Methadone pharmacokinetics in opioid agonist treatment: Influencing factors and clinical implications

BACKGROUND

A considerable inter-individual variability has been reported in the relationship between methadone doses applied and serum concentrations achieved in methadone maintenance treatment. However, the underlying causes for this variability are not fully understood.

OBJECTIVES

We investigated the influence of genetic, pathophysiological and pharmacological factors on serum methadone concentration-to-dose ratio (CDR) and discussed the clinical implications of the findings.

METHODS

We used data from two retrospective laboratory databases and a prospective cohort study to investigate the impact on methadone CDR of hepatic cytochrome P450 enzyme system (CYP) genetic polymorphisms, age, sex, concomitant medication, liver fibrosis and body mass index through linear mixed model analyses.

FINDINGS

A positive association was found between CDR and the homozygous CYP2B6*6 genotype, concurrent treatment with CYP3A4 inhibitors and body mass index. CDR was lower among women and during concomitant use of CYP inducers. CDR was not associated with age or the degree of liver fibrosis in our investigations.

CONCLUSIONS

This research work supports the need for individually tailored dosage considering the various factors that influence methadone CDR. The gained knowledge can contribute to reducing the risks associated with the treatment and optimizing the desired outcomes.

Effect of integrated hepatitis C virus treatment on psychological distress in people with substance use disorders

People with substance use disorders (SUD) have a high prevalence of chronic hepatitis C virus (HCV) infection and mental health disorders. We aimed to assess the impact of integrated HCV treatment on psychological distress measured by Hopkins-symptom-checklist-10 (SCL-10). This multi-center randomized controlled trial evaluated psychological distress as a secondary outcome of integrated HCV treatment (INTRO-HCV trial). From 2017 to 2019, 289 participants were randomly assigned to receive either integrated or standard HCV treatment with direct-acting antiviral therapy. Integrated HCV treatment was delivered in eight decentralized outpatient opioid agonist therapy clinics and two community care centers; standard treatment was delivered in internal medicine outpatient clinics at centralized hospitals. Participants in the integrated treatment arm had a sustained virologic response of 93% compared to 73% for those in standard treatment arm. Psychological distress was assessed using SCL-10 prior to initiation of HCV treatment and 12 weeks after treatment completion. The mean SCL-10 score prior to HCV treatment was 2.2 (standard deviation [SD]: 0.7) for patients receiving integrated HCV treatment and 2.2 (SD: 0.8) for those receiving standard HCV treatment. Twelve weeks after the end of treatment, the mean SCL-10 score change was - 0.1 (- 0.3;0.0) in the integrated compared to the standard arm. Psychological distress did not substantially change during the treatment period and was not significantly different between the treatment arms.

Attention-deficit/hyperactivity disorder (ADHD) symptoms and their relation to diagnosed ADHD, sociodemographic characteristics, and substance use among patients receiving opioid agonist therapy: a Norwegian cohort study

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) symptoms may challenge sufficient treatment of substance use and mental disorders. The literature on the extent of such symptoms among patients receiving opioid agonist therapy (OAT) is scarce. This study examined ADHD symptoms using the ADHD self-report scale (ASRS) and the association between the 'ASRS-memory' and 'ASRS-attention' scores and substance use and sociodemographic characteristics among patients receiving OAT.

METHODS

We used data from assessment visits of a cohort of patients in Norway. In total, 701 patients were included from May 2017 to March 2022. All patients responded at least once to two ASRS questions assessing memory and attention, respectively. Ordinal regression analyses were performed to investigate whether the two obtained scores were associated with age, sex, frequent substance use, injecting use, housing status, and educational attainment at baseline, i.e., the first assessment, and over time. The results are presented as odds ratios (OR) with 95% confidence intervals (CI). Additionally, a subsample of 225 patients completed an extended interview, including the ASRS-screener and collection of registered mental disorder diagnoses from the medical records. Standard cutoffs were used to define the presence of each ASRS symptom or a positive ASRS-screener ('ASRS-positive').

