What are the recommendations for pain management in a patient with impaired renal function, specifically a glomerular filtration rate (GFR) of 45?

From the Guidelines

For a patient with a GFR of 45, acetaminophen is recommended as the first-line analgesic due to its lack of need for dose adjustment, while NSAIDs should be avoided or used with caution to prevent further kidney damage. When considering opioids, it's crucial to choose options that are safer in renal impairment. According to the most recent and highest quality study 1, opioids like morphine, codeine, and tramadol are not recommended in severe renal insufficiency (GFR <30 mL/min/1.73 m2) due to accumulation of active metabolites. However, for a GFR of 45, which is considered moderate renal impairment, hydrocodone, oxycodone, and hydromorphone can be used with caution and at reduced doses. Fentanyl, having no active metabolites, is also a safer choice in patients with renal impairment 1.

Key considerations for pain management in patients with a GFR of 45 include:

• Avoiding NSAIDs due to the risk of further renal damage
• Using acetaminophen as the first-line analgesic
• Selecting opioids that are safer in renal impairment, such as fentanyl, and using them at reduced doses
• Monitoring renal function, pain control, and side effects closely to adjust the treatment plan as necessary

It's also important to note that gabapentinoids, such as gabapentin and pregabalin, may require dose reductions in patients with renal impairment to avoid adverse effects. The dose of gabapentin should be limited to 200-700mg daily in divided doses, and pregabalin should be reduced to 75-150mg daily 1. Regular monitoring and adjustments to the pain management plan are essential to ensure effective pain control while minimizing the risk of adverse effects in patients with moderate renal impairment.

From the FDA Drug Label

1. 18 Renal Impairment A clinical pharmacology study with intravenous fentanyl in patients undergoing kidney transplantation has shown that patients with high blood urea nitrogen level had low fentanyl clearance. Because of the long half-life of fentanyl when administered as fentanyl transdermal system, avoid the use of fentanyl transdermal system in patients with severe renal impairment Insufficient information exists to make precise dosing recommendations regarding the use of fentanyl transdermal system in patients with impaired renal function. Therefore, to avoid starting patients with mild to moderate renal impairment on too high of a dose, start with one half of the usual dosage of fentanyl transdermal system Regularly evaluate for signs of sedation and respiratory depression, including at each dosage increase [see Dosage and Administration ( 2.6), Use in Specific Populations ( 8.7) and Clinical Pharmacology ( 12.3) ].

For a patient with a GFR of 45, which indicates mild to moderate renal impairment, the recommendation is to start with one half of the usual dosage of fentanyl transdermal system and regularly evaluate for signs of sedation and respiratory depression. Key considerations include:

• Dose reduction: Start with half of the usual dose to avoid excessive exposure.
• Close monitoring: Regularly evaluate patients for signs of sedation and respiratory depression, including at each dosage increase.
• Caution with renal impairment: The drug's long half-life and potential for reduced clearance in renal impairment necessitate careful management. 2

From the Research

Pain Management in Patients with Impaired Renal Function

• Patients with a glomerular filtration rate (GFR) of 45 have impaired renal function, which can affect the elimination of certain opioids and their metabolites, leading to accumulation and toxicity 3.
• The choice of opioid for pain management in patients with impaired renal function should be based on the pharmacokinetic properties of the opioid, with fentanyl, alfentanil, and buprenorphine being considered safe options 3.
• Codeine and pethidine should be avoided entirely in patients with impaired renal function, while morphine should be avoided if the creatinine clearance is below 30 ml/min 3.
• Reduced-dose hydromorphone is an alternative to morphine in patients with significant renal dysfunction 4.
• Methadone, oxycodone, and tramadol should be used with caution and in reduced doses in patients with impaired renal function 3.

Recommendations for Clinical Practice

• Fentanyl is a preferred analgesic agent for critically ill patients with hemodynamic instability or for patients manifesting symptoms of histamine release with morphine or morphine allergy 4.
• Hydromorphone is an acceptable alternative to morphine for patients with significant adverse effects from morphine or severe renal dysfunction 4.
• Meperidine and intravenous codeine should be avoided if at all possible 4.
• Nonopioid analgesics, such as APAP and NSAIDs, may be useful in the management of acute pain and can reduce the dose of opioid required for adequate pain control 4.

Considerations for Patients with GFR 45

• Patients with a GFR of 45 may require reduced doses of opioids and closer monitoring of renal function 5, 6.
• Buprenorphine may be a suitable option for patients with impaired renal function, as it has a distinct benefit in improving neuropathic pain symptoms and a lower risk of respiratory depression 5.
• Fentanyl may also be a suitable option, as it has a large apparent volume of distribution and a short plasma half-life, making it less likely to accumulate in patients with impaired renal function 7.