Clinical correlates and outcomes associated with pregabalin use among people prescribed opioids for chronic non-cancer pain: A five-year prospective cohort study

Experiences of misuse and symptoms of dependence among people who use gabapentinoids: a qualitative systematic review protocol

INTRODUCTION

Gabapentinoids are among the most widely prescribed pain medications. However, there is growing evidence to suggest that gabapentinoids may be associated with dependence and misuse. The aim of this systematic review is to synthesise the qualitative literature on gabapentinoid misuse and symptoms of dependence. The findings of this study will inform efforts to mitigate emerging harms.

METHODS AND ANALYSIS

A systematic review of qualitative research will explore lived experiences of misuse and symptoms of dependence among people who use gabapentinoids. Six databases (MEDLINE, Scopus, Web of Science, CINAHL, EMBASE and PsycINFO) and grey literature sources will be searched from inception to May 2023. Qualitative studies that include people with lived experiences of gabapentinoid misuse and symptoms of gabapentinoid dependence will be included. Reference lists of included studies will also be screened for additional studies. The methodological quality of included studies will be appraised using the Critical Appraisal Skills Programme qualitative checklist, and higher quality studies will be prioritised in the thematic synthesis. The GRADE-CERQual approach will be used to assess confidence in the overall findings of the review.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review. The findings of this review will be disseminated in peer-reviewed journals, at conferences and on social media.

PROSPERO REGISTRATION NUMBER

CRD42023401832.

Predictors of persistent opioid use in non-cancer older adults: a retrospective cohort study

BACKGROUND

Long-term opioid use and associated adverse outcomes have increased dramatically in recent years. Limited research is available on long-term opioid use in older adults.

OBJECTIVE

We aimed to determine the incidence and predictors of long-term or persistent opioid use (POU) amongst opioid-naïve older adults without a cancer diagnosis.

METHODS

This was a retrospective cohort study using five national administrative healthcare databases in New Zealand. We included all opioid-naïve older adults (≥65 years) who were initiated on opioid therapy between January 2013 and June 2018. The outcome of interest was POU, defined as having continuously filled ≥1 opioid prescription within 91-180 days after the index opioid prescription. Multivariable logistic regression was used to examine the predictors of POU.

RESULTS

The final sample included 268,857 opioid-naïve older adults; of these, 5,849(2.2%) developed POU. Several predictors of POU were identified. The use of fentanyl (adjusted odds ratio (AOR) = 3.61; 95% confidence interval (CI) 2.63-4.95), slow-release opioids (AOR = 3.02; 95%CI 2.78-3.29), strong opioids (AOR = 2.03; 95%CI 1.55-2.65), Charlson Comorbidity Score ≥ 3 (AOR = 2.09; 95% CI 1.78-2.46), history of substance abuse (AOR = 1.52; 95%CI 1.35-1.72), living in most socioeconomically deprived areas (AOR = 1.40; 95%CI 1.27-1.54), and anti-epileptics (AOR = 2.07; 95%CI 1.89-2.26), non-opioid analgesics (AOR = 2.05; 95%CI 1.89-2.21), antipsychotics (AOR = 1.96; 95%CI 1.78-2.17) or antidepressants (AOR = 1.50; 95%CI 1.41-1.59) medication use were the strongest predictors of POU.

CONCLUSION

A significant proportion of patients developed POU, and several factors were associated with POU. The findings will enable healthcare providers and policymakers to target early interventions to prevent POU and related adverse events.

Changes in opioid and other analgesic prescribing following voluntary and mandatory prescription drug monitoring program implementation: A time series analysis of early outcomes

BACKGROUND

Australian prescription drug monitoring programs (PDMPs) provide information about a patient's recent medication history for controlled drugs at the point of prescribing and dispensing. Despite their increasing use, the evidence for PDMPs is mixed, and is almost exclusively from the United States. This study examined the impact of PDMP implementation on opioid prescribing among general practitioners in Victoria, Australia.

METHOD

We examined data on analgesic prescribing using electronic records of 464 medical practices in the Australian state of Victoria between 01/04/2017 and 31/12/ 2020. We used interrupted time series analyses, to examine immediate and longer-term trends in medication prescribing following voluntary (from April 2019) and mandatory PDMP implementation (from April 2020). We examined changes in three outcomes (i) 'high' opioid dose (50-100mg oral morphine equivalent daily dose (OMEDD) and over 100mg (OMEDD) prescribing (ii) prescribing of high-risk medication combinations (opioids with either benzodiazepines or pregabalin), and (iii) initiation of non-controlled pain medications (tricyclic antidepressants, pregabalin and tramadol).