RESULTS

At baseline, 428 (61%) and 307 (53%) patients scored over the cutoffs on the 'ASRS-memory' and 'ASRS-attention,' respectively. Frequent cannabis use was associated with higher 'ASRS-memory' (OR: 1.7, 95% CI: 1.1-2.6) and 'ASRS-attention' (1.7, 1.1-2.5) scores compared with less or no use at baseline, though reduced score on the 'ASRS-memory' over time (0.7, 0.6-1.0). At baseline, frequent stimulant use (1.8, 1.0-3.2) and low educational attainment (0.1, 0.0-0.8) were associated with higher 'ASRS-memory' scores. In the subsample fulfilling the ASRS-screener, 45% of the patients were 'ASRS-positive,' of whom 13% with a registered ADHD diagnosis.

CONCLUSIONS

Our findings illustrate a relationship between the ASRS-memory and -attention scores and frequent cannabis and stimulant use. Furthermore, nearly half of the subsample was 'ASRS-positive.' Patients receiving OAT might benefit from being further assessed for ADHD, but improved diagnostic methods are required.

The efficacy of integrated hepatitis C virus treatment in relieving fatigue in people who inject drugs: a randomized controlled trial

BACKGROUND

Most people who inject drugs (PWIDs) suffer from severe fatigue, and chronic hepatitis C virus (HCV) infection may play a role in this. However, there is scarce evidence about interventions that alleviate fatigue among PWIDs. The present study investigated the effect of integrated HCV treatment on fatigue in this population compared to the effect of standard HCV treatment, adjusted for sustained virological response of the HCV treatment.

METHODS

This multi-center, randomized controlled trial evaluated fatigue as a secondary outcome of integrated HCV treatment (the INTRO-HCV trial). From May 2017 to June 2019, 276 participants in Bergen and Stavanger, Norway, were randomly assigned to receive integrated and standard HCV treatment. Integrated treatment was delivered in eight decentralized outpatient opioid agonist therapy clinics and two community care centers; standard treatment was delivered in specialized infectious disease outpatient clinics at referral hospitals. Fatigue was assessed prior to treatment and 12 weeks after treatment using the nine-item Fatigue Severity Scale (FSS-9). We applied a linear mixed model to evaluate the impact of integrated HCV treatment on changes in FSS-9 (ΔFSS-9) sum scores.

RESULTS

At baseline, the mean FSS-9 sum score was 46 (standard deviation (SD): 15) for participants on integrated HCV treatment and 41 (SD: 16) for those on standard treatment. Twelve weeks after completed HCV treatment, the mean FSS-9 sum score for participants receiving integrated HCV treatment was 42 (SD: 15) and 40 (SD: 14) for those receiving standard HCV treatment. Integrated HCV treatment did not reduce the FSS-9 scores compared to standard HCV treatment (ΔFSS-9: -3.0, 95% confidence interval (CI): -6.4;0.4).

CONCLUSIONS

Fatigue is a common symptom among PWIDs. Integrated HCV treatment is at least equal to standard HCV treatment in improving fatigue.

TRIAL REGISTRATION

ClinicalTrials.gov.no NCT03155906, 16/05/2017.

Impact of liver fibrosis and clinical characteristics on dose-adjusted serum methadone concentrations

BACKGROUND

There is limited knowledge on the causes of large variations in serum methadone concentrations and dose requirements.

OBJECTIVES

We investigated the impact of the degree of liver fibrosis on dose-adjusted steady-state serum methadone concentrations.

METHODS

We assessed the clinical and laboratory data of 155 Norwegian patients with opioid use disorder undergoing methadone maintenance treatment in outpatient clinics in the period 2016-2020. A possible association between the degree of liver fibrosis and dose-adjusted serum methadone concentration was explored using a linear mixed-model analysis.

