***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Uncontrolled studies have indicated that topically applied capsaicin may be a safe and effective treatment for postherpetic neuralgia .  In a double-blind study 32 elderly patients with chronic postherpetic neuralgia were treated with either capsaicin cream or its vehicle for a 6-week period . Response to treatment was evaluated by visual analogue scales of pain and of pain relief , together with changes in a categoric pain scale and in a physician 's global evaluation . Significantly greater relief in the capsaicin-treated group compared with vehicle was observed for all efficacy variables . After 6 weeks almost 80 % of capsaicin-treated patients experienced some relief from their pain . Because capsaicin avoids problems with drug interactions and systemic toxicity , we suggest that topical capsaicin be considered for initial management of postherpetic neuralgia & NA ; Twenty patients with post‐herpetic neuralgia ( median duration 28.5 months ) were r and omly allocated to receive transdermal iontophoresis of either vincristine or saline . Although significant improvement in pain by word score and visual analogue scale ( P = 0.05 ) was reported by 6 out of 10 of the vincristine group , none of the patients considered themselves ‘ cured . ’ There was no significant change in the saline group . No adverse haematological or neurological side effects were seen , but skin irritation and painless electrical burns were common in both groups . The dramatic relief of pain in patients with post‐herpetic neuralgia of 3 months or less reported elsewhere was not seen in our group who had pain of a longer duration . This present trial does not confirm the value of vincristine iontophoresis in the treatment of post‐herpetic neuralgia of over 6 months duration BACKGROUND Amitriptyline reduces the pain caused by peripheral-nerve disease , but treatment is often limited by side effects related to the drug 's many pharmacologic actions . Selective agents might be safer and more effective . METHODS We carried out two r and omized , double-blind , crossover studies in patients with painful diabetic neuropathy , comparing  amitriptyline with the relatively selective blocker of norepinephrine reuptake desipramine in 38 patients , and comparing the selective blocker of serotonin reuptake fluoxetine with placebo in 46 patients . Fifty-seven patients were r and omly assigned to a study as well as to the order of treatment , permitting comparison among all three drugs and placebo as the first treatment . The patients rated the degree of pain present each day using verbal descriptors , and they also assessed the extent of pain relief globally at the end of each treatment period . RESULTS After individual dose titration , the mean daily doses of the drugs were as follows : amitriptyline , 105 mg ; desipramine , 111 mg ; and fluoxetine , 40 mg . There was moderate or greater relief of pain in 28 of the 38 patients ( 74 percent ) who received amitriptyline , 23 of the 38 patients ( 61 percent ) who received desipramine , 22 of the 46 patients ( 48 percent ) who received fluoxetine , and 19 of the 46 patients ( 41 percent ) who received placebo . The differences in responses between amitriptyline and desipramine and between fluoxetine and placebo were not statistically significant , but both amitriptyline and desipramine were superior to placebo .  Amitriptyline and desipramine were as effective in patients who were not depressed as in depressed patients , but fluoxetine was effective only in depressed patients . CONCLUSIONS Desipramine relieves pain caused by diabetic neuropathy with efficacy similar to that of amitriptyline , offering an alternative for patients unable to tolerate the latter . Blockade of norepinephrine reuptake is likely to mediate the analgesic effect of these antidepressant drugs in diabetic neuropathy . Fluoxetine , which blocks serotonin uptake , is no more effective than placebo for the relief of pain Serotoninergic pathways are believed to be important in pain mechanisms . Accordingly , we studied the action of zimelidine , a very highly serotoninergic antidepressant , in relieving the pain of post-herpetic neuralgia . Fifteen patients received zimelidine and amitriptyline in that order in an open-label cross-over study . Only one patient with zimelidine  obtained a  good result  , whereas 8 patients on amitriptyline amitriptyline has a pain-relieving action , at least in post-herpetic neuralgia , which is not primarily linked with its serotoninergic effects and which is also independent of its effects on depression & NA ; In a double‐blind multiple‐dose cross‐over study benzydamine 3 % cream was compared with placebo for the treatment of post‐herpetic neuralgia .  