RESULTS

We found no effect of voluntary or mandatory PDMP implementation on 'high-dose' opioid prescribing with reductions only seen in those prescribed <20mg OMEDD (i.e., the lowest dose category). Co-prescribing of opioids with benzodiazepines (additional 11.87 [95%CI 2.04 to 21.67] patients/10,000 and pregabalin (additional 3.54 [95% CI 0.82 to 6.26] patients/10,000 increased following mandatory PDMP implementation among those prescribed opioids. In contrast to trends of reduced initiation prior to PDMP implementation, we found increased new initiation of non-monitored medications following PDMP implementation (e.g., an immediate increase of 2.32 [95%CI 0.02 to 4.54], patients/10,000 received pregabalin and 3.06 [95%CI 0.54 to 5.5] patients/10,000 received tricyclic antidepressants after mandatory PDMP implementation), and increased tramadol initiation during the voluntary PDMP period (an increase of 11.26 [95%CI: 5.84, 16.67] patients /10,000).

CONCLUSION

PDMP implementation did not appear to reduce prescribing of high opioid doses or high-risk combinations. Increased initiation of tricyclic antidepressants, pregabalin and tramadol may indicate a possible unintended effect.

Changes of Intestinal Flora and Its Relationship with Nutritional Status for Patients with Cancer Pain

Objective. To study the changes in the intestinal flora and its relationship with nutritional status for patients with cancer pain. Methods. A prospective research method was adopted. One hundred twenty cancer patients with cancer pain were selected as the research objects, who were treated in our hospital from June 2019 to June 2020, and 120 cancer patients without cancer pain were selected as the control group, who were treated in the same period. The differences of the intestinal flora and nutritional status of patients with different severity between the observation group and the control group were compared to analyze the changes of intestinal flora in patients with cancer pain and its correlation with nutritional status. Results. Hemoglobin (HB) ( $t=17.141$ , $p\le 0.001$ ), albumin (ALB) ( $t=27.654$ , $p\le 0.001$ ), prealbumin (PAB) ( $t=96.192$ , $p\le 0.001$ ), and total protein (TP) ( $t=18.781$ , $p\le 0.001$ ) in the observation group were significantly lower than those in the control group. There were statistically significant differences in HB ( $f=13.569$ , $p\le 0.001$ ), ALB ( $f=22.229$ , $p\le 0.001$ ), PAB ( $f=19.521$ , $p\le 0.001$ ), and TP ( $f=21.451$ , $p\le 0.001$ ) among patients with cancer pain of different severity. Through these two comparisons, their nutritional indicators showed a significant downward trend with the increase in the severity for cancer pain patients; the levels of Lactobacillus ( $t=2.124$ , $p=0.035$ ), Bifidobacterium ( $t=4.823$ , $p\le 0.001$ ), Enterococcus ( $t=3.578$ , $p\le 0.001$ ), and Eubacterium ( $t=2.394$ , $p=0.017$ ) in the observation group were significantly lower than those in the control group. There were statistically significant differences in the levels of Lactobacillus ( $f=20.643$ , $p\le 0.001$ ), Bifidobacterium ( $f=19.129$ , $p\le 0.001$ ), Enterococcus ( $f=17.408$ , $p\le 0.001$ ), and Eubacterium ( $f=22.343$ , $p\le 0.001$ ) among patients with cancer pain of different severity. After pairwise comparison, their beneficial intestinal bacteria were significantly lower than those in the control group with the increase in pain in cancer pain patients. Nitric oxide (NO) ( $t=8.418$ , $p\le 0.001$ ), galectin-3 ( $t=14.043$ , $p\le 0.001$ ), occludin (OCLN) ( $t=47.308$ , $p\le 0.001$ ), galectin-1 ( $t=15.298$ , $p\le 0.001$ ), zonula occludens protein 1 (ZO-1) ( $t=23.093$ , $p\le 0.001$ ), and cingulin ( $t=340.198$ , $p\le 0.001$ ) in the observation group were significantly lower than those in the control group. There were statistically significant differences in NO, galectin-3, OCLN, galectin-1, ZO-1, and cingulin for patients with cancer pain of different severity. By comparison, the NO, galectin-3, OCLN, galectin-1, ZO-1, and cingulin of the patients showed a significant downward trend with the aggravation of cancer pain symptoms. Through correlation analysis, the nutritional indicators of patients were positively correlated with intestinal microorganisms and intestinal barrier function. Conclusion. There was a significant correlation between the changes in intestinal flora and nutritional status for patients with cancer pain, which could be used as an important basis for improving the treatment of cancer pain.