RESULTS

When adjusted for age, gender, body mass index, and genotypes of CYP2B6 and CYP3A5, the concentration-to-dose ratio of methadone did not increase among the participants with liver fibrosis (Coefficient: 0.70; 95% CI: -2.16, 3.57; P: 0.631), even among those with advanced cirrhosis (-0.50; -4.59, 3.59; 0.810).

CONCLUSIONS

Although no correlation was found between the degree of liver stiffness and dose-adjusted serum methadone concentration, close clinical monitoring should be considered, especially among patients with advanced cirrhosis. Still, serum methadone measurements can be considered a supplement to clinical assessments, taking into account intra-individual variations.

Harm reduction and abstinence-based models for treatment of substance use disorders during the COVID-19 pandemic: a global perspective

The COVID-19 pandemic has significantly affected treatment services for people with substance use disorders (SUDs). Based on the perspectives of service providers from eight countries, we discuss the impact of the pandemic on SUD treatment services. Although many countries quickly adapted in provision of harm reduction services by changes in policy and service delivery, some went into a forced abstinence-based strategy. Similarly, disruption of abstinence-based approaches such as therapeutic communities has been reported. Global awareness is crucial for responsible management of SUDs during the pandemic, and the development of international health policy guidelines is an urgent need in this area.

Effectiveness and Safety of Low-Threshold Opioid-Agonist Treatment in Hard-To-Reach Populations with Opioid Dependence

OBJECTIVES

Opioid-use disorder is related to premature death worldwide. Opioid-agonist treatment (OAT) is an effective treatment for opioid dependence. OAT delivery platforms may influence treatment access and outcomes, especially for the most vulnerable groups. The aim of this study was to determine the effectiveness and safety of low-threshold OAT compared to the standard treatment.

METHODS

Patients with diagnosed opioid dependence undergoing low-threshold OAT at the Bergen delivery platform in Norway were enrolled in a cohort study in 2014-2019. A national OAT cohort was the reference group. The main outcomes were treatment retention, the use of illicit opioids, non-fatal overdose, overdose death, and all-cause mortality during the first year following treatment initiation and the full treatment period. Additionally, healthcare utilization in the periods before and during OAT was investigated.

RESULTS

Compared to the reference cohort, the low-threshold cohort (n = 128, mean age: 38 years, women: 28%) showed treatment retention rates of 95% versus 92%, illicit opioid use of 7% versus 10%, non-fatal overdose of 7% versus 6%, and death at 1.0% versus 1.3%, respectively. The incident rate ratios (IRRs) for healthcare utilization increased substantially during the OAT period compared to the period before; the IRR increased by 3.3 (95% confidence interval (CI): 2.8, 3.9) and 3.4 (95% CI: 3.1, 3.9) for all in- and outpatient healthcare, respectively.

CONCLUSIONS

Low-threshold OAT was at least as effective and safe as the standard OAT in terms of treatment retention, the use of illicit opioids, non-fatal overdose, and death. Healthcare utilization increased during the OAT compared to the period before. Lowering the threshold for OAT entrance within proper delivery platforms should be broadly considered to reduce harm and improve healthcare access among patients with opioid dependence.

Changes in substance use during outpatient treatment for substance use disorders: a prospective Norwegian cohort study from 2016 to 2020

Background

Continuous use of amphetamines, alcohol, benzodiazepines, cannabis, cocaine, or opioids contributes to health impairments, increased morbidity, and overdose deaths among patients with substance use disorders (SUDs). This study evaluates the impact of inpatient detoxification, injecting substance use, age, and gender on substance use over time among patients undergoing outpatient SUD treatment.

Methods

We used data from a cohort of SUD patients in Norway obtained from health assessments of self-reported substance use and sociodemographic and clinical factors. A total of 881 substance use measurements, including substances and frequency of use, were assessed for 708 SUD patients in 2016–2020. Of those, 171 patients provided two or more substance use measurements. The total substance use was calculated, creating a substance use severity index (SUSI), ranging from zero (no use) to one (daily use of all substances). We defined baseline as the first substance use measurement when the measurements were listed chronologically. Time was defined as years from baseline. We used a linear mixed model to analyze the SUSI at baseline and over time, and its associations with inpatient detoxification, injecting substance use, gender, and age, presented with coefficients and 95% confidence intervals (CI).

