, organic brain syndrome, psychotic/delusional disorders, serious psychosis;
• Concurrent serious neurological disease, e.g. dementia, multiple sclerosis, or any other disease that would have impact on the ability of the patient to give their consent for the participation in the study or influences the pain perception;
• Concurrent atrioventricular block second degree or higher
• Concurrent renal failure (CLcr < 30 ml/min)
• Concurrent hereditary galactose-intolerance
• Concurrent lapp-lactase insufficiency
• Concurrent glucose-galactose-malabsorption
• Concurrent sub-optimal stabilized Diabetes Mellitus (Hb1Ac > 12%)
• Clinical apparent overdosage of opioids or psychopharmaca
• Recent history (6 months) or current evidence of alcohol or drug abuse;
• Participation in any other investigational drug or therapy study within the previous 90 days;
• Women who are pregnant or breastfeeding;
• Women with a positive pregnancy test on enrollment or prior to study drug administration;
• Women of childbearing potential who are unwilling or unable to use an acceptable method to avoid pregnancy for the entire study period and for up to 4 weeks after the study. Women practicing abstinence should use a reliable method of contraception (except birth control pills) if they choose to become sexually active during the study.