By Brian Hoyle
MONTREAL -- October 21, 2009 -- Taking a combination tablet of tramadol, a leading prescription medication for pain, and acetaminophen is as effective in relieving painful diabetic neuropathy as the gamma-aminobutyric acid analogue gabapentin, according to a multicentre study from Korea presented here at the 20th World Diabetes Congress of the International Diabetes Federation (IDF).
Of people with type 1 or type 2 diabetes, 60% to 70% will develop neuropathy. For some, the consequences, such as loss of sensation or a tingling feeling in the affected region of the body, are a troubling inconvenience. However, neuropathy may produce chronic and debilitating pain. Although gabapentin can provide pain relief, it carries the risk of side effects that range from mild to the potential for compromised breathing and seizures.
Clinical trials have shown that the tramadol/acetaminophen combination is more effective than either drug alone, with a faster onset than given by tramadol and longer-lasting pain relief than provided by acetaminophen. However, less is known about the comparative safety and efficacy of tramadol/acetaminophen versus gabapentin.
On October 20, Jiyuhan Lee, MD, Daegu Catholic University Medical Center, Daegu, Korea, presented the results of the 6-week randomised, open, comparative study conducted at 13 tertiary referral university hospitals throughout Korea. The study involved 139 patients (aged 18-75 years) with painful symmetric diabetic neuropathy. Patients had a mean pain rating of 4 on a scale of 0 (least) to 10 (worst) in the 48 hours before study.
Patients were randomised to receive tramadol/acetaminophen (n = 66) or gabapentin (n = 73). The primary endpoint was reduction in pain intensity. The secondary endpoint, pain relief, was measured with a 6-point scale (from worse pain to complete relief), the Brief Pain Inventory (BPI), a 36-item health survey, subject and investigator perceptions of treatment measured on a Likert scale, average pain intensity for the preceding 24 hours, and diary-recorded observations of sleep disturbance caused by leg pain.
The treatment groups were similar in terms of mean baseline pain intensity (tramadol/acetaminophen, 6.7; gabapentin, 6.3) and age. Similarities were also found in mean pain intensity differences (tramadol/acetaminophen, -3.1; gabapentin, -2.7), mean pain relief score (tramadol/acetaminophen, 2.1; gabapentin, 2.0), survey-reported improvement, and BPI.
Adverse events such as nausea, dizziness, constipation, headache, and heartburn were noted for both tramadol/acetaminophen (50.6%) and gabapentin (36.9%) and were not significantly different. More severe events did not occur.
"The results of this study suggest that tramadol/acetaminophen combination tablets are as effective as gabapentin in the treatment of painful diabetic neuropathy," concluded Dr. Lee.
Whether the combination treatment proves to be a cost-effective alternative to gabapentin remains unclear.
Funding for this study was provided by Janssen Korea.
[Presentation title: Comparison of the Analgesic Efficacy and Safety Between Tramadol/Acetaminophen Combination Tablet (Ultracet) and Gabapentin for the Treatment of Painful Diabetic Neuropathy. Abstract O-0218]
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