Use of pharmacological and nonpharmacological treatments for chronic noncancer pain among people using opioids: a longitudinal cohort study

ABSTRACT

Although multimodal management of chronic noncancer pain (CNCP) is recommended, long-term treatment utilization patterns among people using opioids are not well known. The Pain and Opioids IN Treatment study recruited Australian adults receiving opioids for CNCP for more than 6 weeks from community pharmacies. Pharmacological (opioid and nonopioid analgesics and psychotropic medicines) and nonpharmacological (physical, mental health, and specialized) treatments used in the previous 12 months and 30 days were collected annually over 4 years (2015-2018). Associations were explored between 30-day treatment use and sociodemographic characteristics and pain measures. Overall, 1334 participants completed at least one annual follow-up. The median pain severity (5.0, interquartile range [IQR] 3.8 to 6.3) and pain interference scores (5.7, IQR 3.9-7.3) indicated moderate pain throughout the study period, despite most participants reporting the use of nonopioid pharmacological (12 month: 97.6% and 30 day: 96.8%) and nonpharmacological treatments (12 month: 91.8% and 30 day: 66.1%). Some treatment use was inconsistent with guidelines: ongoing nonsteroidal anti-inflammatory drugs and sedative-hypnotic use were common, whereas fewer people engaged with pain management programs (12 month: 22.3%). Private health insurance was associated with using physical (adjusted odds ratio 1.61, 99.5% confidence intervals 1.15-2.24) and specialized nonpharmacological treatments (adjusted odds ratio 1.47, 99.5% confidence intervals 1.14-1.91). This study demonstrates that many Australians taking opioids long-term for CNCP also use nonopioid pharmacological and nonpharmacological treatments. The use of pharmacological treatments including nonsteroidal anti-inflammatory drugs, psychotropic medicines, and gabapentinoids, outside guidelines, warrants review. Furthermore, despite Australia's universal healthcare scheme subsidising some nonpharmacological treatments, overall use of these treatments was associated with having private health insurance, highlighting a need for more equitable service provision.

Trajectories of pregabalin use and their association with longitudinal changes in opioid and benzodiazepine use

ABSTRACT

Concomitant use of pregabalin with opioids and/or benzodiazepines is common, despite the increased risks. However, clinical trials suggest pregabalin can have an opioid-sparing effect when treating acute postoperative pain. We explored how opioid and benzodiazepine use changed over time in people initiating pregabalin, using dispensing claims data for a 10% sample of Australians (2013-19). Among 142,776 people initiating pregabalin (median age = 61 years, 57% female), we used group-based trajectory modelling to identify 6 pregabalin dose trajectories in the first year postinitiation. Two trajectories involved discontinuation: after one dispensing (49%), and after 6 months of treatment (14%). Four trajectories involved persistent use with variable estimated median daily doses of 39 mg (16%), 127 mg (14%), 276 mg (5%), and 541 mg (2%). We quantified opioid and benzodiazepine use in the year before and after pregabalin initiation using generalised linear models. Over the study period, 71% were dispensed opioids and 34% benzodiazepines, with people on the highest pregabalin dose having highest rates of use. Opioid use increased postpregabalin initiation. Among people using both opioids and pregabalin, the geometric mean daily dose in oral morphine equivalents increased after pregabalin initiation in all trajectories, ranging from +5.9% (99% confidence interval 4.8%-7.0%) to +39.8% (99% confidence interval 38.3%-41.5%) in people on the highest daily pregabalin dose. Among people using both pregabalin and benzodiazepines, the dose remained constant over time for people in all trajectories. Notwithstanding its reputation as opioid-sparing, in this outpatient setting, we observed that people using opioids tended to use higher opioid daily doses after pregabalin initiation, especially those on high pregabalin doses.

