General Considerations
General considerations for genitourinary pain management follow
the same principles of pain management elsewhere. For nonmalignant acute pain, medical
management is the first choice. narcotics and non-narcotic medications such as acetaminophen,
aspirin, and NSAIDs are indicated for the control of acute pain. When oral administration
is not feasible, parenteral administration of narcotics should be used. Patient-controlled
epidural analgesia or continuous epidural infusion produces segmental dose-related
analgesia and prevents atelectasis. The use of lipophilic versus hydrophilic narcotics
depends on the segmental level of epidural catheter placement. Intravenous patient-controlled
analgesia should be the next option. Meperidine should be avoided in patients with
compromised renal function because the half-life of normeperidine (metabolite of
meperidine that lowers the seizure threshold and induces CNS excitability) is significantly
prolonged. Hydromorphone, a semisynthetic opioid, is recommended for patients with
renal failure because of the lack of identifiable metabolites. The antiprostaglandin
effect of NSAIDs affects the regulation of renal blood flow in susceptible patients.
Therefore, patients requiring long-term NSAIDs should be appropriately monitored
for renal function.
Interventional techniques are an integral part of pain control
in chronic nonmalignant and malignant pain syndromes. Continuous epidural infusion
of opioids causes
minimal fluctuation of drug levels in cerebrospinal fluid. Before consideration
of a tunneled epidural catheter, pain should be treated aggressively with sustained-release
morphine preparations, methadone, and fentanyl transdermal patches to optimize the
medication requirement. If intractable pain persists despite aggressive systemic
opioids and adjuvant drug therapy, treatment with an implantable drug delivery system
should be considered. Because of the safety, efficacy, and relative ease of intraspinal
administration of opioids for the control of intractable pain resulting from metastatic
disease, implantable intrathecal and epidural drug administration systems are being
used increasingly.