Pain relief , pain intensity , sleep , escape analgesic consumption and side effects were assessed by diary methods for the 2 week treatment periods , with 1 week run‐in and 1 week wash‐out . There were no significant differences between the 2 treatments . The implication s of the results for other antiprostagl and in remedies recommended for treatment of post‐herpetic neuralgia are discussed . An important observation with method ological significance for similar studies of chronic conditions was that short treatment periods may produce false positive results . Patients ' expectations are high , and if the first study treatment is ineffective , initial significant benefit may be noted when crossing over to the next treatment ; this may not last longer than 1 week . Cross‐over studies in which neither treatment is effective may , therefore , produce erroneous results if treatment periods are shorter than 2 weeks A large double-blind , vehicle-controlled study of 143 patients with chronic postherpetic neuralgia ( PHN ) was performed to evaluate the degree of efficacy of topically applied capsaicin 0.075 % cream . In addition , the safety and efficacy of long-term application of topical capsaicin in PHN was assessed by following patients in an open-label study for up to 2 years . In the double-blind phase , 143 patients with PHN of 6 months ' duration or longer were enrolled . Since epidemiologic studies of patients who receive no treatment have shown that only 10 % to 25 % of those with PHN after 1 month will still have pain at 1 year , two separate efficacy analyses were performed : one with all evaluable patients ( n = 131 ) and the other with 93 patients whose PHN lasted for longer than 12 months prior to study startup . All efficacy variables , including the physician 's global evaluation of reduction in PHN pain , changes in pain severity on the categoric scale , visual analogue scale for pain severity , visual analogue scale for pain relief , and functional capacity scale , showed significant improvement at nearly all time points throughout the study for both patient groups , based on duration of PHN pain . In contrast , the group receiving vehicle cream remained essentially unchanged . Data from the long-term , open-label phase ( up to 2 years , n = 77 ) , which immediately followed the 6-week blinded phase , showed that the clinical benefit in patients treated for a short ( 6-week ) period with topical capsaicin could be maintained or amplified in most patients ( 86 % ) during prolonged therapy . There were no serious adverse effects observed or reported throughout the trial ; in fact , the only side effect associated with capsaicin treatment was the burning or stinging at local sites of application ( in 9 % of patients ) during exposures of up to 2 years ( long-term phase ) . On the basis of these data , we conclude that capsaicin 0.075 % cream is a safe and effective treatment for the pain of postherpetic neuralgia and should be considered for initial management of patients with this condition Desipramine has the least anticholinergic and sedative effects of the first generation tricyclic antidepressant agents , but its pain-relieving potential has received little study . Other antidepressant agents -- notably amitriptyline -- are known to ameliorate postherpetic neuralgia , but those agents are often toxic . In a r and omized double-blind crossover design , we gave 26 postherpetic neuralgia patients 6 weeks of treatment with desipramine ( mean dose , 167 mg/day ) and placebo .  Nineteen patients completed both treatments ; 12 reported at least moderate relief with desipramine and two reported relief with placebo .  Pain relief with desipramine was statistically significant from weeks 3 to 6 . Psychiatric interview at entry into the study produced a diagnosis of depression for 4 patients ; pain relief was similar in depressed and nondepressed patients and was statistically significant in the nondepressed group alone . We conclude that desipramine administration relieves postherpetic neuralgia and that pain relief is not mediated by mood elevation . Blockade of norepinephrine reuptake , an action shared by desipramine , amitriptyline , and other antidepressant agents that have relieved neuropathic pain , may be involved in relief of postherpetic neuralgia In a retrospective survey , 487 research projects approved by the Central Oxford Research Ethics Committee between 1984 and 1987 , were studied for evidence of publication bias . As of May , 1990 , 285 of the studies had been analysed by the investigators , and 52 % of these had been published . Studies with statistically significant results were more likely to be published than those finding