Clinical Care/Education/Nutrition/Psychosocial Research ORIGINALDiabetes ARTICLE Care Publish Ahead of Print, published online February 25, 2011 A Comparative Trial to Evaluate Amitriptyline and Duloxetine in Painful Diabetic Neuropathy A randomized, double-blind, cross-over clinical trial 1 2 HARJOT KAUR, MD PINAKI DUTTA, MD, DM literature did not reveal any head-to- 1 3 DEBASISH HOTA, MD, DM DIPIKA BANSAL, MD, DM 2 1 head comparison of duloxetine with ANIL BHANSALI, MD AMITAVA CHAKRABARTI, MD, DM amitriptyline, an established first-line therapy for PDN (1). Thus, the current study was planned to compare the effi- OBJECTIVE— fi To compare the ef cacy and safety of duloxetine and amitriptyline in painful cacy and safety of duloxetine with ami- diabetic neuropathy (PDN). triptyline in PDN. RESEARCH DESIGN AND METHODS—In this randomized, double-blind, cross-over, active-control trial, 58 patients received amitriptyline and duloxetine orally once daily at bed- RESEARCH DESIGN AND time, each for 6 weeks with optional dose uptitration fortnightly. Single-blinded placebo wash- METHODS—Patients of either sex out was given for 2 weeks between the two treatments and a single-blinded placebo run-out with type 2 diabetes, aged between 18 phase of 4 weeks was given at the end of the treatment period. Pain relief was measured by the and 75 years, who were on stable glucose- patient’s global assessment of efficacy, using a visual analog scale (0–100) as a primary end point, lowering medications during the preced- and overall improvement and adverse events were assessed as secondary outcome measures. – , ing month and who had PDN for at least 1 Median pain score reductions of 50%, 25 50%, and 25% were considered good, moderate, month were considered for the study. and mild responses, respectively. Patients who had a pain score of .50%, RESULTS—There was a significant improvement in pain with both treatments compared with as assessed by visual analog scale (VAS), their baseline values (P , 0.001 for both). Good, moderate, and mild pain relief was achieved in were enrolled in the study. Those previ- 55, 24, and 15% of patients, respectively, on amitriptyline and 59, 21, and 9% of patients, ously exposed to medications for PDN, respectively, on duloxetine. There were no significant differences in various other outcome regardless of dose and duration, were measures between the groups. Of the reported adverse events, dry mouth was significantly more considered after 2 weeks of placebo wash- common with amitriptyline than duloxetine (55 vs. 24%; P , 0.01). Although, numerically, fi P out in a single-blind manner. The study more patients preferred duloxetine, overall this was not statistically signi cant (48 vs. 36%; = was initiated after approval by the institu- 0.18). tional ethics committee and was con- CONCLUSIONS—Both duloxetine and amitriptyline demonstrated similar efficacy in PDN. ducted following the principles of the A large, multicentric clinical trial in other populations could possibly demonstrate the superiority Declaration of Helsinki. Written informed of either drug. consent was obtained from each subject prior to enrollment. PDN was confirmed by 1) the pa- tient’s medical history, 2) a diabetic neu- he management of painful diabetic Administration for the treatment of ropathy symptom (DNS) score of .1 neuropathy (PDN) includes inten- PDN. It attenuates persistent pain mech- point (7), 3) a diabetic neuropathy exam- T . 4 sive glycemic control and drugs for anisms, including the central sensitiza- ination (DNE) score of 3points(8), )a pain relief. The American Diabetes Asso- tion and hyperexcitability of the spinal modified neuropathy symptom score ciation recommends amitriptyline, a tri- and supraspinal pain-transmitting path- (NSS) (9,10), and 5) increased thresholds cyclic antidepressant, as the first choice; ways. Duloxetine has been evaluated in on the vibration perception test and however, titration to higher doses is placebo-controlled trials for a variety of monofilament test. Patients were ex- limited by its anticholinergic adverse ef- chronic pain, including PDN (2–6). It cluded if they had any clinically signifi- fects (1). The selective serotonin norepi- not only relieves pain but also improves cant or unstable medical or psychiatric nephrine reuptake inhibitor, duloxetine, functionality and quality of life in patients illnesses. Patients with other causes of is approved by the Food and Drug with PDN. An extensive search of neuropathy; renal dysfunction (serum creatinine .132 mmol/L); liver disease ccccccccccccccccccccccccccccccccccccccccccccccccc (alanine aminotransferase and aspartate From the 1Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chan- aminotransferase