Pain is an essential sensation which has protected human beings an other living creatures for many centuries. People who have a reduced ability to feel pain are susceptible to damage to their bodies (e.g. diabetics). Despite pain being useful, it is of course extremely unpleasant. These pages explain some of the common causes of pain, what makes it worse and what makes it better. They explain the different types of pain killers and why they are given in different situations, which pain killers can be taken together and which combinations have to be avoided. The side effects of painkillers are explained together with advice on how to alleviate them.
Patients and carers with a better understanding of their pain killers are more likely to take them properly, have most benefit and have less side effects.
|Types of pain||Guidelines for pain management|
|Analgesics for mild and moderate pain||Analgesics for severe pain|
|Morphine preparations||Side effects of Morphine|
|Other strong pain killers||Use of syringe drivers|
|Other drugs for bone pain||Other drugs for nerve pain|
Types of cancer related pain
Tumour are generally not painful on their own. They cause pain by pressing on or damaging adjacent organs so the types of pain depends mainly on which organ or structure is being damaged. The description of pain one individuals description of pain in terms of character and severity varies enormously:-
Bone pain - A background constant pain (like tooth ache) made worse by moving or putting weight on the effected bone. In the legs, spine or hips this would be standing or walking for ribs this may be sneezing, coughing, taking a deep breath or lying on one side. Disease in the bone can increase the risk of fraction - the pain here would be more severe and often combined with swelling, bruising and disability.
Liver pain - In the right upper side of the tummy (abdomen) can extend under the ribs and across the front of the stomach area (upper central part of the abdomen). Can be associated with a pain in the right shoulder (this is called referred pain and does usually mean there's anything wrong with the shoulder). There is generally a dull ache associated with mild nausea but usually made worse in different positions or taking deep breaths, coughing or sneezing. It may be associate dwith signs of liver disease (see jaundice).
The lining of the lung - This is called the pleura and hence it is also called pleuritic pain. In the same way as rib pain this is made worse by walking for ribs this may be breathing, sneezing, coughing, taking a deep breath.
Nerve pain (neuropathic pain, neuralgia). Caused by pressure on or damage to nerves. Often associated with altered sensation or weakness. At first there may be increased sensation in the area of skin the nerve supplies. This is called hyperaesthesia and patient describe it as a burning sensation. As the nerve damage becomes more severe numbness develops. The pain is sharp and often "shooting down the affected limb". Sciatica for example is caused by pressure on the nerve roots which come from the lower pain. Many of us have experience this from time to time, the pain tends to shoot down the back of the legs.
There are several causes of headaches:-
Indigestion is the feeling of discomfort or pain within the lower chest of abdomen (Tummy) caused by an abnormality or disjunction of the gut or bowel. There are several other causes of pain within the abdomen from other organs such as the pancreas, lymph nodes, liver, kidney, spleen or aorta but this page only deals with those caused by the gut itself.
The following list summarises some of the causes and advice on some other medications used to alleviate the symptoms. The types of indigestion can be split into four main categories depending on which part of the gut is affected:-
Heart burn - A burning feeling in the center of the chest, sometimes combined with an acid taste in the back of the mouth. Usually may worse by eating a large meal, straining or leaning forward. This is a long standing problem in many people caused by acid from the stomach refluxing back into the gullet. The steroids which are given with chemotherapy often make this symptom worse or even bring it on in patients who have not previously experienced it. Often medication is prescribed to prevent this symptom - click on the headings in the adjacent column. There are also several practical manoeuvres which can be performed. These include; Eating small meals often - see diet & indigestion. Putting two bricks under the head of the bed. Avoiding tight clothing around the abdomen.
If there is vomiting several hours
after food and the food is clearly not digested this may be due to an obstruction of the
stomach - gastric outlet obstruction. You doctor should be aware of this.
Associated with diarrhoea. This is
often associated with a discomfort in the lower abdomen. If severe it may be associated
with colicky pains described above.
A number of drugs are available for diarrhoea including Codeine and loperamide although a change in diet may help - see diet & diarrhoea
A feeling of fullness in the back passage. May be associated with a blood on the stool or a mucous discharge form the back passage. Often caused by radiotherapy to the lower pelvis can be help with suppositories such as xyloproct or scheriproct - ask your doctor.
Analgesia for chronic pain
Analgesics for chronic pain should always be prescribed regularly, not just when required. It is important to take the correct painkillers for your specific type and level of pain. The World Health Organisation issued guidelines describing 3 steps in analgesic prescribing, the "analgesic ladder":-
Freedom from pain
|Pain persisting or increasing - step up||Step 3: Strong Morphine drugs +/- co-analgesia*|
|Pain persisting or increasing - step up||Step 2: Weak morphine like drugs +/- co-analgesic*|
|Pain persisting or increasing - step up||Step:1b Non morphine drugs +/- co-analgesia*|
|Pain||Step:1a Over the counter or non-prescription drugs|
*A co-analgesic is a drug (or device) which may or may not have intrinsic analgesic activity, but which when used with conventional analgesics may contribute significantly to pain relief. If pain is difficult to control always review the addition of co-analgesics
Patients should start on step 1,2, or 3 depending on the severity of their pain
Where pain is persisting or increasing, despite the use of co-analgesics, a patient's analgesics should be changed to those on a higher step on the ladder: where pain is improving analgesics should be reduced and/or changed to those on a lower step on the ladder.
