Neuralgia, Postherpetic
Conditions
Keywords
Remifentanil, Hyperalgesia, Zoster, Postherpetic neuralgia
Brief summary
Postherpetic neuralgia (PHN) is often associated with pain and sensory changes and is the leading type of neuropathic pain in modern clinical pain research. It is characterized by a variety of sensory patterns, which may be categorized into irritable nociceptor and impairment of nociceptor. At date, several lines of evidence lead to the assumption, that mechanical hyperalgesia in PHN is based - at least in part - on central nervous processes of sensitization. In animal studies the investigators have discovered a previously unrecognized effect of opioids, the reversal of long-term potentiation (LTP) at C-fibre synapses, i.e. an opioid-induced depotentiation. In principle, synaptic depotentiation may be permanent or transient. In our study the clinically used ultra-short acting MOR agonist remifentanil normalized synaptic strength after wash-out of the drug. At present it is not known whether opioid-induced depotentiation can be used to the benefit of pain patients. The aim is to study the hypothesis, that pain in a group of PHN patients with predominant mechanical hyperalgesia is reversed by intravenous remifentanil at a plasma target concentration of 18ng/ml (corresponding to about 0.75 µg/kg/min) for 60 minutes compared with PHN patients of other sensory types.
Interventions
DRUGRemifentanil
Remifentanil (Ultiva; Glaxo-Smith-Kline; Vienna, Austria) will be applied intravenously during 60 minutes through a dedicated infusion pump (TCI Alaris PK Syringe Pump, Cardinal Health, Baesweiler, Germany), with a Target Controlled Infusion (following the integrated software algorithm by Minto), reaching the initial 18ng/ml plasma concentration in 180 seconds. This corresponds to approx. 0.7 µg kg-1 min-1.
Sponsors
WWTF, Wiener Wissenschafts-, Forschungs- und Technologiefonds
Vienna General Hospital
Medical University of Vienna
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Patients suffering from PHN. * Pain ≥ 4 out of 10 in numeric rating scale (NRS) * Female and male patients above the age of 18 * Ability to understand/write/read german
Exclusion criteria
* Zoster affecting trigeminal-, opticus region * Any somatic pain which is stronger than the neuropathic pain * Severe progressive disease * Acute cardiac decompensation * Known cardiac valve dysfunction * Known pulmonary hypertension * Cardiac conduction disturbance * Active herpetic lesion * Opioid therapy * Asthma bronchial * Chronic obstructive pulmonary disease \>GOLD II * Severe psychiatric condition * Abuse of alcoholic beverages, drug abuse * Negative neuropathic symptoms * Pregnancy or breast feeding * Participation in a clinical trial in the 2 weeks preceding the study * Allergy against any medication used in the study protocol
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Stimulus-response (SR)-function | 7 days |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Area of dynamic allodynia | 7 days | Brush, Q Tip, Cotton Wool |
| NRS | 7 days | Pain according to numeric rating scale (NRS) |
| Mechanical pain threshold | 7 days | Mechanical pain threshold measured with v. Frey Filaments |
| HPPT | 7 days | Heat pain perception threshold (HPPT) with thermal sensory analyzer (TSA) |
| Pinprick | 7 days | Area of secondary hyperalgesia assessed by pinprick |
| Coolness | 7 days | Coolness perception threshold measured with TSA |
| Warmth | 7 days | Warmth perception threshold measured with TSA |
| LDPI | 7 days | Laser Doppler Perfusion Imager (LDPI) measuring superficial perfusion of the dermatome |
| HPTT | 7 days | Heat pain tolerance threshold (HPTT) measured with TSA |
Countries
Austria
Outcome results
None listed