What are the best analgesics to commence on a young patient with acute on chronic radicular pain from L5 (lumbar 5) nerve root compression, already on Panadol (paracetamol), Pregablin (pregabalin), Venlafaxine, Buprenorphine (buprenorphine) patch, and Tapentadol?

Management of Acute on Chronic Radicular Pain from L5 Nerve Root Compression

For a young patient with acute on chronic radicular pain from L5 nerve root compression already on multiple analgesics, adding a nonsteroidal anti-inflammatory drug (NSAID) would be the most appropriate next step in management.

Current Medication Analysis

The patient is currently on:

• Panadol (paracetamol): Limited evidence for efficacy in radicular pain 1
• Pregabalin: Used for neuropathic pain component 1
• Venlafaxine: SSNRI with some efficacy in neuropathic pain 1
• Buprenorphine patch: Opioid with modest effect on chronic low back pain 1
• Tapentadol: Dual-action analgesic (μ-opioid receptor agonist and noradrenaline reuptake inhibitor) 2

Recommended Approach for Radicular Pain

First-line Options to Consider

• NSAIDs are recommended as first-line treatment for acute radicular pain due to their moderate efficacy and better safety profile compared to other options 3
• For radicular low back pain specifically, evidence for NSAIDs is limited but they represent a reasonable option with fewer adverse effects than continuing to escalate opioid therapy 1

Second-line Options

• Duloxetine could be considered as it has shown small improvements in pain intensity and function in chronic low back pain compared to placebo (moderate-quality evidence) 1
• Combination therapy with pregabalin and tramadol has demonstrated synergistic effects in neuropathic pain models 4, 5

Medications to Avoid

• Benzodiazepines should be avoided as low-quality evidence showed diazepam resulted in a lower likelihood of pain improvement at 1 week compared with placebo in radicular pain 1
• Systemic corticosteroids show no significant difference in pain compared to placebo for radicular low back pain (moderate-quality evidence) 1

Treatment Algorithm

1. Add an NSAID (preferably COX-2 selective to reduce GI side effects) 1, 3

   • Monitor for GI, renal, and cardiovascular adverse effects

2. If inadequate response after 1-2 weeks:

   • Consider switching venlafaxine to duloxetine (60mg daily) which has better evidence for pain relief in this context 1
   • Duloxetine has shown consistent efficacy in peripheral neuropathic pain with small improvements in pain intensity and function 1

3. For breakthrough pain episodes:

   • Consider small amounts of short-acting opioid analgesics if the patient is at low risk for opioid misuse 1
   • Non-pharmacological interventions should be incorporated (physical therapy, manipulation) 1

4. If pain remains uncontrolled:

   • Consider interventional approaches such as pulsed radiofrequency treatment 6, 7
   • Tapentadol dose optimization may be beneficial as it has shown efficacy in both nociceptive and neuropathic components of pain 6, 2

Cautions and Considerations

• The patient is already on multiple centrally-acting medications (pregabalin, venlafaxine, buprenorphine, tapentadol), increasing the risk of CNS side effects including sedation 1
• Adding more opioids is unlikely to provide significant additional benefit as moderate-quality evidence shows no differences among different long-acting opioids for pain or function 1
• Lumbar radiculopathy appears relatively refractory to many first and second-line medications, including opioids 3
• Polypharmacy increases risk of adverse events and drug interactions, so careful monitoring is essential 1

Monitoring Recommendations

• Assess pain relief and functional improvement after 1-2 weeks of therapy 1
• Monitor for adverse effects, particularly sedation, dizziness, and constipation 1
• Evaluate for improvement in quality of life and sleep 6
• Consider tapering medications that show limited benefit to reduce polypharmacy 1