Medications for low back pain

Presented by:
Dr Brendan Moore — Pain Medicine Specialist Physician

Event:
GP Education Day - 2015

1. What%Medica+on%for%%
Low%Back%Pain?%
Dr#Brendan#Moore#
Pain#Medicine#Specialist#Physician#
%
Adjunct#Associate#Professor,#University#of#Queensland#
Honorary#Associate#Professor,#University#of#Hong#Kong#

2. RaAonal#use#of#analgesia#in#nocicepAve#pain
1
#
#
First line
1. Non-opioid analgesics
– Paracetamol or NSAID
2. Combination therapy
– Use non-opioids first – paracetamol + NSAID
– COX-2 inhibitors
3. If pain persists or involves neuropathic component
– Adjuvant – TCA or anticonvulsant
– Tramadol, Tapentadol
4. Strong opioids
2.##

3. “SciaAca”:#mixed#pain#state#with#several#possible#
pathological#mechanisms#
Baron#R,#Binder#A.#Orthopade#2004;#33:#568S75.###
Central#sensiAsaAon#
Disc#
C#fibre#
C#fibre#
A#fibre#
NocicepAve#component:#
SprouAng#from#CSfibres#into#the#disc#
Neuropathic#component#I:#
Damage#to#a#branch#of#the#C##
fibre#due#to#compression#and#
inflammatory#mediators#
Neuropathic#component#II:##
Compression#of#nerve#root#
Neuropathic#component#III:##
Damage#to#nerve#root#by##
inflammatory#mediators#

4. Analgesic#targets
1
#
#
Pharmacotherapy%
• NonSopioid#
analgesics#
• Adjuvant#analgesics#
• Opioid#analgesics#

7. slide16askin(1).wmv#

8. First#line#treatment#in#nocicepAve#pain:##
NonSopioid#analgesics##
#
#
#
Paracetamol#
NSAIDs#
#
#

9. • Drug#of#choice#in#mild#to#moderate#pain#
• EffecAve#analgesic#and#anApyreAc
#
Benefits%
.#Familiar#
.#High#efficacy#profile#for#mild#nocicepAve#
pain#
.#Minimal#side#effects#
.#Can#be#used#as#adjunct#therapy#with#
NSAIDs#and#op#
First line analgesia – paracetamol

10. • Give#adequate#doses#
• 4#gm#per#day#in#divided#doses#
• Controlled#release#preparaAons#
may#improve#compliance#
• 665#mg#X#2#three#Ames#a#day#
• Paracetamol#when#combined#with#
an#NSAID#allows#a#lower#dose#of#
the#NSAID#
#
Paracetamol – dosing

11. Reactions involved in paracetamol metabolism
3
Non-steroidal anti-inflammatory drugs
(NSAIDs) – biochemical pathway

12. • Analgesic#and#anASinflammatory#
• AnApyreAc#acAon#
• NonSselecAve#cycloSoxygenase#
inhibiAon#of#COXS1##
and#COXS2#
• Inhibit#prostaglandin#synthesis#in#
peripheral#Assues,##
nerves#and#the#CNS#
NSAIDs#

13. NSAIDs#are#valuable#analgesics#inappropriately#
selected#paAents#
#
Consider#whether#the#potenAal#benefits#of#
adding#an#NSAID#outweigh#the#potenAal#harms#
#
NSAIDs (continued)

14. Prefer#NSAIDs#with#a#low#risk#of#gastrointesAnal#
adverse#effects#
##
Assess#cardiovascular#and#renal#risk#before#
prescribing#an#NSAID#
#
Monitor#for#renal#impairment#and#symptoms#of#
heart#failure#in#paAents#at#risk#
#
Use#NSAIDs#at#the#lowest#effecAve#dose#for#the#
shortest#possible#duraAon#
#
NSAIDs (continued)
NSAIDs (continued)

15. Pooled relative risk of serious upper GI
complications with NSAIDs versus ibuprofen

16. Cardiovascular#risk
#
–#Increased#BP#
–#High#cholesterol#
–#LVH#
Diabetes#
Renal#impairment#
MedicaAons#
–#ACE#inhibitors#especially#with#a#
diureAc#
Cardiovascular risk assessment
References: 1. National Prescribing Service, 2008. 2. The Australian COX-2 Specific
Inhibitor Prescribing Group, 2002.

17. • Volume#depleAon#
• MedicaAons##
• –#DiureAcs#
• –#ACE#inhibitors#
• GFR#<60#mL/min#
Renal impairment

18. • PreSexisAng#renal#impairment#
• Hypovolaemia,#hypotension#
• Serious#cardiovascular#complicaAons#have#
been#reported#with#the#use#of#COXS2#
• InteracAons#with#nephrotoxic#agents#and#
ACE#inhibitors#
COX-2 inhibitors – contraindications

19. Second#line#treatments##
in#nocicepAve#pain#
#
CombinaAon#therapy:#
Tramadol,#Tapentadol#
Tricyclic#anAdepressants#
#
#

20. Second%line%treatment:#
• CombinaAon#therapy#improves#efficacy#of#paracetamol#and#
NSAIDs#vs#paracetamol#alone
1,2
#
Many%pa+ents%will%self>prescribe%codeine%as%a%second%line%
treatment
3
%
• Seen#as#a#‘stronger’#analgesic,#paAents#may#not#fully#
understand#the#risk#of#dependence#and#side#effects##
• It#is#important#to#advise#paAents#against#ongoing#use#for#
chronic#pain#
• Consider#TCAs,#tapentadol#or#tramadol#if#mixed#nocicepAve/#
neuropathic#pain#is#suspected#or#if#sleep#disturbance#is#prominent#
Second line treatments

21. Neuropathic#pain#analgesic#
pathways#
#

22. 2
nd
line treatment
2
3
rd
line treatment
2

Neuropathic pain treatment pathways
Multidimensional approach
Coordinated assessment and treatment
GP + psychologist + physiotherapist
Early intervention, diagnosis and treatment result in improved
patient outcomes
1
References: 1. Nicholas, 2004. 2. Allen, 2005.
1
st
line treatment
Tricyclic
antidepressants
or
Antiepileptic
(1 drug only)
2
nd
line treatment
2
3
rd
line treatment
2

Tricyclic
antidepressants
+
Antiepileptic
(combination)
Strong opioids. Alone or
in combination with
tricyclic antidepressants
+/-
Antiepileptic
+/-
Invasive procedures
Dorsal column stimulator

23. First%line%treatment%
%(ini+al%monotherapy%trial)%
%
Tricyclic#anAdepressant##
%%OR###
AnAepilepAc#
First line analgesia – neuropathic pain
1

24. Tricyclic%an+depressants%(TCAs)
#
• EffecAve#therapy#for#neuropathic#
pain
1#
• Amitriptyline#–#iniAal#low#dose#5–
10#mg#nocte
2
#
• Side#effects:#sedaAon#and#
anAcholinergic#effects
2
%
First line analgesia – neuropathic pain
1

25. Selec+ve%Noradrenalin%Reuptake%Inhibitors%(SNRIs)%
%
Venlafaxine#–#Level#II#evidence,#inhibits#the#reuptake#
of#both#serotonin#and#noradrenaline#
DuloxeAne
#
#
Side#effects#include#(but#are#not#limited#to)#agitaAon,#
insomnia#or#somnolence,#gastrointesAnal#distress#and#
inhibiAon#of#sexual#funcAoning#
#
#
#
Second line treatments
Adjuvant therapy in neuropathic pain

26. Gabapen+noids##
#
Have#become#the#treatment#of#choice
1#
#
EffecAve#treatment#for:#
–##Painful#diabeAc#neuropathy,#postherpeAc##neuralgia,#spinal#
#cord#injury#pain#and#HIVS#related#neuropathy##
PharmacokeneAc#advantages


#
#
Anticonvulsants in chronic pain
References: 1. Backonja, 2002. 2. Gilron & Flatters, 2006.

27. Modulates#neurotransmimer#release#e.g.#
Pregabalin#binding#to#alpha
2
Sdelta#
Voltage%gated%
Ca
2+
channel%
NeurotransmiQer%%
tTransporter%
Noradrenaline#
Glutamate#
Substance#P#
Presynap+c%
α
2
δ%subunit%
Postsynap+c%
NeurotransmiQer%binding%site%

