Neel Mehta

Efficacy of methylnaltrexone for the treatment of opiod-induced constipation: a meta-analysis and systematic review.

ABSTRACT Objective: Constipation is a common adverse effect in patients requiring long-term opioid therapy for pain control. Methylnaltrexone, a quaternary peripheral mu-opioid receptor antagonist, is an effective treatment of opioid induced constipation (OIC) without affecting centrally mediated analgesia. Our objective was to conduct a review and meta-analysis to evaluate the efficacy of methylnaltrexone for treatment of OIC, as well as to provide a clinical discussion regarding newly developed alternatives and provide the current treatment algorithm utilized at our institution. Methods: We performed a systematic review and meta-analysis of randomized control trials using Cochrane Collaboration Databases and MEDLINE from 2007-present. Literature related to methylnaltrexone, opioids, opioid receptors, opioid antagonists, opioid-induced constipation were reviewed. A meta-analysis was completed with the primary outcome of rescue-free bowel movement (RFBM) within four hours of administration. All pooled analyses were based on random-effects models. Results: 1239 patients were analyzed; 599 received methylnaltrexone and 640 received placebo. With a 95% CI calculated, the true risk difference is between 0.267 and 0.385, demonstrating a statistically significant difference in RFBM between treatment and placebo groups (p < 0.0001). Both the 0.15 mg/kg, 0.30 mg/kg doses every other day, and 12 mg/day dose were found to have increased risk of RFBM compared to placebo. Conclusion: Results support the use of methylnaltrexone. Furthermore, the use of methylnaltrexone to induce laxation may decrease use of health care resources, increase work productivity, and improve cost utilization. New treatments have been made available; however, controlled clinical studies are needed to demonstrate long–term efficacy, safety and cost–effectiveness. Possible limitations of this study include the relatively small number of randomized, placebo-controlled trials investigating the efficacy of methylnaltrexone versus placebo. There is also the possibility of publication bias, which may lead to overestimating the efficacy of methylnaltrexone in treating OIC.

A Systematic Review of NMDA Receptor Antagonists for Treatment of Neuropathic Pain in Clinical Practice

Objective: To investigate the efficacy of N-methyl-D-aspartate receptor (NMDAR) antagonists for neuropathic pain (NeuP) and review literature to determine if specific pharmacologic agents provide adequate NeuP relief. Methods: Literature was reviewed on PubMed using a variety of key words for 8 NMDAR antagonists. These key words include: “Ketamine and Neuropathy,” “Ketamine and Neuropathic Pain,” “Methadone and Neuropathy,” “Methadone and Neuropathic Pain,” “Memantine and Neuropathic pain,” “Memantine and Neuropathy,” “Amantadine and Neuropathic Pain,” “Amantadine and Neuropathy,” “Dextromethorphan and Neuropathic Pain,” “Dextromethorphan and Neuropathy,” “Carbamazepine and Neuropathic Pain,” “Carbamazepine and Neuropathy,” “Valproic Acid and Neuropathy,” “Valproic Acid and Neuropathic Pain,” “Phenytoin and Neuropathy,” and “Phenytoin and Neuropathic Pain.” With the results, the papers were reviewed using the PRISMA (Preferred Reporting in Systematic and Meta-Analyses) guideline. Results: A total of 58 randomized controlled trials were reviewed among 8 pharmacologic agents, which are organized by date and alphabetical order. Of the trials for ketamine, 15 showed some benefit for analgesia. Methadone had 3 positive trials, while amantadine and memantine each only had 2 trials showing NeuP analgesic properties. Dextromethorphan and valproic acid both had 4 randomized controlled trials that showed some NeuP treatment benefit while carbamazepine had over 8 trials showing efficacy. Finally, phenytoin only had 1 trial that showed clinical response in treatment. Conclusions: There are a variety of NMDAR antagonist agents that should be considered for treatment of NeuP. Nevertheless, continued and further investigation of the 8 pharmacologic agents is needed to continue to evaluate their efficacy for treatment of NeuP.

