A 52-year-old man with type 2 diabetes mellitus presents to the pain clinic with a 6-month history of burning pain in both feet, worse at night, affecting his sleep. Examination reveals diminished vibration sense and absent ankle reflexes bilaterally. Nerve conduction studies confirm demyelinating sensorimotor polyneuropathy. He has already tried topical capsaicin without relief. His current medications include metformin, lisinopril, and atorvastatin. Which of the following is the most appropriate first-line pharmacological agent for his neuropathic pain?

Explanation

## Neuropathic Pain Management in Diabetic Polyneuropathy **Key Point:** Pregabalin and gabapentin are first-line agents for neuropathic pain, including diabetic peripheral neuropathy (DPN), with strong evidence from randomized controlled trials. ### Mechanism of Action Pregabalin is a gabapentinoid that binds to the α~2~δ subunit of voltage-gated calcium channels, reducing neurotransmitter release and neuropathic pain transmission. ### Evidence Base for DPN - FDA-approved specifically for diabetic peripheral neuropathy - NNT (Number Needed to Treat) ≈ 4–5 for 50% pain reduction - Effective for both positive symptoms (burning, pain) and sleep disturbance - Well-tolerated with predictable pharmacokinetics ### Dosing in DPN | Parameter | Details | | --- | --- | | Starting dose | 75 mg once daily or 50 mg thrice daily | | Target dose | 300 mg/day in divided doses | | Maximum dose | 600 mg/day | | Renal adjustment | Required (CrCl <60 mL/min) | **Clinical Pearl:** Pregabalin also improves sleep quality in neuropathic pain patients, addressing both pain and the patient's sleep disturbance. **High-Yield:** First-line agents for neuropathic pain are gabapentinoids (pregabalin, gabapentin) and SNRIs (duloxetine). NSAIDs and opioids are not first-line for neuropathic pain. ### Why Pregabalin Over Alternatives 1. **Gabapentin** — equally effective but pregabalin has more predictable kinetics 2. **Duloxetine** — also first-line; choice depends on comorbidities (this patient has no contraindications to either) 3. **Tramadol** — second-line; reserved for inadequate response to gabapentinoids 4. **Morphine** — third-line; opioids are not first-line for neuropathic pain due to tolerance and abuse risk 5. **NSAIDs** — ineffective for neuropathic pain; appropriate only for nociceptive pain [cite:Harrison 21e Ch 384]