A Practical Approach to Using Adjuvant Analgesics in Older Adults

Russell K. Portenoy, MD

Disclosures

J Am Geriatr Soc. 2020;68(4):691-698. 

In This Article

Drugs Used in Cancer Pain Management

In populations with cancer, adjuvant analgesics may target opioid-refractory bone pain and pain associated with bowel obstruction.

Drugs Used for Bone Pain

When bone pain is focal, radiation is effective, and several percutaneous invasive techniques, such as radiofrequency ablation, may be considered. For opioid-refractory multifocal bone pain, however, a systemic bone-targeting therapy is needed. The most important drugs are osteoclast inhibitors and include the bisphosphonates and denosumab. These drugs are also widely used prophylactically to reduce the risk of skeletal-related events (SREs) other than pain, such as fracture and hypercalcemia.[67] Although calcitonin also is an osteoclast inhibitor and may have utility in the treatment of pain related to osteoporotic vertebral fractures,[68] it is not used for these cancer-related indications.[69]

Bisphosphonates such as zoledronate, alendronate, ibandronate, and pamidronate reduce bone pain.[70] Acute adverse effects, including a flulike syndrome, epigastric pain, and reduced renal function, usually are tolerated, and serious long-term effects, including serious osteonecrosis of the jaw and atypical femoral fracture, are very uncommon.[71] Denosumab, a human monoclonal antibody that inhibits osteoclast activity by binding to receptor activator of nuclear factor-κB ligand, also reduces SREs, including pain, and has an adverse-effect profile similar to the bisphosphonates.[72,73] It may delay complications from bone disease longer than a bisphosphonate and be a cost-effective option in some cancer patients.[73,74]

Radioisotope drugs, such as strontium-89 and samarium-153, link a bone-seeking phosphonate to a radioisotope and are used for multifocal bone pain.[75] Treatment requires sourcing of the radioisotope and the availability of skilled personnel and facilities; for this reason, treatment is limited to a highly selected subset of patients.

Drugs Used for Pain and Other Symptoms in Bowel Obstruction

When malignant bowel obstruction cannot be relieved surgically or through stenting, pain and other symptoms may be addressed using an opioid, glucocorticoid, proton pump inhibitor (PPI), antiemetic, anticholinergic drug, and/or somatostatin analog.[76] Antisecretory drugs, including the PPIs, anticholinergics such as scopolamine hydrobromide and glycopyrrolate, and somatostatin analogs (octreotide and lanreotide), could potentially relieve pain by reducing distention. The data supporting these drugs are limited and conflicting, however, and there is no consensus about the best approach. A systematic review found no clear benefit from the somatostatin analogs,[77] and with these negative findings and high cost, some palliative care specialists consider a trial only when symptoms cannot be controlled with other drugs.

In conclusion, chronic pain is a common cause of symptom distress and functional impairment in older adults. Multiple treatment modalities should be considered including nonpharmacologic and pharmacologic therapies. The adjuvant analgesics offer numerous options. Challenges include drug selection in the context of limited evidence and the need to ensure safe therapy given the varied adverse-effect profiles of these drugs. Cautious use of these drugs based on the best evidence and clinical experience may help address difficult pain syndromes in carefully selected older adults.

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