In a patient with chronic low-back pain, impaired renal function (estimated glomerular filtration rate 35 mL/min/1.73 m²), who is non‑compliant with follow-up and only takes medication when needed, and who refuses NSAIDs, acetaminophen, and epidural steroids, what is the safest pharmacologic regimen?

Management of Chronic Low-Back Pain in a Non-Compliant Patient with GFR 35 mL/min/1.73 m²

In this patient with stage 3B chronic kidney disease (GFR 35 mL/min/1.73 m²) who refuses NSAIDs, acetaminophen, and epidural steroids, the safest pharmacologic regimen is transdermal fentanyl or buprenorphine as the opioid of choice, combined with gabapentin at renally-adjusted doses (maximum 200 mg daily given the GFR <30 threshold), and scheduled dosing rather than as-needed administration. 1

Critical Renal Considerations for This Patient

• All opioids must be used with extreme caution and at reduced doses and frequency in patients with renal impairment. 1
• Fentanyl and buprenorphine via transdermal route are explicitly identified as the safest opioid choices in patients with chronic kidney disease stages 4 or 5 (eGFR <30 mL/min), and this recommendation extends to stage 3B CKD (GFR 35). 1
• NSAIDs should be avoided entirely at this GFR level, as guidelines recommend NSAID avoidance when eGFR <30 mL/min/1.73 m², and this patient's GFR of 35 places them at high risk for acute kidney injury, progressive GFR loss, electrolyte derangements, and hypervolemia. 2, 3, 4

Specific Medication Regimen

Primary Analgesic: Transdermal Opioid

• Start with transdermal fentanyl 12.5 mcg/hour patch changed every 72 hours, or transdermal buprenorphine 5 mcg/hour patch changed every 7 days. 1
• These agents avoid accumulation of toxic metabolites (morphine-6-glucuronide, hydromorphone-3-glucuronide) that occur with morphine, hydromorphone, and codeine in renal impairment. 1
• Scheduled dosing on a regular basis is mandatory rather than "as needed" administration, even though this patient only comes when wanting pain medicine. 1

Adjunctive Neuropathic Agent: Gabapentin

• Gabapentin must be dose-adjusted for GFR 35: maximum dose is 200-700 mg once daily (not the standard 1200-3600 mg/day used in normal renal function). 5, 6
• In patients with creatinine clearance less than 30 mL/min, dosing intervals must be increased, and this patient at GFR 35 requires similar caution. 1
• Monitor for sedation, dizziness, peripheral edema, and fall risk, which are more severe in patients with renal impairment. 6

Alternative Adjunctive Option: Duloxetine

• Duloxetine 30-60 mg daily can be added to target both neuropathic and inflammatory pain components, with no dose adjustment required at GFR 35. 5, 6
• This provides moderate-quality evidence for small but meaningful improvements in pain intensity and function. 5

Medications Explicitly Contraindicated

• Tramadol should be avoided or used with extreme caution: In patients with creatinine clearance less than 30 mL/min, the dosing interval must be increased to 12 hours with a maximum daily dose of 200 mg, and this patient's GFR of 35 places them at borderline risk. 7
• Morphine, hydromorphone, codeine, and oxycodone accumulate toxic metabolites in renal impairment and should be avoided. 1
• NSAIDs are absolutely contraindicated: They pose significant risk for acute kidney injury, progressive CKD, hyperkalemia, and fluid retention at this GFR level. 8, 2, 3, 4
• Systemic corticosteroids are ineffective for low back pain with or without sciatica and should not be prescribed. 5, 6, 9

Addressing Non-Compliance and "As-Needed" Medication Use

• Analgesics for chronic pain must be prescribed on a regular scheduled basis, not on an "as required" schedule, despite this patient's pattern of only seeking care when wanting pain medicine. 1
• Provide rescue doses of immediate-release opioids (fentanyl buccal or sublingual formulations) for breakthrough pain episodes, separate from the regular basal transdermal therapy. 1
• Laxatives must be routinely prescribed for both prophylaxis and management of opioid-induced constipation. 1
• Metoclopramide should be available for treatment of opioid-related nausea/vomiting. 1

Monitoring Requirements

• Renal function (serum creatinine and eGFR) must be monitored every 3-6 months or more frequently if using any potentially nephrotoxic medications. 10, 4
• Avoid concomitant nephrotoxins including NSAIDs, which this patient has already refused, and maintain hydration during any intercurrent illness. 1
• Pain intensity and functional status should be regularly assessed using visual analogue scales (VAS), verbal rating scale (VRS), or numerical rating scale (NRS). 1

Common Pitfalls to Avoid

• Do not prescribe morphine or hydromorphone as first-line opioids in renal impairment: These accumulate neurotoxic metabolites causing myoclonus, seizures, and altered mental status. 1
• Do not use standard gabapentin dosing (1200-3600 mg/day): This will cause severe sedation, falls, and cognitive impairment at GFR 35. 5, 6
• Do not allow "as-needed" dosing to continue: Chronic pain requires scheduled baseline analgesia with separate breakthrough medication. 1
• Do not prescribe NSAIDs even for short courses: At GFR 35, even brief NSAID exposure risks irreversible kidney injury. 8, 2, 3, 4