Cancer pain & opioids flashcards
28 high-yield MRCP Part 1 cards from the Intellect Medicos Geriatrics & Palliative Care course. Try to answer each question before you open it — then study them properly with spaced repetition, which brings each card back just before you would forget it.
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______ pain is sudden, transient pain that occurs despite adequate baseline analgesia.
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Breakthrough
Why? It needs an immediate-release PRN dose on top of the regular modified-release opioid.
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Name three psychosocial factors that increase cancer pain perception.
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Any three of: anger, anxiety, grief, depression, fatigue/insomnia, boredom, social isolation, lack of understanding.
Why? Total pain has physical, psychological, social and spiritual parts; sleep, company, relaxation and clear information reduce it.
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What is the NICE starting regimen for strong opioids in a palliative patient with no comorbidities (normal renal and hepatic function)?
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Oral modified-release morphine 20–30 mg/day plus immediate-release oral morphine 5 mg PRN for breakthrough pain.
Why? NICE CG140: e.g. MR morphine 10–15 mg twice daily, with 5 mg IR morphine for rescue doses while titrating. Oral MR morphine is the first-line maintenance treatment.
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How is the breakthrough (PRN) opioid dose calculated?
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One-tenth to one-sixth of the total 24-hour regular opioid dose (the course notes use one-sixth).
Why? Give it as immediate-release of the same opioid when breakthrough pain occurs, every 2–4 hours as needed.
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A woman with metastatic breast cancer takes MR morphine 60 mg twice daily. Using the one-sixth rule, what is her immediate-release morphine breakthrough dose?
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20 mg PRN.
Why? 60 mg BD = 120 mg/24 h; one-sixth of 120 mg = 20 mg.
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Which drug must be prescribed for everyone started on a regular strong opioid?
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A laxative (e.g. senna, or macrogol).
Why? Opioid constipation is almost universal and tolerance to it does not develop.
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By how much should a strong opioid dose be increased when pain is not controlled?
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By 30–50%.
Why? Smaller steps under-treat pain; larger steps risk toxicity.
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A man takes MR morphine 20 mg twice daily and has needed two 5 mg doses of IR morphine in each of the last few days. What should his new regular MR morphine dose be?
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MR morphine 25 mg twice daily (with a new PRN of about 8 mg, one-sixth of 50 mg, rounded to a practical dose).
Why? Add regular (40 mg) and PRN (10 mg) use = 50 mg/24 h, then give half as each 12-hourly MR dose. This is a 25% rise, within the 50% limit.
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When re-titrating opioids, if the new total daily dose would be more than ______ above the previous dose, increase by only that amount.
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50%
Why? This caps each step and avoids opioid toxicity from a large jump.
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How do you convert an oral codeine or tramadol dose to the equivalent oral morphine dose?
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Divide by 10.
Why? Both are about 10 times weaker than oral morphine, e.g. codeine 240 mg/24 h ≈ oral morphine 24 mg/24 h.
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To convert oral morphine to subcutaneous morphine, divide by ______; to subcutaneous diamorphine, divide by 3.
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2
Why? SC morphine is twice and SC diamorphine three times as potent as oral morphine, e.g. oral morphine 15 mg ≈ SC diamorphine 5 mg.
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To convert oral morphine to subcutaneous morphine, divide by 2; to subcutaneous diamorphine, divide by ______.
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3
Why? SC morphine is twice and SC diamorphine three times as potent as oral morphine, e.g. oral morphine 15 mg ≈ SC diamorphine 5 mg.
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According to the course conversion chart, how do you convert oral morphine to oral oxycodone?
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Divide by 1.5 (oral oxycodone is about 1.5 times as potent as oral morphine).
Why? e.g. oral morphine 7.5 mg ≈ oral oxycodone 5 mg. SC oxycodone is twice as potent as oral oxycodone.
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A fentanyl 25 microgram/hour patch is roughly equal to ______ oral morphine per 24 h; a 12 microgram/hour patch to 30 mg.
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60 mg
Why? Transdermal fentanyl is about 100 times as potent as oral morphine.
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A fentanyl 25 microgram/hour patch is roughly equal to 60 mg oral morphine per 24 h; a 12 microgram/hour patch to ______.
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30 mg
Why? Transdermal fentanyl is about 100 times as potent as oral morphine.
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A buprenorphine 10 microgram/hour patch is roughly equivalent to how much oral morphine per 24 hours?
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24 mg oral morphine per 24 h.
Why? A 5 microgram/hour patch ≈ 12 mg/24 h; the conversion scales linearly.
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How potent is SC alfentanil compared with SC diamorphine?
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About 10 times more potent (SC alfentanil 1 mg ≈ SC diamorphine 10 mg).
Why? Alfentanil is used in syringe drivers in severe renal impairment, so the conversion matters.
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Which opioid side effect does NOT usually improve with continued use?
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Constipation.
Why? Tolerance develops to nausea and drowsiness over days, but not to the gut effect, so laxatives are continued.
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Name four signs of opioid toxicity.
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Any four of: drowsiness/sedation, confusion or hallucinations, pinpoint pupils (miosis), respiratory depression, myoclonus, hypotension, bradycardia, urinary retention.
Why? In palliative care, new drowsiness, confusion or myoclonus are the early clues, often after a dose rise or worsening renal function.
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What is the antidote for opioid toxicity?
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IV naloxone.
Why? Naloxone is a competitive opioid receptor antagonist. Its half-life is shorter than most opioids, so repeat doses or an infusion may be needed.
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Why is morphine risky in renal impairment?
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Its active metabolites (morphine-3- and -6-glucuronide) are renally excreted and accumulate.
Why? Accumulation causes sedation, respiratory depression and neurotoxicity (myoclonus, confusion, hallucinations).
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Which opioids are preferred in severe renal impairment (eGFR below 30)?
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Alfentanil, fentanyl or buprenorphine.
Why? They are mainly metabolised by the liver and have little renally cleared active metabolite, so they accumulate far less than morphine in renal failure.
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According to the notes, which strong opioid can be used in mild to moderate renal impairment (eGFR 30–60)?
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Oxycodone (at a reduced dose).
Why? Oxycodone has fewer active renally cleared metabolites than morphine. The notes also list meptazinol, a partial agonist rarely used in UK palliative care.
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Which adjuvant analgesics are used for neuropathic cancer pain?
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Amitriptyline, duloxetine, gabapentin or pregabalin (the course notes name a tricyclic or gabapentin).
Why? They act on nerve-pain pathways that respond poorly to opioids alone. NICE CG173 offers a choice of these four as initial treatment.
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Which drug is used for intestinal colic in palliative care?
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Hyoscine butylbromide.
Why? It is an antimuscarinic antispasmodic that relaxes gut smooth muscle and does not cross the blood–brain barrier.
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Which adjuvant is used for pain from liver capsule stretch (hepatic metastases) or raised intracranial pressure?
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Dexamethasone.
Why? It reduces tumour-related oedema and swelling.
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Which drugs are used for painful muscle spasm in palliative care?
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Diazepam or baclofen.
Why? Both reduce skeletal muscle tone (GABA-mediated).
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Name the three main treatment options for metastatic bone pain.
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Strong opioids, bisphosphonates and radiotherapy.
Why? Single-fraction palliative radiotherapy gives good relief for localised bone pain; bisphosphonates help widespread bone metastases.