28. ##
Pregabalin#binds#to#the#α2δ#subunit#of##
voltageSgated#Ca
2+
#channels#in#the#brain#

29. Benzodiazepines
1
%
#Clonazepam#(0.5–1#mg#bd)#has#been#successfully#used#to#treat#
#phantom#limb#pain#
#Side#effects#include#(but#are#not#limited#to)#dizziness,#sedaAon,#
#depression#
#Tolerance#and#dependence##
Alpha
2
%agonists
2#
#Clonidine#produces#analgesia#at#the#spinal#level#through#
#sAmulaAon#of#cholinergic#interneurons#
#Side#effects#include#sedaAon#and#hypotension#
#
Other adjuvant therapies for neuropathic pain

30. Tramadol#
#
Tapentadol#

32. Opioid prescribing:
dose limits and
considerations%

33. Suggested maximum opioid dose
• Consult a Pain Medicine Specialist if higher doses
considered necessary
1. Hunter Integrated Pain Service. Opioid use in persistent pain. November 2010
Drug Maximum dose for GP
prescription
Morphine 120mg daily
Oxycodone 80mg daily
Hydromorphone 24 mg daily
Methadone 40mg daily
Fentanyl transdermal patch 25 mcg/hr applied every 3

days
Buprenorphine transdermal patch 40 mcg/hr applied weekly
Tramadol 400 mg daily

34. Dose conversion
Morphine
equivalence to
Ratio
morphine
: named
opioid
Examples of equivalent doses
Codeine 1:6 Morphine 10 mg Codeine 60 mg
Oxycodone 1.5:1 Morphine 60 mg Oxycodone 40 mg
Hydromorphone 5:1 Morphine 60 mg Hydromorphone 12 mg
Tramadol 1:5 Morphine 10 mg Tramadol 50 mg
Fentanyl Morphine 90 mg Fentanyl 25 mcg/h
Buprenorphine 75:1 Morphine 9 mg Buprenorphine 5 mcg/h
Methadone 3:1 Morphine 60 mg Methadone 20 mg
1. Hunter Integrated Pain Service. Opioid use in persistent pain. November 2010

35. Opioid trial guidelines
• Commence trial with low dose sustained-release
opioid

Use a lower dose and titrate slowly in patients
who are:

• Elderly
• Taking other CNS depressants
• Opioid naïve
• Have severe hepatic or renal dysfunction


1.  Graziotti & Goucke, 1997.

36. Review of opioid trial
• Discuss progress and outcomes
• Functional goals achieved?
• Medication used responsibly?

• Discuss risks / benefits of continued therapy

• Assess 4 ‘A’s
1

– Analgesia
– Activity
– Adverse effects
– Aberrant drug behaviours
1. Gourlay & Heit, 2005.

37. Federal requirements
PBS prescription
Restricted benefit
• Chronic severe disabling pain not responding to non-
narcotic analgesics (treatment <12 months)
• If treatment required beyond 12 months, patient must be
reviewed by a second medical practitioner
• Authority required when prescribing increased quantities
of opioid and/or repeats
– By phone – 1 month’s supply with no repeats
– In writing – 1 month’s supply with 2 repeats
• Short term supply can be prescribed without an authority
Department of Health and Ageing, 2008.

38. State requirements - QLD
• If intend to prescribe S8 drugs for longer than 8 weeks,
forward a “Report to the Chief Executive” through the
Drugs of Dependence Unit (DDU)
• A treatment approval from the Chief Executive is required
prior to treating, for any controlled drug for a patient
considered to be drug dependent
• For approvals and “Reports to the Chief Executive” contact
the Drugs of Dependence Unit
– Phone [phone]
– Fax [phone]

39. Preventing doctor-shopping
Medicare Australia
Prescription Shopping Information Service
• If patient suspected of getting medicine in excess
of medical need, contact the Prescription
Shopping Information Service:
– Complete and sign the registration form available at
www.medicareaustralia.gov.au
• Registration confirmed within 2 business days (fax) or by
mail
– Information Service available 24/7 for registered GPs to:
• Find out if patient has been identified under the
Prescription Shopping Program
• Receive information on the amount and type of PBS
medicine recently supplied to that patient
!%1800%631%181%%