more than three time digarh, India; the 2Department of Endocrinology, Postgraduate Institute of Medical Education and Re- 3 times the normal level); epilepsy; psychi- search, Chandigarh, India; and the Department of Pharmacy Practice, National Institute of Pharmaceutical atric illness; uncontrolled hypertension; Education and Research, S.A.S. Nagar, India. Corresponding author: Anil Bhansali, [email protected]. malignancy; substance abuse; those tak- Received 17 September 2010 and accepted 28 January 2011. ing anticonvulsants, antidepressants, lo- DOI: 10.2337/dc10-1793 cal anesthetics, or opioids; those who © 2011 by the American Diabetes Association. Readers may use this article as long as the work is properly were pregnant; lactating women; or those cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/ licenses/by-nc-nd/3.0/ for details. being treated with any investigational care.diabetesjournals.org DIABETES CARE 1 Copyright American Diabetes Association, Inc., 2011 Amitriptyline or duloxetine in PDN drug within the last 30 days were ex- by an independent person unrelated to washout was given and the next sched- cluded from the study. the study. The drug packets were admin- uled drug was started. Patients were not A 14-week, randomized (computer- istered to patients serially according to the allowed any pain medication other than generated randomization of blocks of patient’s reporting sequence. A median up to 3 g per day paracetamol as a rescue four), double-blind, cross-over, active- pain score reduction on the basis of the medication during the trial period, except control with optional dose titration, VAS of .50%, between 25 and 50%, and 24 h prior to assessment. Compliance was equivalence clinical trial was conducted. ,25% were considered as good, moder- assessed by direct questioning and pill All patients underwent an initial 2-week ate, and mild responses, respectively. counting. Success of blinding was as- run-in period in order to achieve a base- Overall improvement in pain intensity of sessed by the accuracy of the physician’s line state (during which the patients were $30 and $50% also was assessed. As- prediction at the end of the study. withdrawn from any existing medication sessments for depression and change in for PDN), followed by 6 weeks of treat- sleep pattern were performed at the be- Statistical analysis ment with each drug and a washout ginning and end of each of the treatments, The sample size calculation was based on period of 2 weeks between the two ther- PGIC was assessed at the end of each the means and SDs observed for pain apies. At the end of 14 weeks, patients treatment period, and patient preference scores in previous trials of duloxetine entered a 4-week run-out phase, during of treatment was carried out fortnightly versus placebo and amitriptyline versus which placebo response was evaluated after beginning the second treatment, placebo in PDN. The efficacy of both in a single-blind manner. whereas all other assessments were per- drugs was estimated to be 70%. To prove Three doses each of amitriptyline (10, formed at each of the 2-weekly follow- that there is no difference in efficacy 25, or 50 mg once daily at bed time) and up visits. The investigator administered between the two treatments, with two- duloxetine (20, 40, of 60 mg once daily at the drug and performed assessment for sided significance levels of 2.5% and bed time) were used in the study. Wock- the efficacy and safety at each visit and power of 80%, a within-subject SD of hardt Limited (Mumbai, India) and Sun was accessible by telephone to all patients 20%, and a maximum-allowable differ- pharmaceutical Industries Limited throughout the study. No additional dose ence of 10%, the total number of patients (Mumbai, India) provided amitriptyline escalation was carried out in the case of to be included was 44. Because of its and duloxetine, respectively, as free sam- appearance of adverse events, lack of ben- cross-over design, with 40% noncompli- ples. Treatment was started with the low- efit with the initial two doses (no benefit ance and loss to follow-up, we decided to est dose of either drug, with fortnightly on patient VAS), patient’s satisfaction include a total of 60 patients in the study. assessments with optional uptitration. with pain relief, the highest dose was The primary and secondary efficacy anal- The primary end point of the study reached, or patient’s noncompliance. Pa- yses were performed on the intention-to- was the reduction in the median pain tients were reminded by telephone calls treat population, defined as patients who score from baseline, as assessed by the for the due visits and also were traced for received at least one dose of randomized patient’s