The document discusses neuropathic pain, including its pathophysiology, symptoms, causes, assessment, and treatment approaches. It provides details on pharmacological and non-pharmacological treatment options for peripheral and central neuropathic pain, including guidelines on first-line therapies such as antidepressants, anticonvulsants, and topical lidocaine. Emerging treatments currently under investigation are also mentioned.

1. NEUROPATHIC PAIN Dr.S.Anjaneyulu PG neurology

6. Neuropathic Pain vs Muscle Pain

7. Likely causes of neuropathy according to speed of onset Acute onset Inflammatory Immunological Toxic Vascular Subacute onset over weeks or months Toxic Nutritional Systemic disease Chronic onset over many years Hereditary Metabolic disease

8. Etiologies of Neuropathic Pain Low back Diabetes PHN Cancer Others

9. Goals of Neuropathic Pain Management Treat/prevent recurrence of pain-causing condition Reduce pain Improve physical/psychologic function Improve quality of life

10. Neuropathic Pain: Approach to Treatment Diagnosis Treat underlying condition/symptomatic treatment Reduce Pain Prevention (if applicable) Reduce psychological distress Improve physical functioning Improve overall quality of life

13. Risk Continuum of Pain Therapy Level of Risk Most invasive Least invasive Interventional techniques Oral medications Topical medications Psychologic/ physical approaches Injections

17. Pharmacological Treatments *: FDA approved in various neuropathic pain diseas +: FDA approved for use in severe chrnic pain

19. APPROACHES TO THE MANAGEMENT OF NEUROPATHIC PAIN Monotherapy Combinations Additional Measures B. Second-line Capsaicin Physiotherapy Lidocaine patch Occupational therapy Tizanidine Paracetamol Clonidine TENS Baclofen Acupuncture Alternative antidepressant (e.g. duloxetine) Opioid tramadol, morphine, oxycodone Opioid with TCA or AE

20. APPROACHES TO THE MANAGEMENT OF NEUROPATHIC PAIN Monotherapy Combinations C. Third-line Alternative opioids Ketamine plus opioid Ketamine Intrathecal drug delivery Neuromodulation Additional Measures : Paracetamol, TENS, Acupuncture,Physiotherapy, Occupational therapy plus Psychological support

21. Peripheral neuropathic pain ALGORITHM FOR SEQUENCE OF DIFFERENT DRUG TREATMENTS IN PERIPHERAL NEUROPATHIC PAIN Lidocaine patch NO Post-herpetic neuralgia and focal neuropathy Pregabalin/ Gabapentin Tramadol, oxycodone TCA (SNRI) TCA (SNRI) Pregabalin/ Gabapentin YES YES NO YES NO TCA contraindication TCA contraindication

22. Algorithm for the management of neuropathic pain Consider nonpharmacologic treatments (e.g. physiotherapy, psychological interventions) and, in some cases, early referral for nerve blocks to facilitate rehabilitation (e.g., complex regional pain syndrome) First Step

23. Algorithm for the management of neuropathic pain If postherpetic neuralgia or focal neuropathy, initiate topical lidocaine treatment Ineffective, partial response or other diagnosis Second Step

24. Algorithm for the management of neuropathic pain Initiate first-line drug monotherapy (Pregabalin or Gabapentin OR TCA OR SNRI) Third Step

25. Algorithm for the management of neuropathic pain Switch to alternate first-line drug monotherapy (TCA or SNRI OR Gabapentin or Pregabalin) Ineffective or not tolerated/ TCA contraindication Partial treatment response Consider adding alternate first-line drug (TCA or SNRI OR gabapentin or pregabalin) Fourth Step

26. Algorithm for the management of neuropathic pain Initiate monotherapy with Tramadol or Oxycodone Ineffective or not tolerated Partial treatment response Consider adding Tramadol or Oxycodone Fifth Step

27. Algorithm for the management of neuropathic pain Refer patient to pain specialty clinic for consideration of third-line drugs, interventional treatments and pain rehabilitation programs Ineffective or not tolerated Sixth Step

31. OPIOID ACTIVITY AT RECEPTOR SITES Mu Kappa Delta NOP NMDA Serotonergic Noradrenergic Morphine + Oxycodone + + Fentanyl ++ Tramadol + + + Methadone + - Buprenorphine (+) - - Diamorphine + + = full agonist (+) = partial agonist - = antagonist

39. Drugs in Neuropathic Pain Drug Category Type of Neuropathic Pain Daily Dosage Antidepressants Amitryptyline PHN, DPNP 10-140mg Nortryptyline PHN 10-160mg Desipramine DPNP 111 mg (avg) Citalopram DPNP 40 mg Paroxetine DPNP 40mg Bupropion DPNP, PHN 150-300mg Duloxetine DPNP 60mg Venlafaxine DPNP 150-225 mg Methadone Various neuropathic pain 10-20 mg

40. Drugs in Neuropathic Pain Anticonvulsants Gabapentin PHN, DPNP 1800-3600 mg Carbamazapine Trigeminal Neuralgia 400-800 mg Local Application Lidocaine patch, 5% PHN 3 patches/12hrs Opioids CR oxycodone PHN, DPNP 60-120mg CR morphine PHN 22 mg Tramadol DPNP 400 mg

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