Diabetic Neuropathy, Gastropathy Respond to New Treatments

Laurie Barclay, MD

October 02, 2002

Oct. 3, 2002 — Complications from long-standing diabetes may respond to new treatment strategies reported in the October issue of Diabetes Care.

Because diabetic neuropathy can be a painful condition that may be associated with nitric oxide (NO), investigators tested a spray containing isosorbide dinitrate (ISDN), a common NO donor used for heart patients, and found that it reduced overall neuropathic pain and burning with no effect on other symptoms. A letter in the same issue reported on two patients with diabetic gastropathy in whom sildenafil improved gastric emptying and clinical symptoms, suggesting a possible mechanism and new therapy for diabetic gastropathy.

"Considerable evidence implicates impaired NO generation in the pathogenesis of diabetic neuropathic pain," write Kevin C. J. Yuen, MRCP, from Addenbrooke's Hospital in Cambridge, U.K., and colleagues.

In this double-blind, two-period crossover design study, 22 diabetic patients had a two-week run-in period before randomization to ISDN or placebo sprays, then exchanged their treatment for an additional four weeks after a two-week wash-out period. Of the 22 patients, 13 were men, and 20 had type 2 diabetes. Mean age was 63.7 ± 1.8 years, duration of diabetes was 9.1 ± 1.5 years, and duration of painful neuropathy was 2.6 ± 0.4 years. The spray was administered to both feet before bedtime for four weeks.

Compared with placebo, ISDN spray reduced overall neuropathic pain (P=.02) and burning sensation (P=.006) without affecting other sensory modalities such as hot or cold sensation, tingling, numbness, hyperesthesia, or jabbing sensation. After treatment, 11 patients (50%) reported benefit from the ISDN spray and wished to continue this treatment, four (18%) preferred the placebo spray, and seven (32%) were undecided.

"ISDN spray offers an alternative and effective pharmacological option in relieving overall pain and burning sensation in the management of painful diabetic neuropathy," the authors write. "The potential of ISDN spray in alleviating other specific sensory symptoms associated with diabetic peripheral neuropathy merits further study."

Because diabetic gastropathy may involve impairment of gastric nitrergic neurons or of Cajal cells, Alessandro Bianco, MD, and colleagues from Universita Cattolica in Rome, Italy, studied the effect of sildenafil in two women with this disorder, and found that it improved gastric emptying.

"It is conceivable that in diabetic gastropathy, sildenafil could improve gastric emptying by reversing the loss of nitrergic neurotransmitters," they write. "It would be interesting to further evaluate phosphodiesterase-type 5 inhibitors as a new therapeutic approach to diabetic gastroparesis."

Diabetes Care. 2002;25(10):1699-1703, 1888-1889

Reviewed by Gary D. Vogin, MD


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