Using Chronic Pain Outcomes Data to Improve Outcomes

Standardization of care that is derived from analysis of outcomes data can lead to improvements in quality and efficiency of care. The outcomes data should be validated, standardized, and integrated into ongoing patient care with minimal burden on the patient and health care team. This article describes the organization and workflow of a chronic pain clinic registry designed to collect and analyze patient data for quality improvement and dissemination. Future efforts in using mobile technology and integrating patient-reported outcome data in the electronic health records have the potential to offer new and improved models of comprehensive pain management.

Treatment of Chronic Pain With Various Buprenorphine Formulations: A Systematic Review of Clinical Studies

Clinical studies demonstrate that buprenorphine is a pharmacologic agent that can be used for the treatment of various types of painful conditions. This study investigated the efficacy of 5 different types of buprenorphine formulations in the chronic pain population. The literature was reviewed on PubMed/MEDLINE, EMBASE, Cochrane Database, clinicaltrials.gov, and PROSPERO that dated from inception until June 30, 2017. Using the population, intervention, comparator, and outcomes method, 25 randomized controlled trials were reviewed involving 5 buprenorphine formulations in patients with chronic pain: intravenous buprenorphine, sublingual buprenorphine, sublingual buprenorphine/naloxone, buccal buprenorphine, and transdermal buprenorphine, with comparators consisting of opioid analgesics or placebo. Of the 25 studies reviewed, a total of 14 studies demonstrated clinically significant benefit with buprenorphine in the management of chronic pain: 1 study out of 6 sublingual and intravenous buprenorphine, the only sublingual buprenorphine/naloxone study, 2 out of 3 studies of buccal buprenorphine, and 10 out of 15 studies for transdermal buprenorphine showed significant reduction in pain against a comparator. No serious adverse effects were reported in any of the studies. We conclude that a transdermal buprenorphine formulation is an effective analgesic in patients with chronic pain, while buccal buprenorphine is also a promising formulation based on the limited number of studies.

Assessment of rescue opioid use in patients with post-bunionectomy pain treated with diclofenac potassium liquid-filled capsules

When used in multimodal analgesia for acute pain, nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the requirement for opioids during the perioperative period. To provide more insight into pain treatment during the outpatient period, we examined the use of opioid rescue medication (RM) and described the relationship between pain intensity and RM use in patients with acute pain after bunionectomy. Patients received placebo or 25 mg of a liquid-filled capsule version of the NSAID diclofenac potassium (DPLFC; n=188 patients/group) every 6 hours during the 48-hour inpatient period through the end of outpatient dosing on day 4. Opioid RM (hydrocodone/acetaminophen tablets, 5 mg/500 mg) was available as needed, but taken at least 1 hour post-study medication. Fewer patients taking DPLFC versus placebo requested opioid RM during the inpatient period (4.8%–44.7% versus 25.0%–90.4%) and also during the outpatient period (3.7%–16.0% versus 13.1%–46.4%). Moderate or severe pain after surgery (P=0.0307 and P=0.0002, respectively) or at second dose (P=0.0006 and P=0.0002, respectively) was predictive of RM use. Patients taking RM (placebo/DPLFC) reported more adverse events (RM 55.7%/40.6%; no RM 29.4%/26.0%). Most adverse events in the RM group were opioid-related. In summary, this study shows that DPLFC lowers the requirement for opioids, which is associated with a reduction in the occurrence of treatment side effects, while maintaining adequate analgesia for patients with moderate acute pain in both the outpatient and outpatient periods. Patients with more severe pain are more likely to use RM, but they still use fewer opioids when treated with DPLFC. This suggests that multimodal treatment using DPLFC and an opioid may offer an important clinical benefit in the treatment of acute pain, including in the home environment.

