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Unit I: Pain and Symptom Management
Module 3, Part 7. Pain Management: Answers to Case Studies

ANSWERS TO PROBLEMS:	For all of these cases, remember nonpharmacologic approaches as a possibility and remember to consider possible barriers to good use of pain interventions.
Case 1	Mrs D is a 45-year-old attorney who has breast cancer metastatic to bone. She is comfortable on a continuous infusion of morphine at 6 mg/h SC. Your goal is to change to oral medications before discharging her home. What should your prescription be? Answer Figure out total daily dose of IV morphine 6 mg/h x 24 hours = 144 mg/d IV morphine Set up a ratio using values from the Equianalgesic Dosage Table 3 mg oral morphine = 1 mg IV morphine X mg/d oral morphine 144 mg/d IV morphine Solve for X X = 432 mg/d oral morphine Divide by 2 for bid formulation of extended-release morphine, or divide by 6 for immediate-release morphine administered every 4 hours. Sig: 200 mg extended-release morphine po bid, or 70 mg immediate-release morphine po q 4 h around the clock (RTC) Also prescribe a breakthrough dose of 5% to 16.7% of total daily dose Sig: 20–70 mg immediate-release morphine po q 1 h prn Do not forget a stimulant laxative!
Case 2	Mr T is a 73-year-old man with lung cancer, a malignant pleural effusion, and chronic chest pain. He has undergone therapeutic thoracentesis and pleurodesis. He is currently receiving meperidine, 75 mg IM q 6 h, for pain. You want to change to oral morphine. Without adjusting for cross-tolerance, what dose and schedule would you choose? Answer Figure out total daily dose 4 x 75 mg IM meperidine = 300 mg/d IM meperidine Set up ratio from the Equianalgesic Dosage Table 50 mg IM meperidine = 15 mg po morphine 300 mg/d IM meperidine X mg/d po morphine Solve for X X = 90 mg/d po morphine Decide on schedule and formulation Sig: sustained-release morphine, 45 mg po bid Remember breakthrough dose Sig: 5–15 mg po immediate-release morphine q 1 h prn Remember the stimulant laxative!
Case 3	Ms. M is a 41-year-old teacher who has ovarian cancer with ascites and has been taking 2 tablets of acetaminophen/hydrocodone (500 mg/5 mg) every 4 hours and 1 tablet of acetaminophen/oxycodone (325 mg/5 mg) every 6 hours for pain relief. Morphine makes her nauseated. You are concerned about acetaminophen toxicity and want to change to an alternative oral approach. Without adjusting for partial cross-tolerance, what dose of hydromorphone would you choose? Answer Figure out total daily dose of each opioid 2 tablets x 5 mg hydrocodone/tablet x 6 = 60 mg/d hydrocodone 1 tablet x 5 mg oxycodone/tablet x 4 = 20 mg/d oxycodone Set up ratios from the Equianalgesic Dosage Table 15 mg oral hydrocodone = 4 mg oral hydromorphone 60 mg/d oral hydrocodone X1 mg/d oral hydromorphone 10 mg oral oxycodone = 4 mg oral hydromorphone 20 mg/d oral oxycodone X2 mg/d oral hydromorphone Solve for X in each case X1 = 16 mg/d oral hydromorphone X2 = 8 mg/d oral hydromorphone Add X1 and X2 together for a total of 24 mg/d oral hydromorphone Decide on schedule: Sig: Hydromorphone, 4 mg po q 4 h RTC Don’t forget breakthrough medication dosing: Sig: Hydromorphone, 1–4 mg po q 1 h prn Do not forget a stimulant laxative!
Case 4	Mrs. A is hospitalized and receiving adequate pain control with meperidine, 120 mg intramuscularly every 3 hours. She is now able to take nutrition and medications by mouth. Correcting 25% for incomplete cross-tolerance, what dose and schedule of oral hydromorphone would you prescribe to provide her with an approximately equal amount of analgesia? Answer c. 8 mg po q 4 h Calculating the Answer Figure out total daily dose of each opioid 120 mg x 8 = 960 mg/d IM meperidine Set up ratios from the Equianalgesic Dosage Table 50 mg IM meperidine = 4 mg oral hydromorphone 960 mg/d IM meperidine X mg/d oral hydromorphone Solve for X X = 76.8 mg/d po hydromorphone Decide on schedule 12 mg po q 4 h Adjust down 25% for incomplete cross-tolerance (12 x 0.75 = 9; tablets come in 2 or 4 mg size, so 8 mg is best choice) Sig: Hydromorphone, 8 mg po q 4 h
Case 5	Mr. B has been taking 3 capsules containing oxycodone (5 mg per capsule) and acetaminophen every 3 hours at home for relief of bone pain from metastatic lung cancer. He is now admitted to the hospital with a chemotherapy-induced aplasia. You do not want him taking an antipyretic (acetaminophen). Without correcting for partial cross-tolerance, how much oral morphine elixir would you prescribe to provide analgesia similar to that which he received from the oxycodone? Answer d. 30 mg po q 4 h Calculating the Answer Figure out total daily dose of opioid 3 tablets x 5 mg oxycodone/tablet x 8 = 120 mg/d oxycodone Set up ratio from the Equianalgesic Dosage Table 10 mg oral oxycodone = 15 mg oral morphine 120 mg/d oral oxycodone X mg/d oral morphine Solve for X X = 180 mg/d oral morphine Decide on schedule Sig: Morphine, 30 mg po q 4 h RTC
Case 6	Mrs. C has been taking codeine, 60 mg by mouth every 4 hours, and methadone, 40 mg orally every 6 hours, to adequately control abdominal pain from bulky retroperitoneal metastases. She is now admitted with a chemotherapy-induced stomatitis. Your attending physician suggests that you place her on a constant infusion of intravenous morphine. Without adjusting for partial cross-tolerance, what hourly rate of intravenous morphine will you choose to continue to keep her pain well controlled? Answer c. 4 mg/h A way to calculate the Answer From the Equianalgesic Dosage Table, methadone, 40 mg po = 20 mg IV = morphine, 20 mg IV Codeine, 60 mg po = 40 mg IV = morphine, 3 mg IV Total daily dose: Methadone, 40 mg po X 4 = morphine, 80 mg IV Codeine, 60 mg po X 6 = 18 mg IV Total morphine/24 h = 80+18 = 98 mg 98 mg ÷ 24 h = 4 mg/h
Case 7	John is a 40-year-old accountant with AIDS (acquired immunodeficiency syndrome). His most recent T4 count is 34. He has noted a burning pain in his hands and feet for the past 2 years. It initially appeared after he began zalcitabine (ddC) in addition to zidovudine (AZT) and resolved when the ddC was discontinued. However, the past 6 months the pain has returned. It is severe, keeps him awake at night, and is associated with numbness of his feet. He has trouble buttoning his shirt. How would you manage John’s pain? Answer Consider opioids, tricyclic antidepressants, gabapentin, and other adjuvants for neuropathic pain.
Case 8	Sarah is a 73-year-old attorney who has breast cancer with metastases to bone. She was treated with three cycles of AC (adriamycin, cyclophosphamide) without response. Pain persists, even after 2 months of tamoxifen. How would you manage Sarah’s pain? Answer Consider NSAIDs, steroids, and bisphosphonates as well as radiation.
Case 9	David is a 67-year-old farmer with colon cancer metastatic to liver. He has complained of increasing right upper quadrant pain. Examination reveals a tender liver, but no shifting dullness to percussion of his abdomen. How would you manage David’s pain? Answer Consider opioid analgesics and steroids to decrease capsular stretch.
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