no difference between the study groups ( adjusted odds ratio [ OR ] 2.32 ; 95 % confidence interval [ Cl ] 1.25 - 4.28 ) . Studies with significant results were also more likely to lead to a greater number of publications and presentations and to be published in journals with a high citation impact factor . An increased likelihood of publication was also associated with a high rating by the investigator of the importance of the study results , and with increasing sample size . The tendency towards publication bias was greater with observational and laboratory-based experimental studies ( OR = 3.79 ; 95 % Cl = 1.47 - 9.76 ) than with r and omised clinical trials ( OR = 0.84 ; 95 % Cl = 0.34 - 2.09 ) . We have confirmed the presence of publication bias in a cohort of clinical research studies . These findings suggest that conclusions based only on a review of published data should be interpreted cautiously , especially for observational studies . Improved strategies are needed to identify the results of unpublished as well as published studies In a double-blind , r and omized , crossover study , 58 patients with postherpetic neuralgia received 6-week courses of amitriptyline , 12.5 to 150 mg/d ; lorazepam , 0.5 to 6 mg/d ; or lactose placebo . Doses were titrated to the maximum level tolerated . Patients rated pain in a diary , using lists of verbal descriptors . Forty-seven percent of patients reported moderate or greater relief with  amitriptyline  , 16 % with placebo , and 15 % with lorazepam .  Mean amitriptyline  dose was 65 mg/d . Greater relief was associated with higher amitriptyline doses , up to the maxiumum dose of 150 mg/d , and with higher serum tricyclic levels . Lorazepam did not relieve pain and was associated with severe depressive reactions in four patients Twenty-one patients with postherpetic neuralgia of two- to 84-months duration participated in a double-blind , placebo-controlled study of oral acyclovir .  Pain perception was assessed with the Melzack Pain Question naire at baseline and at two-to six-week intervals during the ensuing six months . Clinical ly significant pain reduction occurred in eight patients : four received acyclovir , and four received a placebo . Several treatment strategies have been advocated for relief of postherpetic neuralgia . Results of the present study demonstrate the need for a double-blind , placebo-controlled paradigm to substantiate the efficacy of new clinical approaches . The same caveat applies to the more common syndromes encountered in psychiatric practice Abstract A single blind r and omised controlled study of auricular and body acupuncture compared with placebo ( mock transcutaneous nerve stimulation ) was performed in 62 patients with post‐herpetic neuralgia . There was no difference in the amount of pain relief recorded in the two groups during or after treatment ; 7 patients in the placebo group and 7 patients in the acupuncture group experienced significant improvement in their pain at the end of treatment . This suggests that acupuncture is of little value as an analgesic therapy for post‐herpetic neuralgia . However the study method and the use of a mock transcutaneous nerve stimulator as a placebo may be of value when assessing the effects of acupuncture in other conditions Two hundred and eight patients with post-herpetic neuralgia ( PHN ) were assessed in a prospect i ve , longitudinal study design ed to evaluate demography , clinical features , treatment results and long-term status . PHN affected both sexes equally increasing in frequency and severity with age . There was a predilection for involvement of the ophthalmic division of the trigeminal nerve and for mid-thoracic dermatomes . The pain descriptors chosen reflected both steady and brief paroxysmal components in most patients . Scarring , sensory loss and the exaggerated sensations of hyperesthesia , dysesthesia and allodynia were common findings . Hyperalgesia and hyperpathia were less common . From these open-label , uncontrolled data , antidepressants ( amitriptyline and nortriptyline ) appeared useful in about 60 % of patients . Topical capsaicin seemed to be a promising new approach . A variety of other pharmacological agents and treatment approaches were less successful . Many patients with PHN even of long st and ing continued to improve with time Long-term beta blockade for perhaps a year or so following discharge after an MI is now of proven value , and for many such patients mortality reductions of about 25 % can be achieved . No important differences are clearly apparent 
    Output:
    
Based on evidence from r and omized trials , tricyclic anti-depressants appear to be the only agents of proven benefit for established postherpetic neuralgia