A) Step 1a - non prescription (over the counter pain killers)
Despite the wide range of over the counter products available the active painkiller ingredients are one of the 4 following drugs used alone, in combination with each other or with other drugs:-
Step 1b - Non morphine drugs +/- co-analgesia*
Paracetamol 1g qds, Aspirin 600 - 900 mg qds
Volterol 50 mg qds (or another suitable non-steroidal analgesic - see NSAI section)
B) Step 2 - weak morphine-like drugs
These may used in combination formulations with non-opioids for patient convenience eg:-
Coproxamol (paracetamol 325 mg + dextropropoxyphene 32.5 mg) - 2 tablets qds
Tylex / Solpadol (paracetamol 500 mg + codeine 30 mg) - 2 tablets qds
Alternatively prescribe two drugs separately
Dihydrocdeine 30 - 60 mg qds + Paracetamol 1g qds
The use of the following drugs is to be discouraged as they contain sub-therapeutic doses of weak opioids:
codydramol ( paracetamol 500 mg + dihyrocodeine 10 mg)
cocodamol (paracetamol 500 mg + codeine 8 mg)
C) Step 3 - Analgesics for severe pain: morphine preparations and dose titration (STRONG OPIOIDS)
Before prescribing strong opioid analgesics, always ascertain whether the patient would achieve adequate symptom control on a weak opioid +1- a coanalgesic
Commonly used drugs are:
Oral morphine is the drug of choice in the majority of patients with severe pain. Oral morphine preparations
a) Immediate release (Prescribe regularlv 4 hourly)
b) Controlled release
Tips to start morphine and convert and titrate immediate release to controlled release morphine:-
Converting to MST from oral morphine or its equivalents.
Oral morphine - To convert to MST, once the pain is adequately controlled on 4 hourly immediate release preparations. Add up the total morphine requirement in the previous 24 hours and divide by 2 to get the morning and evening MST doses ie. exactly 12 hours apart. For breakthrough pain, always prescribe immediate release morphine at the equivalent 4 hourly dose. For intravenous morphine divide by 4 to to get the morning and evening MST doses.
|Diamorphine oral||x1 - 1.5|
4. Side effect: and toxicity of morphine
a) Important side effects
Codanthramer capsules* 1-4 bd
Codanthramer suspension* 10-40 mls bd
Codanthramer strong capsules* 1-4 bd
Docusate 100 - 200 mg tds
Bisacodyl 5 - 10 mg bd
Milpar 10 - 20 mls bd
Senna 2 - 4 tabs bd
* Avoid danthron, containing aperients (codanthramer) in patients who are incontinent or who have an indwelling catheter, because of the risk of danthron burns
Titrate the laxative dose as required for the individual patient.
Prescribe prophylactic antiemetic e.g. Haloperidol 1.5 mg nocte
Domperidone 10 - 20 mg tds
Metochlopramide 10 - 20 mg qds
Warn patient and reassure
5. Opiold prescribing in renal impairment
Morphine is metabolised to morphine-3-glucurnnide (M-3-G) and morphine-6-glucuronide (M-6-G). While M-6-G has traditionally been regarded as the active metabolite of morphine, current research has shown that M-3-G may also have some activity. Both metabolites are renally excreted, and accumulate in renal impairment, causing toxicity
When prescribing opioid analgesics in patients with renal impairment, great care must he taken as these patients are extremely sensitive to oploids
Suggested management strategies are:
a) Prescribe smaller doses of opioid analgesic. N.B. the dose reduction required will depend on the degree of renal impairment
b) If there are still problems with toxicity, administer small doses of opioid less frequently, i.e. 6-8 hourly.
c) Convert to phenazocine which is metabolised to inactive products in the liver
6. Alternatives to oral morphine for severe pain
Very few patients are truly morphine intolerant
There is no place in the routine management of chronic cancer pain for short acting opiold analgesics such as pethidine and dextromoramide
If the pain is not responding to morphine always consider the aetiology of the pain and review the use of coanalgesics
a) Phenazocine - For patients who have unacceptable drowsiness/nausea on oral morphine preparations, a trial of phenazocine may be indicated.
