Chronic pain & opiates (part 1)

Pain, pain go away…..if only it were so easy.  A new facebook friend is suffering terribly at the moment, whilst trying to do what the hospital requires for a spinal cord stimulator trial.  Trying to offer some words of advice and encouragement has got me thinking and I thought I’d have a stab at talking about opiate use in chronic pain.

I don’t know what the policies of other pain centres are, but the consultants at St Thomas’ recognise that opiate substances – control drugs such as morphine, pethidine & oxycodone – are not necessarily the right fit for every type of pain.  The majority of what I am going to write is from personal experience – both in my other life as a palliative care nurse, and from now living with chronic pain.  I’ll try not to become too medical and I may spread this over several posts as I really don’t want to bore you!  I have done a little medical reading to ensure that I am giving you the latest thinking and for those with medical minds I will list some of the articles that I’ve read – although I wouldn’t necessarily recommend them, bedtime reading they ain’t!!

In cancer care and particularly palliative care, opiates have long been the gold standard for pain relief.  Diamorphine, pure “medical” heroin, was the drug of choice when I started working in cancer care, but even then nerve or neuropathic pain was a nightmare for us to control.  Try to visualise your nervous system as a circuit board whose main branch is the spinal cord, which is supplied with its impulses to & from a source that is your brain. The channels of the circuit are made up of building blocks, cells called neurons, which transmit the messages to & from the brain. The unknown quantity is: in the circuit that processes and transmits pain, which neurons are those providing the output that drives the pain network within the brain where chronic pain is present.  Still with me?  In chronic pain the firing activity of the neurons is changed, but it is still unknown quite how it is altered.

images (19)

I have sat in some very complicated pain management sessions in my time when the descriptions of the different pain receptors almost went over my head.  All you need to know is that the building blocks contain different receptors which convey different sensations and so respond to different drugs.  Think of a lock and a key – a particular key (the drug) is needed to open a lock (the pain receptor).  When opiate drugs are used for pain control, the receptor that responds to morphine etc is Mu, but there is now known to be an optimum time period for use of these drugs – probably about 3 months.  After a while the opiates cause the down regulation of the Mu receptors, which means that fewer receptors need more opiate molecules to get the same feeling of relief.  Eventually the loss of these receptors means that our bodies cannot regulate the feeling of pain so well – and produces what the medics call “hyperalgesia”.  When your consultant tells you that the opiates may be increasing your pain rather than reducing it, this is what he is talking about!

But where does this leave me, the person with the chronic pain? To be continued….

neuron_cartoon

 

 

“Personalised Medicine & Opiod Analgesic Prescribing for Chronic Pain: Opportunities and challenges”  Stephen Bruehl et al, The Journal of Pain, Feb 2013, Vol 14

“Increased Pain Sensitivityin Chronic Pain Subjects on Opioid therapy….” Yi Zhang et al, American Academy of Pain Medicine, 2015, Oxford University Press

“Narcotic Drugs for treatment of Chronic Pain: a double edged sword” Peter Ullrich, Spine-health.com, 2012

“How Pain killers sometimes increase Chronic Pain” Stepahnie Burke, Spine-health.com, 2013

Think this is enough……I apologise if this is too medical, the next part won’t be!

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s