The American Academy of Neurology (AAN) recently issued a new guideline for the treatment of diabetic neuropathy, also called diabetic nerve pain. The condition is the result of nerve damage caused by high blood-sugar levels associated with diabetes. According to the National Institute of Diabetes and Digestive and Kidney Diseases, 60 to 70 percent of people diagnosed with diabetes also have neuropathy, with the level of risk rising with age and the longer one has diabetes.
The experts interviewed by Neurology Now say the AAN guideline adequately summarizes most of the current treatment options, although some believe it is too heavily weighted towards pharmaceutical remedies.
“The first thing I still do is tell my patients with diabetic neuropathy to start exercising. After all, what's better than having your own body remodel your nerves?” says Thomas Chelimsky, M.D., professor of neurology at Case Western Reserve University School of Medicine in Cleveland, OH, and Director, Autonomic Division, University Hospitals of Cleveland.
Nevertheless, “The guideline should be helpful for patients,” says John Markman, M.D., associate professor of neurosurgery and Director of the Neuromedicine Pain Management Center at the University of Rochester School of Medicine and Dentistry in Rochester, NY. “You just have to make sure the treatment is tailored to your situation, taking into account any associated diseases you might have,” Dr. Markman says. “So be honest with your doctor about everything that's bothering you.”
SEIZURE DRUG TOPS LIST
The AAN guideline was created by experts who reviewed 79 available scientific studies on therapies for diabetic neuropathy, culled over a four-year period, and then rated the quality of the evidence. (For more on levels of evidence, see “Proof and Consequences” at http://bit.ly/aoknb0.)
Of all the treatments used for diabetic neuropathy and rated by the AAN, the seizure medication pregabalin was the only one found to have “strong evidence” supporting its effectiveness.
Just below pregabalin, in the category with “moderate evidence” supporting their effectiveness, were a host of other treatments. The seizure drugs gabapentin and valproate were in this category, with some evidence that gabapentin works better if taken with the antidepressant venlafaxine. However, the AAN guideline also notes that valproate can cause weight gain, trouble controlling blood sugar levels, and serious birth defects.
The antidepressant drugs amitriptyline, venlafaxine, and duloxetine were also in this category, but the AAN guideline points out that research hasn't determined which works best. Topical drugs with moderate evidence of effectiveness against diabetic nerve pain include capsaicin cream and isosorbide dinitrate spray.
Opioids such as dextromethorphan, morphine sulphate, tramadol, and controlled-release oxycodone are noted in the new AAN guideline for having “moderate evidence” of temporary effectiveness. However, their serious side effects—including rebound headaches in between drug doses and the possibility of opioid dependence—were also highlighted.
Only one non-pharmaceutical therapy, transcutaneous electric nerve stimulation (TENS)—a portable device that sends an electrical current to electrodes attached to the skin—was shown to have moderate evidence supporting its effectiveness.
LESS EFFECTIVE TREATMENTS
Moderate evidence showed that other seizure drugs such as oxcarbazepine, lamotrigine, and lacosamide were not helpful in treating diabetic neuropathy, and that it's too early to determine whether the drug topiramate is helpful. Similarly, there was insufficient evidence to support or refute use of the antidepressants desipramine, imipramine, fluoxetine—along with the combination of nortriptyline with fluphenazine. There is only weak evidence supporting the effectiveness of the lidocaine patch.
Moderate evidence showed that the heart and circulation drugs clonidine, pentoxifylline, and mexiletine are not helpful, and there is not enough evidence to show if vitamins or alpha-lipoic acid do more good than harm. The AAN guideline also states that evidence leans against the effectiveness of magnetic shoe insoles, laser therapy, and Reiki Massage. More research is needed to determine whether electrotherapy and the antidepressant amitriptyline are effective.
Still, says Dr. Markman,“I'd suggest caution with following any guideline without taking into account the particulars of a patient's pain problem.”
“I view a guideline as an evidence-based collection of population statistics,” notes Dr. Chelimsky. “You still see a doctor to treat every case separately.”