Page 366 Guide to Pain Management in Low-Resource Settings

354 Barbara Schlisio

“Strong” opioids stop taking the opioid medication but to follow the
Strong opioids are the medication of the first choice physician’s instructions. A safe protocol would be to
in severe pain in cancer and postoperative pain as taper down the dose in several steps over about 10
well as in cancer-related dyspnea. They may also days, which safely prevents withdrawal syndromes
work to a lesser extent in neuropathic pain, but they (tearing, restlessness, tachycardia, and hypertension,
are generally not indicated for use in chronic nonspe- among other symptoms).
cific pain, such as headache, chronic back pain, fibro- Th e starting dose for morphine is approxi-
myalgia, or chronic irritable bowel syndrome. Do not mately 20–40 mg orally per day, four times a day
hesitate to use strong opioids early enough in cancer (q.i.d.). If slow-release formulations are available, once-
pain, because they can improve the patient’s qual- or twice-daily doses may be chosen. When only imme-
ity of life remarkably. There is no maximum dose for diate-release and slow-release formulations are avail-
morphine and its derivates. As a result of progress able, a fi xed schedule of opioid medication should be
of the illness, patients often—but not always—re- combined with an on-demand dose, which should be
quire an increase of the dose over the course of the approximately 10–20% of the cumulative daily opioid
disease. Dose increases do not mean tolerance or ad- dose. For example, in a patient taking 20 mg morphine
diction, but reflect progressive tissue damage most of q.i.d. (80 mg daily consumption), 10 mg of morphine
the time. Other causes of increasing dose demands should be allowed as an extra dose to be taken on de-
are a change in pain quality (development of neuro- mand in situations of increased pain (“breakthrough
pathic pain instead of nociceptive pain) or concomi- pain”). Th e patient should observe a minimum time
tant anxiety or depressive disorders. The other causes interval of 30 to 45 minutes before using another de-
mentioned have to be diagnosed correctly to be able mand dose. According to the number of daily demand
to treat them specifically with coanalgesics or non- doses, the caregiver may change the constant basal
pharmacological interventions. dose of morphine. In a patient needing no demand
Nausea and vomiting, drowsiness, dry mouth, doses at all, the basal dose may be reduced by 25%, in a
miosis, and constipation occur very frequently in pa- patient requiring one to four doses the scheme should
tients taking strong opioids. If nausea and vomiting stay unchanged, and in a patient requiring more than
persist, or delirious symptoms develop, a change to four demand doses the basal opioid dose should be
another opioid (“opioid rotation”) usually controls the increased. For example, in a patient with a basal mor-
problem. Constipation will occur in all opioids and re- phine dose of 4 times 20 mg of morphine requiring on
quires therefore constant prophylaxis, while antiemetic average daily 6 times 10 mg of morphine on demand,
drugs should be used prophylactically for only a short the basal dose of morphine should be increased to 4
period of time (7–10 days), until tolerance has devel- times 30 mg (and the demand dose should be in-
oped. Consider, and explain to the patient, that opioids creased to 20 mg).
are not toxic to any organ. Hence there are no contra- Th e same approach should be used for the treat-
indications, except in patients with a history of allergic ment of dyspnea (even in patients not suff ering from
reactions (very rare). Other contraindications such as pain). Opioids decrease the “breathing force” by a right-
chronic obstructive pulmonary disease or renal func- ward shift of the CO response curve, eff ectively reduc-
2
tion impairment do not mean that opioids should be ing the subjective “air hunger.”
withheld, but that their dose must be titrated slowly and All pure μ-opioid agonists are interchangeable
carefully to eff ect. and combinable and diff er only in their subjective side-
Strong opioids may even be used in pregnancy, eff ect profi le (which is not predictable individually) and
but close cooperation with the pediatrician or neona- in their relative potency (not their absolute potency).
tologist is necessary to cope with respiratory depression Th e equianalgesic doses for 10 mg morphine orally are 2
and/or opioid dependency in the neonate. mg hydromorphone, 5 mg oxycodone, 100 mg of trama-
Dependency occurs in most patients when dol, and 1.5 mg of levomethadone.
more than about 100 mg of morphine is given daily Th e equianalgesic doses of all opioids depend-
for more than 3 weeks. To avoid withdrawal syn- ing on the application route must be known. In mor-
drome, the patient must be instructed never to just phine, these are: