Medicinal Plants for the Treatment of Neuropathic Pain: A Review of Randomized Controlled Trials

Neuropathic pain is a disabling condition caused by various diseases and can profoundly impact the quality of life. Unfortunately, current treatments often do not produce complete amelioration and can be associated with potential side effects. Recently, herbal drugs have garnered more attention as an alternative or a complementary treatment. In this article, we summarized the results of randomized clinical trials to evaluate the effects of various phytomedicines on neuropathic pain. In addition, we discussed their main bioactive components and potential mechanisms of action to provide a better view of the application of herbal drugs for treating neuropathic pain.

Effectiveness of Nonpharmacologic Interventions for Chemotherapy-Induced Peripheral Neuropathy in Patients With Breast Cancer: A Systematic Review and Network Meta-analysis

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse effect in patients with breast cancer (BC) during treatment. Patients experiencing CIPN develop neuropathic symptoms, which could lead to the modification or discontinuation of chemotherapy. Nonpharmacological interventions can be simple and safe, but evidence of their effectiveness in patients with BC experiencing CIPN is currently insufficient.

OBJECTIVE

To compare and rank the effectiveness of nonpharmacologic interventions for CIPN in patients with BC.

METHODS

We conducted a systematic search of randomized controlled trials registered from database inception until October 2022 in 7 databases. We assessed studies that met the inclusion and exclusion criteria and evaluated the risk of bias. Network meta-analysis was conducted using Stata SE 17.0 (StataCorp, College Station, Texas).

RESULTS

A total of 13 studies involving 9 nonpharmacologic interventions and comprising 571 participants were included. The results of the network meta-analysis showed that cryotherapy (standard mean difference, -1.22; 95% confidence interval, -2.26 to -0.17) exerted significant effects versus usual care. Cryotherapy (surface under the cumulative ranking area [SUCRA]: 0.74) was associated with the highest likelihood of effectively alleviating CIPN in patients with BC, followed by exercise (SUCRA: 0.62) and self-acupressure (SUCRA: 0.59).

CONCLUSIONS

Cryotherapy was the most effective nonpharmacologic intervention for alleviating CIPN in patients with BC. Large-scale studies are required to verify the present findings.

IMPLICATIONS FOR PRACTICE

This study provides evidence regarding the effectiveness of nonpharmacologic interventions for CIPN. Physicians and nurses could incorporate cryotherapy into clinical practice to alleviate CIPN in patients with BC.

Prevention and Treatment of Chemotherapy-Induced Peripheral Neuropathy (CIPN) with Non-Pharmacological Interventions: Clinical Recommendations from a Systematic Scoping Review and an Expert Consensus Process

Background: Most individuals affected by cancer who are treated with certain chemotherapies suffer of CIPN. Therefore, there is a high patient and provider interest in complementary non-pharmacological therapies, but its evidence base has not yet been clearly pointed out in the context of CIPN. Methods: The results of a scoping review overviewing the published clinical evidence on the application of complementary therapies for improving the complex CIPN symptomatology are synthesized with the recommendations of an expert consensus process aiming to draw attention to supportive strategies for CIPN. The scoping review, registered at PROSPERO 2020 (CRD 42020165851), followed the PRISMA-ScR and JBI guidelines. Relevant studies published in Pubmed/MEDLINE, PsycINFO, PEDro, Cochrane CENTRAL, and CINAHL between 2000 and 2021 were included. CASP was used to evaluate the methodologic quality of the studies. Results: Seventy-five studies with mixed study quality met the inclusion criteria. Manipulative therapies (including massage, reflexology, therapeutic touch), rhythmical embrocations, movement and mind-body therapies, acupuncture/acupressure, and TENS/Scrambler therapy were the most frequently analyzed in research and may be effective treatment options for CIPN. The expert panel approved 17 supportive interventions, most of them were phytotherapeutic interventions including external applications and cryotherapy, hydrotherapy, and tactile stimulation. More than two-thirds of the consented interventions were rated with moderate to high perceived clinical effectiveness in therapeutic use. Conclusions: The evidence of both the review and the expert panel supports a variety of complementary procedures regarding the supportive treatment of CIPN; however, the application on patients should be individually weighed in each case. Based on this meta-synthesis, interprofessional healthcare teams may open up a dialogue with patients interested in non-pharmacological treatment options to tailor complementary counselling and treatments to their needs.

Treatment for chemotherapy-induced peripheral neuropathy: A systematic review of randomized control trials

Purpose: Treatment of chemotherapy-induced peripheral neuropathy (CIPN) is challenging for clinicians, and many clinical trials and meta-analyses on CIPN are controversial. There are also few comparisons of the efficacy among drugs used to treat CIPN. Therefore, this systematic review aimed to study the efficacy of drugs in treating CIPN using existing randomized controlled trials. Methods: Electronic databases were searched for randomized controlled trials (RCTs) involving any pharmaceutical intervention and/or combination therapy of treating CIPN. Results: Seventeen RCTs investigating 16 drug categories, duloxetine, pregabalin, crocin, tetrodotoxin, venlafaxine, monosialotetrahexosyl ganglioside (GM1), lamotrigine, KA (ketamine and amitriptyline) cream, nortriptyline, amitriptyline, topical Citrullus colocynthis (bitter apple) oil, BAK (baclofen, amitriptyline hydrochloride, and ketamine) pluronic lecithin organogel, gabapentin, and acetyl l-carnitine (ALC), in the treatment of CIPN were retrieved. Many of the included RCTs consisted of small sample sizes and short follow-up periods. It was difficult to quantify due to the highly variable nature of outcome indicators. Conclusion: Duloxetine, venlafaxine, pregabalin, crocin, tetrodotoxin, and monosialotetrahexosyl ganglioside exhibited some beneficial effects in treating CIPN. Duloxetine, GM1, and crocin showed moderate benefits based on the evidence review, while lamotrigine, KA cream, nortriptyline, amitriptyline, and topical Citrullus colocynthis (bitter apple) oil were not beneficial. Further studies were necessary to confirm the efficacy of gabapentin in the treatment of CIPN because of the controversy of efficacy of gabapentin. Furthermore, BAK topicalcompound analgesic gel only had a tendency to improve the CIPN symptoms, but the difference was not statistically significant. ALC might result in worsening CIPN. Most studies were not of good quality because of small sample sizes. Therefore, standardized randomized controlled trials with large samples were needed to critically assess the effectiveness of these drugs in treating CIPN in the future.

Dietary Supplements in Chemotherapy-Induced Peripheral Neuropathy: A New Hope?

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the main and most prevalent side effects of chemotherapy, significantly affecting the quality of life of patients and the course of chemotherapeutic treatment. Nevertheless, despite its prevalence, the management of the CIPN is considered particularly challenging, with this condition often being perceived as very difficult or even impossible to prevent with currently available agents. Therefore, it is imperative to find better options for patients diagnosed with this condition. While the search for the new agents must continue, another opportunity should be taken into consideration-repurposing of the already known medications. As proposed, acetyl-L-carnitine, vitamins (group B and E), extracts of medical plants, including goshajinkigan, curcumin and others, unsaturated fatty acids, as well as the diet composed of so-called "sirtuin-activating foods", could change the typical way of treatment of CIPN, improve the quality of life of patients and maintain the continuity of chemotherapy. This review summarizes currently available data regarding mentioned above agents and evaluates the rationale behind future research focused on their efficacy in CIPN.

Omega-3 Fatty Acids Supplementation Improve Nutritional Status and Inflammatory Response in Patients With Lung Cancer: A Randomized Clinical Trial

Background and Aims: Clinical studies have reported positive results with omega-3 supplements in patients with cancer. This study aimed to evaluate the efficacy of omega-3 fatty acid supplementation in improving the nutritional status and inflammatory markers of patients with lung cancer.

Methods: In a randomized, double-blind, parallel design trial, 60 patients with lung cancer at nutritional status/risk based on the Nutrition Risk Screening 2002 were randomized to be allocated to two study groups, receiving omega-3 fatty acid supplements [eicosapentaenoic acid (EPA) 1.6 g and docosahexaenoic acid (DHA) 0.8 g] or placebo for 12 weeks. Anthropometric measurements [weight, body mass index (BMI), the circumference of the upper arm, and skinfold thickness of triceps], nutrition-based laboratory indices (hemoglobin, albumin, triglyceride, and cholesterol), and inflammatory markers [C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6)] were measured before and after the intervention as study outcomes.

Results: No significant difference between the two study groups was observed regarding basic characteristics and study outcomes. Compared with placebo group, omega-3 fatty acid supplementation group showed significant higher weight (66.71 ± 9.17 vs. 61.33 ± 8.03, p = 0.021), albumin (4.74 ± 0.80 vs. 4.21 ± 0.77, p = 0.013), and triglyceride (130.90 ± 25.17 vs. 119.07 ± 14.44, p = 0.032). Inflammatory markers were significantly reduced in omega-3 group compared to placebo (CRP 1.42 ± 0.63 vs. 3.00 ± 1.05, p = 0.001 and TNF-α 1.92 ± 0.65 vs. 4.24 ± 1.19, p = 0.001). No significant difference was observed between the two study groups regarding changes in BMI, the circumference of the upper arm, skinfold thickness of triceps, triglyceride, cholesterol, and IL-6 (p > 0.05).

Conclusions: Omega-3 fatty acid supplementation can improve nutritional status and suppress the systemic inflammatory response in patients with lung cancer.

Clinical Trial Registration:www.socialscienceregistry.org, identifier: AEARCTR-0007165.

The effects of aromatherapy massage with lavender essential oil on neuropathic pain and quality of life in diabetic patients: A randomized clinical trial

OBJECTIVE

to determine massage lavender essential oil on neuropathic pain and quality of life in diabetic patients.

METHODS

A randomized three-group control trial with the pre-post design was performed from 2019 to 2020 on 75 diabetic neuropathic patients. The patients were randomly allocated into aromatherapy (n = 26), placebo (n = 26), and control (n = 26) groups. Patients in the intervention group used 2.5 cc of 3% lavender oil on their feet as a gentle massage for 10 min every night before bedtime for a month. Data collected using the Visual analog scale (VAS), Douleur Neuropathic 4 (DN4) and Quality of Life Questionnaire (SF36).

RESULTS

The mean difference of pain scores in short-term and long-term in the aromatherapy group was significantly reduced compared to the placebo and control groups (P < 0.001). In addition, after four weeks, a significant increase was found in the QoL domains in the aromatherapy group (P < 0.001).

CONCLUSION

Aromatherapy massage with lavender oil helped reduce neuropathic pain two to four weeks after the intervention and improved the patients' QoL without causing any side effects. Thus, nurses are recommended to use it as a complementary method to reduce neuropathic pain and improve patients' QoL.

Topical Costus sp. Preparation as Palliative Care for Chemotherapy-Induced Peripheral Neuropathy of Patients: A Randomized Placebo-Controlled Pilot Trial

Objectives: Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse effect of various anticancer regimens with different sensory-motor abnormalities in patients. The aim of this study was to examine the feasibility of using Costus sp. oil as a palliative treatment in such patients. Design: This was a pilot randomized placebo-controlled double-blind clinical study. Settings/Location: Imam Hossein Hospital, Tehran, Iran. Subjects: Patients 18-80 years of age undergoing chemotherapy treatment recently or during the last 6 months were enrolled after meeting the inclusion criteria. Interventions: The intervention group used Costus sp. as a topical ointment and the placebo group used topical paraffin for 4 weeks. Outcome measures: Feasibility of recruitment, including treatment acceptability (evaluated as number of patients leaving the study early), and compliance (defined as consumption of a minimum 80% of the ointment) with the intervention were assessed. Neuropathic pain change was defined as the secondary outcome, too. Results: Totally, 50 out of 73 participants were identified eligible and were randomly divided into intervention or placebo groups. There was no significant difference between groups in terms of sociodemographic data. At the end of the study, 24% (confidence interval [95% CI]: 9-45) (intervention group) and 12% (95% CI: 2-31) (placebo group) of patients revealed treatment unacceptability. Meanwhile, 12% (95% CI: 2-31) in the intervention group and 28% (95% CI: 12-49) in the placebo group did not show the compliance. Moreover, according to patients' records, pain reduction was higher in the intervention group compared to the placebo group (p = 0.001). Conclusions: This preliminary study showed that topical use of Costus sp. was feasible and acceptable in patients suffering from CIPN.

Quality Evaluation of the Clinical Trials for Natural Products Used in Cancer: An Evidence-Based Literature Review

The amount of data regarding the use of herbs/herbal products in cancer clinical trials at times creates a great challenge for oncologists to prescribe or counsel patients. It urges critical evaluation of the quality of clinical trials. Herein, for the first time, the clinical trials for herbs used in cancer were critically evaluated on the basis of three widely used scales, i.e., Jadad, Delphi, and Cochrane scales. The literature was collected with the help of online databases, journals, libraries, and books using a number of specific keywords as mentioned in detail in forthcoming sections. A total of 73 clinical trials were extracted, evaluated, and scored for 14 herbs, according to the predefined criteria mentioned below. A major deficiency of “non-blinding of clinical trials” was observed. The principal component analysis revealed four components (PC1–PC4) with a total variability of 68.21%, wherein the highest percentage variability was observed for PC1 loaded with “non-blinding of the clinical trials, no concealment of the treatment allocation, non-blindness of the patient and care provider”, which accounted for 30.81% of the total variability. The next major variability of 14.70% was observed for PC2 loaded with “non-randomization of the studies, non-blinding of the outcome assessors, no proper drop-out procedures, and lack of information regarding baseline characteristics for the groups”. Pearson’s correlation further confirmed a similar correlation pattern for the mentioned deficiencies (p = 0.05). An in-house grading scale was developed, showing a very small portion (16.44%), i.e., 12/73 studies with a good quality, whereas the majority (57.54%) of the studies, i.e., 42/73, were found to be of poor quality. The rules and regulations governing the quality of clinical trials needs to be more stringent and updated for the natural products/herbs used in cancer clinical trials.

How to transfer traditional knowledge about medicinal herbs? or TCM plants: a black box for modern oncologists

OBJECTIVE

How could we transfer knowledge about healing plants from other cultures? We analyzed the results of literature search in two exemplary fields-oral mucositis and polyneuropathy.

MATERIALS AND METHODS

In both systematic searches of existing literature, we found 57 studies investigating 68 plants from different traditional cultures (16 Western Medicine, 14 Persian Medicine, 9 Japanese, 10 Chinese, and 8 other sources). We analyzed studies regarding their ingredient plants and reproducibility in relation to the system of origin.

RESULTS

Western and Persian Medicine trials investigate single plants, whereas Japanese and Chinese trials focus on mixtures and decoctions. European folk medicine knows of only 50% of plants used in both Asian cultures. The used ingredients and dosages were reproducible in all analyzed trials except TCM studies.

CONCLUSIONS

Herbal knowledge has been transferred from all folk medicines worldwide. However, Western oncologists should be aware that Traditional Chinese Medicine herbs are still a black box of knowledge for us until today.