Pain Agent Toxicities
Although included in previous guideline versions, the potential toxic effects of some pain drugs on the liver, kidneys, and other organs receive more emphasis in NCCN v.2010. This is a very significant problem in cancer patients, who may suffer from limited renal or hepatic function a result of chemotherapy or advanced age. Precautionary statements about the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and other pain-relief agents were added to NCCN v.2010:
Note that the potential side effects of chemotherapy, such as those affecting the hematologic, renal, hepatic, or cardiovascular systems, can be increased by the concomitant prescription of NSAIDs. Opioid analgesics are safe and effective alternatives to NSAIDs;
In patients at high risk for gastrointestinal toxicities, clinicians should discontinue NSAIDs if liver function studies increase to 1.5 times the upper limit of normal;
Liver function studies (alkaline phosphatase, lactate dehydrogenase, Serum glutamic oxaloacetic transaminase, Serum glutamic pyruvic transaminase) are added to routine monitoring for NSAID toxicities;
The FDA is currently evaluating daily maximum dosing of acetaminophen. Due to concerns with liver toxicity, acetaminophen should be used with caution or not used at all to prevent excess acetaminophen dosing; and
When using gabapentin and pregalbin for neuropathic pain management, dose adjustment is required for patients with renal insufficiency.
"These additions," explains Paice, "reflect the increasing guidance from the FDA about the potential toxicity of NSAIDs such as acetaminophen. Although this is still evolving, more data about renal complications are coming out, something that is critical for a cancer population." Although the FDA still recommends a maximum of 4 g of acetaminophen per day (from all sources), this dose is probably excessive for a patient who is taking acetaminophen on a daily and chronic basis. "It's a significant issue because so many products contain acetaminophen, and patients often realize how much they are taking. We wanted to draw attention to that," adds Paice.
For this reason, NCCN v.2010 also cautions that dosages of drugs such as codeine and oxycodone, which are often prescribed in combination products containing acetaminophen or acetyl salicylic acid, should be monitored for safe limits.
Medscape Oncology © 2010
Cite this: Laura A. Stokowski. Adult Cancer Pain: Part 2 -- The Latest Guidelines for Pain Management - Medscape - Dec 06, 2010.