Risk Prescriptions of Strong Opioids in the Treatment of Chronic Non-Cancer Pain by Primary Care Physicians in Catalonia: Opicat Padris Project

The prescription of strong opioids (SO) for chronic non-cancer pain (CNCP) is steadily increasing. This entails a high risk of adverse effects, a risk that increases with the concomitant prescription of SO with central nervous system depressant drugs and with the use of SO for non-recommended indications. In order to examine this concomitant risk prescription, we designed a descriptive, longitudinal, retrospective population-based study. Patients aged ≥15 years with a continued SO prescription for ≥3 months during 2013-2017 for CNCP were included. Of these, patients who had received concomitant prescriptions of SO and risk drugs (gabapentinoids, benzodiazepines and antidepressants) and those who had received immediate-release fentanyl (IRF) were selected. The study included 22,691 patients; 20,354 (89.7%) patients received concomitant risk prescriptions. Men and subjects with a higher socioeconomic status received fewer concomitant risk prescriptions. Benzodiazepines or Z-drugs were prescribed concomitantly with SO in 15,883 (70%) patients, antidepressants in 14,932 (65%) and gabapentinoids in 11,267 (49%), while 483 (21.32%) patients received IRF (2266 prescriptions in total) without a baseline SO. In conclusion, our study shows that a high percentage of patients prescribed SO for CNCP received concomitant prescriptions with known risks, as well as IRF for unauthorized indications.

The effect of pregabalin on postdural puncture headache among patients undergoing elective cesarean section: A randomized controlled trial

INTRODUCTION

Post-dural puncture headache (PDPH) is one of the most common problems of cesarean section. The present study aimed to evaluate the effect of pregabalin on PDPH among patients undergoing elective cesarean section.

MATERIALS AND METHODS

This double-blind clinical trial was performed on 136 patients undergoing elective cesarean section referred to Shahid Motahari Teaching Hospital in Urmia in northwestern Iran from February 1 to December 20, 2020. Patients were selected by convenience sampling method and randomly divided into two groups of intervention and control (N = 68 people each group). The presence of PDPH and its severity were recorded in the checklist based on the VAS, and conventional treatments were prescribed in the case of occurrence of the PDPH. The PDPH severity was also assessed by the patient using the 10-cm Visual Analog Scale (VAS).

RESULTS

The mean age of participants was 27.82 years. A total of 29 people suffered from hypotension. Regarding pain severity, the mean pain score in the intervention group was significantly lower than the control group (p = 0.01). Results also showed that the frequency of PDPH in the intervention group was significantly lower than the placebo group (4.4% vs. 11.8%; p = 0.019). There was no significant difference between intervention and control groups in terms of demographic characteristics (p > 0.05).

CONCLUSION

Results of the present study showed the use of oral pregabalin at night before spinal anesthesia in patients undergoing elective cesarean(C-) section had a preventive effect on the severity and incidence of PDPH.

Non-medical Use of Prescription Gabapentinoids (Gabapentin and Pregabalin) in Five European Countries

Background: Non-medical use (NMU) of prescription GABA analogs (pregabalin and gabapentin) has been reported especially in opiate dependent persons. However, by now the prevalence of NMU of gabapentinoids in the general population has not been sufficiently evaluated. The aim of this research paper is to determine the prevalence of prescription GABA analog NMU and associated demographics in five European countries with special detail of Spain. Methods: The RADARS Survey of Non-Medical Use of Prescription Drugs Program (NMURx) is a harmonized series of contemporaneous cross-sectional surveys of adults conducted in multiple countries. NMURx collects data from the general population in each participating country about NMU of prescription drugs, illicit drugs, and associated demographics. NMU was defined as "using a medication without a doctor's prescription or for any reason other than what was recommended by their doctor." Responses from Spain (4Q2017, n=10,062) were analyzed in detail. Comparative data were available from France, Germany, Italy, and UK. Responses were collected using non-probability quota sampling and post-stratification population weighting was applied to reflect the national distributions of adults, based on age, gender, and census region. Rates of NMU and associated demographics were reported as rate of past 90-day NMU per 100,000 adult population with 95% confidence intervals. Results: Germany (1,197 per 100,000 adult population [95% CI: 1,004.3-1,379.1]) and United Kingdom (1,067 per 100,000 adult population [95% CI: 851.3-1,283.2]) presented the highest prevalence of gabapentinoids NMU. In Spain the prevalence of past 90 days GABA analog NMU was: 344.4, 95% (CI 204.8-484.0), with male predominance. Those who non-medically use GABA analogs had a higher prevalence of lifetime chronic pain, lifetime illicit drug use, and previous substance abuse treatment. In Spain, 20% of respondents who ever have used gabapentinoids, reported a lifetime NMU; the prevalence was higher for pregabalin 624 (6.2%) than for gabapentin 444 (4.4%). The main reasons for use were to self-treat pain and other medical conditions. Conclusions: The risk of NMU of gabapentinoids should not be neglected. Subjects with a history of chronic pain and lifetime substance use disorders had an increased risk of NMU of gabapentinoids.