The starting dose of phenazocine is usually 2.5 mg 6-8 hourly
Breakthrough phenazocine should be prescribed and should be equivalent to the 6-8 hourly regular dose
The dose of phenazocine should be titrated by 2.5 mg increments as guided by the number of breakthrough doses required/day
b) Transdermal Fentanyl - TTS Fentanyl is a new synthetic opioid preparation and may be considered in the following patient groups:
Stable opioid requirements but unacceptable constipation. Mood disturbance nausea & vomiting number of tablets. Unable to swallow. Fentanyl is unsuitable in patients with:
When converting to patches from oral morphine, patients will usually require three 4 hourly doses until the subcutaneous depot has built up. Proximate conversions from oral morphine to transdermal fentanyl are as follows:-
|Total oral morphine (mg/day)||TTS fentanyl (mcg/hr)|
Converting to fentanyl patches from slow release morphine.
e.g. MST 60 mg bd = TTS fentanyl patch 25 mcg/hr the 'breakthrough' dose of sevredol = 20 mg as required
IMPORTANT - A subcutaneous depot of fentanyl persists for up to 24 hours after patch removal. Patients converting from TTS fentanyl back to mophine should not restart regular oral morphine for at least 12 hours after the patch has been removed, but may have it when required - pm.
The first fentanyl patch needs to be applied at the same time as the last dose of MST. Breakthrough Sevredol / Oramorph should be prescribed with TTS fentanyl, at the breakthrough dose that would be needed it the patient was taking the equivalent dose of MST.
7. The use of syringe drivers for subcutaneous infusions
Many drugs are well absorbed subcutaneously, and this route removes the need for intravenous cannulation in terminally ill patients and is particularly useful in those with dysphagia, persistent vomiting, bowel obstruction patients too weak to take oral medication
Diamorphine More soluble in solution, so better absorbed than morphine subcutaneously
Oral morphine (3): Subcutaneous diamorphine (1)
* These drugs must only be mixed with a total volume of at least 48 mls using a 10 or 20 ml syringe. The same principle should apply to the other listed drugs to avoid precipitation. NOTE:-
· Dexamethasone and cyclizine cannot be mixed with octreotide
· Cyclizine can precipitate, especially in maximum dose (150 mg/day), and the syringe driver must be checked regularly.
8. Coanalgesics: Bone pain
Radiotherapy is the treatment of choice for painful bone metastases and should be considered in conjunction with coanalgesics. Further treatment options for bone pain are as follows:
Local anti-inflammatory action (inhibitors of prostaglandin synthesis)
If previous peptic irritation prescribe prophylactic H2 blocker or misoprostol (NB. PR/topical routes do not protect from systemic toxicity)
Diclofenac and Naproxen are the NSAIDs of choice as both have a good toxicity profile, and in particular less GI toxicity than most other NSAIDs
Ketorolac is a potent anti-inflammatory which can be administered subcutanously, and may be beneficial even when other NSAIDs have been ineffective: Always give test dose of 25 mg sc. prior to infusion maximum 24 hour dose = 90 mg by continuous sc. infusion.
h) STEROIDS - Dexamethasone
Anti inflammatory +/- anti-tumour action
Start with high dose but try to reduce to lowest effective dose to avoid toxicity
Always prescribe a H2 blocker or misoproslol if used in conjunction with NSAID.
i) BISPHOSPHONATES - Aredia, bonefos, loron
Potent inhibitors of osteoclast-mediated bone resorption. The most commonly used bisphosphonates are pamidronate and clodronate - click here for details on bone hardening drugs. Assess response after 2-3 doses, and continue in responding patients until no further benefit.
9. Coanalgesics: Neupathic pain
Pain associated wfth dysaesthesia (numbness): start antidepressant
Shooting pains: start anticonvulsant
2nd line: add in anti-arrythmic
Central and peripheral action on serotonin and noradrenalin mediated neurotransmission
Give at night and build up dose gradually to avoid excess sedation. Start with low dose and increase every 3 - 5 days
e.g. Amitriptyline 25 - 150 mg nocte
Dothiepin 25 - 150 mg nocte
b) Anticonvulsants (best prescribed under the supervision of a pain specialist)
Start at low dose and gradually increase to avoid sedation and central toxicity
e.g. Carbamezepine 100 - 400 mg bd/tds
Sodium Valproate 200 - 600 mg bd/tds
c) Anti-arrythmics (best prescribed under the supervision of a pain specialist)
Avoid flecainide if there is a history of ischaemic heart disease ECG should be performed prior to starting treatment
e.g. Flecainide 100-200 mg bd
Mexilitine 200 mg tds
d) Ketamine d) Ketamine (best prescribed under the supervision of a pain specialist)
NMDA receptor antagonist
Useful for difficult neuropathic pain when used in sub-anaesthetic doses, but role still being evaluated
Dose: Ketamine 10 mg (sc.) loading dose
120 - 150 mg/12 hours by sc. infusion
N.B. If effective, the morphine dose may need to be reduced by as much as 75% of previous dose
e) Topical local anaesthetics I NSAIDs
Some reports of therapeutic efficacy, but role not yet fully evaluated
e.g. Lignocaine gel 2% } Applied regularly. or Voltarol gel
Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. Cancernet.co.uk has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.