Experimental therapies

Many therapies have been anecdotally reported to provide relief of peripheral neuropathy pain and several of these have been tested in small studies.

Studies have yielded conflicting data about topical capsaicin (Axsain, Zacin), a chili-pepper derivative that may work by inhibiting pain signalling pathways. In a randomised controlled study of 26 patients with HIV-associated neuropathy, it did not improve symptoms more than did placebo after one week.1 However, an open-label study found that a high-concentration capsaicin patch reduced neuropathic pain by 40%.2 A more recent study showed that an 8% capsaicin patch relieved neuropathy pain in a controlled trial that included over 300 HIV-positive patients with neuropathy, 18% of whom were taking d4T or ddI. Patients in the highest-dose capsaicin arm reported a pain score reduction of 23%, compared with 11% in the placebo arm; the patch was applied for 90 minutes at a time and provided relief for long as 12 weeks.3

In a pilot study of another topical preparation, 5% lidocaine cream, 20 out of 27 patients reported moderate or substantial pain relief.4 In a controlled trial with 64 patients, lidocaine did not perform better than placebo.5 One small controlled study found that topical application of aspirin reduced peripheral neuropathy pain more than placebo.6

Memantine (Ebixa), a drug approved in Europe for treatment of Parkinson’s disease and in the United States for Alzheimer’s dementia, has been shown to relieve peripheral neuropathy pain in diabetics.7

Flecainide (Tambocor), used to treat pain due to cancer-related neuropathy, has also shown some effectiveness in a trial of HIV-positive people.8 Another agent, nimodipine (Nimotop), counteracted the development of neuropathy in a study of diabetic rats.9 Although mexiletine (Mexitil), a drug used to treat heart rhythm disturbances, appeared to provide relief in one uncontrolled trial, it performed no better than amitriptyline or placebo in a 145-person controlled trial, and it caused dose-limiting side-effects.10

Biological agents have also been tested as therapies for peripheral neuropathy. In one study, low doses of erythropoietin (Eprex, NeoRecormon), a hormone used to stimulate red-blood-cell production, appeared to prevent nerve damage due to HIV infection and treatment with ddC (zalcitabine, Hivid).11 Synthetic thyroid hormone has been shown to regenerate nerve axons in animal studies.12

Recombinant human nerve growth factor (NGF) has been used to treat HIV-associated and diabetic peripheral neuropathy. In one study of 270 people with HIV-associated neuropathy, it reduced pain and improved sensitivity.13 A 200-person study found that while NGF alleviated symptoms of neuropathic pain, it produced no evidence of improvement as measured by neurological examination or nerve fibre density tests.14 Although phase II trials suggested NGF reduced symptoms associated with both diabetic and HIV-associated neuropathy, a randomised phase III study with more than 1,000 participants failed to show a benefit of NGF over placebo after 48 weeks.15 The manufacturer discontinued development of the drug in 1999.

References

  1. Paice JA et al. Topical capsaicin in the management of HIV-associated peripheral neuropathy. J Pain Symptom Manage 19: 45-52, 2000
  2. Simpson D et al. Novel high-concentration capsaicin patch for the treatment of painful HIV-associated distal symmetrical polyneuropathy: results of an open-label trial. Eleventh Conference on Retroviruses and Opportunistic Infections, San Francisco, abstract 490, 2004
  3. Simpson D et al. Controlled study of high-concentration capsaicin patch for painful HIV-associated distal sensory polyneuropathy. 13th Conference on Retroviruses and Opportunistic Infections, Denver, abstract 79, 2006
  4. Dorfman D et al. Treatment of painful distal sensory polyneuropathy in HIV-infected patients with a topical agent: results of an open-label trial of 5% lidocaine gel. AIDS 13: 1589-1591, 1999
  5. Estanislao L et al. A randomized controlled trial of 5% lidocaine gel for HIV-associated distal symmetric polyneuropathy. J Acquir Immune Defic Syndr 37: 1584, 2004
  6. Cergnul J et al. Topical application of aspirin / diethyl ether in treatment of painful distal sensory polyneuropathy in HIV-positive individuals: a randomized, double-blind, crossover placebo-controlled study. Eighth Conference on Retroviruses and Opportunistic Infections, Chicago, abtract 601, 2001
  7. Sang CN et al. Dextromethorphan and memantine in painful diabetic neuropathy and postherpetic neuralgia: efficacy and dose-response trials. Anesthesiology 96: 1053-1061, 2002
  8. Cameron J et al. A phase II pilot study of flecainide for neuropathic pain in HIV / AIDS. 35th Annual Meeting of the American Society of Clinical Oncology, Atlanta, abstract 2323, 1999
  9. Kappelle AC et al. The Ca2 antagonist nimodipine counteracts the onset of an experimental neuropathy in streptozotocin-induced diabetic rats. Br J Pharmacol 111: 887-893, 1992
  10. Kieburtz K et al. A randomized trial of amitryptiline and mexiletine for painful neuropathy in HIV infection. Neurology 51: 1682-1688, 1998
  11. Keswani SC et al. Erythropoietin is neuroprotective in models of HIV sensory neuropathy. Neurosci Lett 371: 102-105, 2004
  12. Voria I et al. Improved sciatic nerve regeneration by local thyroid hormone treatment in adult rat is accompanied by increased expression of SCG10. Exp Neurol 197: 258-267, 2006
  13. McArthur J et al. A phase II trial of recombinant nerve growth factor for sensory neuropathy associated with HIV infection. Neurology 54: 1080-1088, 2000
  14. Schiffito G et al. Long-term treatment with recombinant nerve growth factor for HIV-associated sensory neuropathy. Neurology 57: 1313-1316, 2001
  15. Apfel SC et al. Nerve growth factor for the treatment of diabetic neuropathy: what went wrong, what went right, and what does the future hold? Int Rev Neurobiol 50: 393-413, 2002
Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap
close

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.