Controlling cancer pain

When a patient has cancer, its physical effect is only one determinant of his ''total perceived pain'. His perception of pain is profoundly modified by his psychological state, and by spiritual, social, and financial factors. Depression, anxiety, anger, hopelessness, and a fear of impending death can all add to his suffering, and worsen his pain. Taking the edge off his anxiety with chlorpromazine, for example, may greatly reduce his total perceived pain, as may help with other factors, where this is possible.

Although chlorpromazine is a tranquillizer, and is not an analgesic, it may be so effective in altering a patient's ''total perceived pain', that no analgesic is required. In the control of cancer pain chlorpromazine and drugs like it are called ''adjuvants'. If an adjuvant alone fails, start the patient on WHO's three-step ladder in Fig. 33-2. This consists of: (1) A non[nd]opioid (aspirin or paracetamol). (2) A mild opioid (codeine). (3) A strong opioid (morphine). All of them can be used with or without an adjuvant. Strictly speaking, the use of an ''adjuvant alone' is not one of the steps on WHO's ladder, which starts with Step One (a non-opioid, perhaps with an adjuvant). One contributor considers that chlorpromazine alone (''Step Zero') is a valuable initial step, which may be easier to continue at home, especially in a community with a poor understanding of the potentially harmful effects of strong analgesics. Another contributor considers it quite unacceptable.

The effects of opioids and non-opioids are additive, and make a useful combination, in that non-opioids act peripherally, whereas opioids act centrally.

Give a patient his drugs every 4 hours by the clock. Give them in time, before his pain starts again, and don't give them ''as required' (''p.r.n.'). Give them by mouth, where you can, and allow the family to give them. When he needs morphine, don't be afraid to give it[md]almost all pain yields to it. So don't underprescribe or underdose.

Make sure that patients know that pain can be treated. If legislation controlling the availability of opioids makes this difficult, strive to have it changed. The right dose, of the right drug, at the right time, will completely control cancer pain in 90% of cases. Drugs are much less successful in many forms of non malignant pain. Some of these can be relieved surgically, but the methods available are not sufficiently effective and practical to be described here.

Be careful to distinguish: (1) Tolerance, which is a state in which increasing doses are needed to maintain the initial analgesic effect. (2) Physical dependence, which is the onset of acute symptoms and signs, when the drug is discontinued. (3) Psychological dependence, which is the craving that is shown by drug abusers. Tolerance to opioids is common in cancer patients, but is rarely a problem, and physical dependence does occur. Psychological dependence is rare, and is unimportant, because the patient is going to die anyway.

Finally, don't remove the dignity of dying. We have all got to die one day, hopefully surrounded by our sons and daughters, and not by oxygen tents, tubes, cardiac monitors and alarm buzzers, and with tubes in our every orifice.

PAIN CAN BE RELIEVED GIVE DRUGS ''BY THE CLOCK' Fig. 33-2 WHO's THREE-STEP LADDER OF PAIN RELIEF will alleviate the pain of about 90% of cases of terminal cancer. The method described in the text is a modification of this, and starts with a trial of the adjuvant alone. Give a patient the right dose of the right drug at the right time. Give it at regular intervals, and not merely on demand. Adapted from ''Cancer Pain Relief'. WHO, Geneva.

page587TERMINAL CARE ADMISSION. Admit a patient with terminal cancer if he is in much pain, or has open lesions which his relatives cannot care for. Do so with their full understanding as to why you are admitting him. When you have controlled his symptoms, particularly his pain, consider sending him home; most patients want to go home to die. While he is in hospital, make an exception to your usual rules about visiting, and allow one or two relatives to be with him all the time. Ask a priest to visit him, pray with him, and suggest your nurses do the same.

Efficient nursing will help to alleviate his pain[md]regular turning, mouth care, and the care of stinking ulcers. Congratulate your staff when they care for dying patients kindly. Above all, take an interest in terminal care yourself.

PAIN [s7]RELIEF IN TERMINAL CARE PAIN ASSESSMENT. Ask about the location, distribution, quality, and severity of his pain, whether it is continuous or intermittent, and what factors make it worse or better. Pain precipitated by movement is likely to be less easily relieved than persistent pain. Enquire the extent to which it limits his sleep and other activities, and ask him to compare it with other pains (toothache, labour pain etc.). Assess it as mild, moderate, or severe. Evaluate his psychological state (anxiety, depression, suicidal thoughts, etc.), so that you can assess his ''total perceived pain' in terms of its physical, psychological, spiritual, social, and financial components.

