Analgesics should be provided on a time-contingent basis to provide a steady state of analgesia; when needed, medication should be available to manage breakthrough pain. Adjuvant medications such as tricyclic antidepressants, gabapentin, and other centrally acting pain medications should be considered, particularly in light of the developing understanding of the common neuropathic mechanisms involved in cancer pain (see list of pain mechanisms).[6,7,8] Regular assessment of pain and modification of pain medications are necessary.
Transdermal fentanyl is widely used for extended duration therapy in the management of pain in the outpatient setting. Cyclooxygenase-2 (COX-2) is upregulated in mucositis; therefore, COX-2 inhibitors represent potential agents that may affect pain and evolution of mucositis.
Adjuvant medications should be used in addition to analgesics. Patients who experienced neuropathic cancer pain and received amitriptyline in addition to morphine were studied in a randomized controlled trial.[Level of evidence: I] Limited additional analgesic effect and increased drowsiness, confusion, and dry mouth were observed; however, the central actions of amitriptyline may improve sleep.
Gabapentin is a voltage-sensitive sodium and calcium channel blocker that is used for management of a variety of pain conditions and may improve pain control when used in addition to morphine in cancer patients. Drugs that affect the N-methyl-D-aspartate receptor may affect neuropathic pain; gabapentin is one of these and is well tolerated. Other agents that may be used in pain management include the following:
- Alpha-2 adrenergic receptor agonists.
Addiction in opioid therapy is not generally a concern for cancer patients; the focus should be on escalating to stronger opioids as needed (based on assessment) and using adjuvant approaches to provide adequate pain relief. However, the clinician always should be cognizant of potential drug-seeking behavior by the patient.
Tolerance and physical side effects such as constipation, nausea, vomiting, and mental clouding occur with opioids and should be managed prophylactically, if possible. Stool softeners and other approaches to bowel management should be initiated along with the initial opioid prescription. Adequacy of the approach should be assessed regularly.
Nonpharmacologic pain management strategies