A randomised, crossover, double blind comparison of the analgesic effect and patient tolerability of nabilone and dihydrocodeine in chronic neuropathic pai

Completed

• Conditions: Mixed neuropathic pain; Signs and Symptoms; Pain

• Registration Number: ISRCTN15330757
• Lead Sponsor: Cambridge Laboratories Ltd (UK)

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Study Start: 2007-09-12
• Last Update Posted: 13 January 2015

Recruitment & Eligibility

• Status: Completed
• Sex: Not specified
• Target Recruitment: 100

Inclusion Criteria

1. Patients entering the study will be recruited following written informed consent from pain clinics at participating centres
2. Patients will be in the age range 18 - 90 years with a diagnosis of neuropathic pain made according to the criteria set out below
3. Patients may be taking stable dose regimens of paracetamol, anticonvulsants, antidepressants, opioids or Non-Steroidal Anti-Inflammatory Srugs (NSAIDs)
4. Patients taking excluded medications (see exclusion criteria below) may enter the study after a two week period without these medications

Diagnosis of neuropathic pain:
The term neuropathic pain is loosely applied to a variety of heterogeneous conditions and strict diagnostic criteria are difficult to apply. However, for the purposes of this study, the diagnosis will be made on the basis of the following:
1. Pain secondary to an identifiable injury or disease process where damage to the central or peripheral nervous system is suspected
2. Pain persisting for more than three months in the absence of any continuing nociceptive stimulus
3. Pain that is documented as responding poorly to either opioid analgesics or NSAIDs
4. Pain associated with at least two of the following signs/symptoms:
4.1. Abnormal sensation on clinical examination, including sensory loss, paraesthesia, dysaesthesia
4.2. Mechanical allodynia (static or dynamic)
4.3. Pain of a burning character
4.4. Pain of a stabbing or lancinating character
4.5. Signs of sympathetic dysfunction (discolouration, abnormal vasomotor activity, skin trophic changes)

Many conditions may present with neuropathic pain. However, in some conditions the
distinction between primary nociceptive and neuropathic pain is extremely difficult. An
important example of this is in mechanical low back pain where radiation of pain into the legs is commonly reported in the absence of identifiable nerve injury. Given this diagnostic difficulty, for the purpose of this study, patients with lumbar radiculopathy will not be recruited to the study.

The Central Post-Stroke Pain Syndrome seems to have features that are significantly different to other types of neuropathic pain. For this reason, patients with this syndrome will not be included in this study.

Exclusion Criteria

Patients may not enter the study if they have a history of any of the following conditions:
1. Epilepsy
2. Liver disease
3. Psychosis
4. Bipolar disorder
5. Substance misuse
6. Renal failure
7. Adverse reactions to either dihydrocodeine or nabilone
8. Pregnant women, lactating women or women of childbearing potential not using effective methods of contraception
9. Patients involved in ongoing legal action against a third party in which financial compensation is being sought for personal injury alleged to be the cause of the presenting condition

Excluded medications:
Patients may not take the following medications during the study:
1. Dihydrocodeine
2. Antipsychotic drugs
3. Benzodiazepine drugs (excepting stable doses of night-time sedatives)
4. Monoamine oxidase inhibitors

Patients taking dihydrocodeine may enter the study after a washout period of two weeks. Analgesia during this time will be provided with co-proxamol. Patients taking cannabinoid preparations of any kind may not be included in the study.

Study & Design

• Study Type: Interventional
• Study Design: Not specified