THE ANALGESIC LADDER. Give him drugs in the following order, with the aim of progressively: (1) Increasing his hours of pain-free sleep. (2) Relieving his pain when at rest. (3) Relieving his pain during standing or activity.

Titrate the dose of the drug you give against the pain he has, gradually increasing it, until you get the effect you want. Give each dose by the clock, before the effect of the previous one has fallen off, so as to remove the memory and fear of pain.

WHO's three-step ladder in Fig. 33-2 starts by giving a non- opioid and an adjuvant. The regime below modifies this, and starts with chlorpromazine alone (''Step 0' is controversial, see above).

(0) Give him enough chlorpromazine to make him a little sleepy. Start it before he needs it, and give it regularly.

(1) If chlorpromazine is not enough, add a non-opioid (aspirin or paracetamol).

(2) If chlorpromazine and a non-opioid are not enough, add a weak opioid (codeine or dextropropoxyphene).

(3) If chlorpromazine, a non-opioid, and a weak opioid are not enough, replace the weak opioid by a strong one (morphine or pethidine). The indication for morphine is the intensity of his pain, not the brevity of his prognosis.

Alternatively, omit any of these stages if necessary. If a drug ceases to be effective, don't change to an alternative of similar strength. Instead, go to the next step, and prescribe one that is definitely stronger.

When he goes home, he ideally needs the same drugs as in hospital. Give the family plenty of chlorpromazine, and if necessary aspirin or paracetamol. If he needs pethidine, and they are responsible, give them some. Explain the dangers of pethidine, and that it is to be given to nobody else.

ADJUVANTS act centrally, modify a patient's emotional response to pain, and are the safest drugs to use at home. The most useful one, and the cheapest is chlorpromazine. As a general rule, give it routinely, and add other drugs to it. Alternatively, use prochlorperazine or haloperidol.

Chlorpromazine 10 to 25 mg 4 to 6-hourly, often up up to 100 mg, and sometimes up to 200 mg. It has antianxiety, antipsychotic, and antiemetic effects, and is particularly valuable if morphine makes him sick. Its side effects include hypotension, blurred vision, dry mouth, tachycardia, urinary retention, and extrapyramidal effects.

NON-OPIOIDS act peripherally.

Aspirin 250 to 1000 mg every 4 to 6 hours. The maximum daily dose, before side-effects (gastrointestinal disturbance and faecal blood loss) become severe, is 4 g. (In some countries 300 mg is the standard tablet)

Paracetamol 500 to 1000 mg every 4 to 6 hours. Maximum daily dose 4 to 6 g. Use paracetamol with caution in patients with liver damage.

WEAK OPIOIDS. Tolerance and dependence are unusual.

Codeine phosphate 30 to 120 mg, with paracetamol 500 mg, or aspirin 250 to 500 mg, every 4 to 6 hours. 30 mg of codeine is approximately equal to 650 mg of aspirin.

Dextropropoxyphene 50 to 100 mg, with aspirin 250 to 500 mg, or paracetamol 500 mg.

STRONG OPIOIDS are the main method of treating moderate and severe pain. Efficiency decreases with repeated use, so that increasing doses are needed (tolerance). Withdrawal symptoms may occur if treatment is stopped abruptly (physical dependence). Pethidine acts for 2 hours, and morphine for 4 hours.

Pethidine 50 to 100 mg orally, as a starting dose. The incidence of side-effects (tremor, twitching, agitation, convulsions) increases considerably at doses above 200 mg 3- hourly. Pethidine is not a complete alternative to morphine.

Morphine 5 to 10 mg 4-hourly orally, as a starting dose, and increasing when necessary, to 200 mg or more 4 hourly. Most patients are best controlled on 5 to 30 mg every 4 hours by the clock. This is most easily given as solutions of morphine sulphate 1 mg/ml to 20 mg/ml in 5% alcohol, or chloroform water, as a preservative, stored in a dark bottle and not exposed to sunlight. Morphine is bitter, and he may prefer to mask the taste by taking it with a drink. If necessary, let him take home a bottle of medicine containing morphine 10 mg, with 50 to 100 mg of chlorpromazine in each dose. This is a modification of the ''Brompton cocktail'. Replenish this mixture regularly, making sure he is still alive.