Opiate-Free Pain Therapy Using Carbamazepine-Loaded Microparticles Provides Up to 2 Weeks of Pain Relief in a Neuropathic Pain Model

Opioids remain a mainstay in the treatment of acute and chronic pain, despite numerous and potentially dangerous side effects. There is a great unmet medical need for alternative treatments for patients suffering from pain that do not result in addiction or adverse side effects. Anticonvulsants have been shown to be effective in managing pain, though high systemic levels and subsequent side effects limit their widespread usage. Our goal was to determine if the incorporation of an anticonvulsant, carbamazepine, into a biodegradable microparticle for local sustained perineural release would be an efficacious analgesic following a peripheral injury.

Using electronic health records to characterize prescription patterns: focus on antidepressants in nonpsychiatric outpatient settings

Abstract Objective To characterize nonpsychiatric prescription patterns of antidepressants according to drug labels and evidence assessments (on-label, evidence-based, and off-label) using structured outpatient electronic health record (EHR) data. Methods A retrospective analysis was conducted using deidentified EHR data from an outpatient practice at a New York City-based academic medical center. Structured “medication–diagnosis” pairs for antidepressants from 35 325 patients between January 2010 and December 2015 were compared to the latest drug product labels and evidence assessments. Results Of 140 929 antidepressant prescriptions prescribed by primary care providers (PCPs) and nonpsychiatry specialists, 69% were characterized as “on-label/evidence-based uses.” Depression diagnoses were associated with 67 233 (48%) prescriptions in this study, while pain diagnoses were slightly less common (35%). Manual chart review of “off-label use” prescriptions revealed that on-label/evidence-based diagnoses of depression (39%), anxiety (25%), insomnia (13%), mood disorders (7%), and neuropathic pain (5%) were frequently cited as prescription indication despite lacking ICD-9/10 documentation. Conclusions The results indicate that antidepressants may be prescribed for off-label uses, by PCPs and nonpsychiatry specialists, less frequently than believed. This study also points to the fact that there are a number of off-label uses that are efficacious and widely accepted by expert clinical opinion but have not been included in drug compendia. Despite the fact that diagnosis codes in the outpatient setting are notoriously inaccurate, our approach demonstrates that the correct codes are often documented in a patient’s recent diagnosis history. Examining both structured and unstructured data will help to further validate findings. Routinely collected clinical data in EHRs can serve as an important resource for future studies in investigating prescribing behaviors in outpatient clinics.

Intravenous Conscious Sedation for Routine Fluoroscopically Guided Lumbar Interventions

A healthy 43-year-old man with no significant medical history has been seen in a pain management clinic for radicular symptoms into his right leg that started a month prior to presentation. Pain starts in the right lower back with radiation into the right lateral thigh and posterolateral calf. He does not report any weakness. The patient has tried taking oral anti-inflammatory drugs and has completed 10 sessions of physical therapy without significant relief. He is neurologically intact with full strength and reflexes, and examination reveals a positive straight leg raise on the right. Magnetic resonance imaging shows a right paracentral disk protrusion at the L3/L4 level that is compressing the traversing right L4 nerve root. At this time, a decision is made to offer the patient a transforaminal lumbar epidural steroid injection. On the day of the procedure, the patient’s preprocedural pain score is 4/10 at rest. He mentions in the preprocedure holding area that a friend underwent a similar injection with conscious sedation, and he requests the same. Drs Neel Mehta and Jennifer Zocca will argue that conscious sedation should be offered to this patient. Drs Naum Shaparin and Max Snyder will argue against the use of conscious sedation.

VIP Patients: An Unexpectedly Vulnerable Population

When very important people (VIPs) become patients, they are at risk for receiving substandard care. Obstacles in the way of ideal care for these individuals include challenges with maintaining privacy, the complex attitudes of health-care professionals toward VIP patients, and the expectations of the VIP patient and family. While more research is certainly needed on this topic, health-care professionals and institutions should have a plan in place for treating VIP patients in order to ensure that their care and the care of other patients are not compromised. This plan must attend to patient and provider attitudes and expectations, a complex web of family and caregivers, and the influence of the VIP patient on the health-care system as a whole.