1. Neuropathic pain and Qutenza
Dr Stephen Humble
Consultant in Pain Management & Anaesthesia
Charing Cross Hospital
Dorset Naga
~1,000,000 SHU

2. IASP Definition:
An unpleasant sensory and emotional experience associated with actual or
potential tissue damage, or described in terms of such damage.
Pain is always subjective.
What is Pain?

3. Rene Descartes
Pathology → nerve ending → neural impulse → brain → pain
Pain has underlying pathological cause
If no cause found: ‘malingering or crazy’
How do we feel pain?

4. Nociceptive stimulation of A Delta & C nerve fibres (e.g. by
inflammation)
1st
order neuron to spinal cord
2nd
order neuron via spinothalamic tract
3rd
order neuron from thalamus to cortex
Rx: Paracetamol, NSAIDs, Opioids
Nociceptive Pain Pathway

5. Pain as an evolutionary defence

6. Phantom limb pain
Complex Regional Pain Syndrome
Post Herpetic Neuralgia
Central Post Stroke Pain
Chronic scar hypersensitivity
How can these be an evolutionary defence?
But what about Neuropathic pain?

7. Pain in an area of neurological dysfunction
Sharp, burning, electric shocks, squeezing
Poor response to usual analgesics
Can last after area has healed completely
Neuropathic pain

8. Conditions:
PHN, Chronic post surgical pain, diabetes, HIV, chemotherapy
Prevalence:
>1%
Features:
Hyperalgesia - an increased response to a painful stimulus
Allodynia - pain due to a non-noxious stimulus
Prognosis:
No known cure
Often minimally response to analgesic medication
Peripheral neuropathic pain

9. Antidepressants (Amitriptyline, Nortiptyline, Duloxetine)
Anticonvulsants: (Gabapentin, Pregabalin)
Opioid trial (Tramadol, Buprenorphine, Methadone, Morphine)
Hybrid: (Tapentadol)
Topical: (5% Lidocaine, Capsaicin cream, Qutenza Capsaicin 8% patches)
Pharmacological treatment for neuropathic Pain

10. What are Qutenza patches?
Naga Viper
~1,300,000 SHU
Dorset Naga
~1,000,000 SHU
Carolina Reaper
~2,000,000 SHU
Jalapeno
~4000 SHU
Bird’s eye
~200,000 SHU
Capsaicin
~16,000,000 SHU
Medicated patches impregnated with 8% Capsaicin
Capsaicin is the compound that give chilli peppers their kick
Applied to skin for a single 60-minute application (in hospital)
Can be repeated after 3-4 months

11. 0.075% Capsaicin cream effective but poor compliance
Excellent compliance with patches & very minimal side effects
Multiple RCTs showing benefit for peripheral NP
Can work in patients where nothing else works
Rule of thirds
Can get long benefit from single treatment i.e. disease modification
Rationale for Capsaicin 8% patches
Carolina Reaper
~2,000,000 SHU

12. Capsaicin binds TRPV1 receptor on nerve endings
Capsaicin previously thought to only desensitise the receptor directly
However, also has direct toxicity to mitochondria
‘Haircut’ or ‘pruning’ mechanism
How do Capsaicin 8% patches work?
Anand & Bley, BJA 2011Anand & Bley, BJA 2011

13. Imperial Clinical pathway
for Qutenza patch
therapy
Must have peripheral NP
i.e. allodynia /hyperalgesia

14. Inclusion criteria Exclusion criteria
Well localised Peripheral neuropathic pain for > 3 months
e.g. PHN, post-surgical pain, scar hypersensitivity, HIV, painful
chemotherapy neuropathy
Pain score > 4/10
Neuropathic character to pain i.e. burning, sharp, shooting, electric
shocks, dysaesthesia
Patient fully aware of procedure including duration of benefit and
potential side effects
Patient is prepared to put up with burning sensation of the patch
Standard medications for neuropathic pain have already been tried at
appropriate dosages & durations
Patient uncertain if they want to go ahead
Area is on face or head
Presence of broken skin (e.g. in diabetic neuropathy)
Genuine allergy to chilli or other ingredient
Area is too large
Uncontrolled hypertension or unstable angina
Uncontrolled severe respiratory disease
Significant mental illness including severe anxiety/phobia of treatment
Acute physical illness e.g. chest infection
Very high opioid tolerance or drug abuse
Patient unable to be supervised by responsible adult after patch applied
Patient does not have the cognitive capacity to look after the area of
exposed skin safely
Numbness is the problem rather than pain
Fibromyalgia/CWPS
Pregnancy & children (no safety data available)

15. Neuropathic pain is
-a dysfunction of the nervous system
-often under-recognised
-difficult to manage
There is a growing number of pharmacological options
Capsaicin 8% patches
-are an alternative option
-can work for long periods in some cases where nothing else works
Summary

16. Thank you!
The Telegraph:
Scottish nine-year-old boy eats the
world's spiciest chilli and posts reaction
on YouTube
“the first few chews were very hot but
just about manageable.
Then, the volcano erupted.”
Carolina Reaper
~2,000,000 Sc