Constipation may be more difficult to control than pain. Almost all patients receiving regular morphine need a laxative. Start with 2 tablets of standardized senna at night and increase them to 2 tablets 2 or 3 times a day. If he is severely constipated when you first give morphine, start with suppositories or an enema.

60% of patients receiving regular morphine need an antiemetic such as chlorpromazine (which he should be on already), or prochlorperazine 5 to 10 mg 8-hourly increasing to 4-hourly, or metoclopramide 10 mg 8 hourly increasing to 4- hourly, or haloperidol 1 to 2 mg daily.

MONITOR HIS PAIN CAREFULLY. Do this within a few hours (if necessary), within a few days, and always after the first week. Make sure that treatment continues to match his pain with the minimum of side- and toxic effects. When they appear, treat them systematically, especially constipation and nausea.

CAUTION ! (1) Determine the analgesic dose for patients individually. (2) Always give drugs by mouth where you can. (3) Pain is often worse at night, so treat insomnia vigorously. (4) Exclude acute conditions that require urgent treatment. (5) Learn to use a few drugs well, and don't search desperately for one which will suit him better. (6) If you decide to allow him home with a strong opioid, his relatives must understand its dangers, and return any which is not used.

OTHER DRUGS may also be useful. The anticonvulsants carbamazepine and phenytoin also have an analgesic effect, and are effective in pain which is lancinating (shooting, stabbing). The psychotropic drugs hydroxyzine, diazepam, and amitryptyline are sometimes useful. Steroids may relieve the pain of nerve compression, cord compression, and raised intracranial pressure.

CHILDREN may also need pain relief. Manage them in the same way as adults, adjusting the doses proportionately.

DIFFICULTIES [s7]WITH TERMINAL CARE If he has BONE PAIN from secondaries, give him radiotherapy if possible. If not, give him aspirin or another NSAID.

If he is LIKELY TO GET BED SORES, because he is immobile, teach his relatives how to prevent them by regular turning (64.13).

If he ALREADY HAS BED SORES, keep him in hospital until he is weak, and not likely to live long. Turn him 2-hourly, and clean them 2-hourly with half strength saline, which need not be sterile, or with hypochlorite (''Eusol'). If they are deep, infected, and smelly, treat them as for a malignant ulcer (see below).

If he has a MALIGNANT ULCER or FUNGATING TUMOUR, control pain as above. Care for him in hospital until he is weak, and not likely to live long. Try one of these methods. (1) Apply yoghurt or honey (both readily available in some communities) 4 to 6-hourly. Honey is a good alternative to yoghurt, but may be expensive, even if it is ''from the bush'. Ask relatives to bring it. (3) If a wound is particularly smelly, apply iodoform powder between layers of dressing, and notice the dramatic improvement. (4) If none of these are available, keep the lesion wet with half-strength saline (unsterile), poured on 2-hourly, and change the dressings daily. If his relatives insist on taking him home, show them the honey or yoghurt methods.

If he suffers from INTRACTABLE VOMITING, ''drip and suck him' (4.9, 15.5) and give him an antiemetic intravenously, or as a suppository. This will relieve his nausea: intractable vomiting is a horrible way to die. You will have to give metoclopramide intravenously, but you can give him chlorpromazine, prochlorperazine, domperidone, or cyclizine as suppositories or intravenously. Avoid metoclopramide and domperidone if his vomiting is due to malignant obstruction of his gut, because they increase its motility, and may make him worse.

YOUR ACTIVE INTEREST IS ESSENTIAL! Fig. 33-3 PLASMA DRUG LEVELS FOR PAIN RELIEF. A, plasma concentration zones in relation to drug effects. These same zones are used in the diagrams which follow. B, the plasma concentration-time curves for an oral, and an intravenous dose. Notice that after an oral dose the concentration rises to a lower peak, and persists longer. C, the doses are too widely spaced to maintain analgesia. Larger doses at the same time intervals would risk toxicity. D, doses spaced satisfactorily to maintain analgesia (4-hourly for morphine). E, the effects of tolerance. The thresholds between no effect and a useful effect and between a useful effect and toxicity are rising. After Vere, from Oxford Textbook of Medicine. 34 Miscellaneous VASCULAR SURGERY