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DRUG INFORMATION
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Sometimes, an escalation of strong opiates leads to benefit for a few weeks followed by a
return of pain to original levels. If this occurs, do not escalate doses further. Consider
alternative groups of analgesia or early referral to the pain clinic.
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Consider a review within 4 weeks of an escalation of the opiate dose, with an expectation
that the dose will be reduced if there is no clear improvement in pain or function.
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If the dose has reached 180mg morphine or equivalent, it is almost never helpful to escalate
the dose further. Consider adding alternative medications and /or referral to the pain clinic.
Codeine and Dihydrocodeine (DHC)
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10% of Caucasians do not metabolise codeine; DHC can be used instead
Adverse effects include constipation, drowsiness, addiction, tolerance
Buprenorphine patch (Butrans)
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Consider use if patient is unable to tolerate side effects of codeine/DHC
Can be useful when pain is stable
Accumulates less than oral preparations in renal failure
Tramadol
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Has mixed opioid/SNRI activity; consider used in mixed/neuropathic pain
Generally not well tolerated in the elderly
Can lower seizure threshold, so should be used with care in epileptics
Oxycodone MR
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Consider if good analgesic effects with morphine but intolerant of side effects
Reduced incidence of hallucinations and nausea compared to morphine
Note that oxycodone is twice the potency of oral morphine. Ie 10mg oxycodone Is
equivalent to 20mg oral morphine. (Opiate equivalence Tool)
Fentanyl (Matrifen) patch
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Do not prescribe for opiate naïve patients
May accumulate less in renal failure and cause less constipation than oral morphine
Amitriptyline
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Titrate up slowly to reduce side effects
Best taken in the evening to reduce “hang over effect” eg 6-8 pm
Usual maintenance dose is 1-=30mg but up to 75mg can be used if benefits outweigh side
effects
Initial side effects often settle, so encouraging patients to persist can be worthwhile
Nortriptyline is less sedating
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Contraindicated in some conditions eg closed angle glaucoma, severe cardiovascular disease,
arrhythmia, prolonged QT, urinary retention
Gabapentin
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Consider slow titration in elderly or those susceptible to side effects
Max dose 900mg tds
Taper and stop if no benefit
Pregabalin
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At present must be prescribed as Lyrica in neuropathic pain
Useful if anxiety co-exists
Use bd preparation (cheaper than tds)
Consider slow titration in elderly or those susceptible to side effects
Taper and stop if no benefit
Duloxetine
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Use first line in diabetic neuropathy
Useful if depression co-exists
Take with food; nausea may settle with continued treatment
C/I: hepatic impairment or severe renal impairment
Do not co-prescribe another antidepressant nor use with amitriptyline>25mg
Response is usually seen in one week and is unlikely if not seen by eight weeks
Taper over 2 weeks if stopping.