Results

No longitudinal changes in the SUSI were found compared with baseline (change in SUSI (cSUSI): 0.04, 95% CI: − 0.05;0.13, p = 0.397). Likewise, “inpatient detoxification” was not associated with changes in the SUSI compared with “no inpatient detoxification” (cSUSI: 0.00, 95% CI: − 0.04;0.04, p = 0.952). However, injecting substances were associated with a higher SUSI than not injecting substances at baseline (difference in SUSI: 0.19, 95% CI: 0.16;0.21, p = < 0.001), and starting to inject substances was associated with increasing SUSI over time compared with not starting to inject substances (cSUSI: 0.11, 95% CI: 0.07;0.15, p = < 0.001). Gender was not significantly associated with changes in the SUSI (cSUSI: − 0.04, 95% CI: − 0.07;0.00, p = 0.052), while patients over 60 years of age had a lower SUSI than those under the age of 30 at baseline (difference in SUSI: − 0.08, 95% CI: − 0.14;− 0.01, p = 0.018), with no change over time (cSUSI: − 0.05, 95% CI: − 0.16;0.05, p = 0.297).

Conclusion

The present study demonstrates that inpatient detoxification was not associated with substance use changes over time for patients undergoing outpatient SUD treatment. Otherwise, injecting substance use was a particular risk factor for a high level of substance use. Future research needs to evaluate the impact of other treatment approaches on substance use, ideally in randomized controlled trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13011-021-00403-9.

Integrated treatment of hepatitis C virus infection among people who inject drugs: A multicenter randomized controlled trial (INTRO-HCV)

BACKGROUND

The standard pathways of testing and treatment for hepatitis C virus (HCV) infection in tertiary healthcare are not easily accessed by people who inject drugs (PWID). The aim of this study was to evaluate the efficacy of integrated treatment of chronic HCV infection among PWID.

METHODS AND FINDINGS

INTRO-HCV is a multicenter, randomized controlled clinical trial. Participants recruited from opioid agonist therapy (OAT) and community care clinics in Norway over 2017 to 2019 were randomly 1:1 assigned to the 2 treatment approaches. Integrated treatment was delivered by multidisciplinary teams at opioid agonist treatment clinics or community care centers (CCCs) for people with substance use disorders. This included on-site testing for HCV, liver fibrosis assessment, counseling, treatment, and posttreatment follow-up. Standard treatment was delivered in hospital outpatient clinics. Oral direct-acting antiviral (DAA) medications were administered in both arms. The study was not completely blinded. The primary outcomes were time-to-treatment initiation and sustained virologic response (SVR), defined as undetectable HCV RNA 12 weeks after treatment completion, analyzed with intention to treat, and presented as hazard ratio (HR) and odds ratio (OR) with 95% confidence intervals. Among 298 included participants, 150 were randomized to standard treatment, of which 116/150 (77%) initiated treatment, with 108/150 (72%) initiating within 1 year of referral. Among those 148 randomized to integrated care, 145/148 (98%) initiated treatment, with 141/148 (95%) initiating within 1 year of referral. The HR for the time to initiating treatment in the integrated arm was 2.2 (1.7 to 2.9) compared to standard treatment. SVR was confirmed in 123 (85% of initiated/83% of all) for integrated treatment compared to 96 (83% of initiated/64% of all) for the standard treatment (OR among treated: 1.5 [0.8 to 2.9], among all: 2.8 [1.6 to 4.8]). No severe adverse events were linked to the treatment.

CONCLUSIONS

Integrated treatment for HCV in PWID was superior to standard treatment in terms of time-to-treatment initiation, and subsequently, more people achieved SVR. Among those who initiated treatment, the SVR rates were comparable. Scaling up of integrated treatment models could be an important tool for elimination of HCV.

TRIAL REGISTRATION

ClinicalTrials.gov.no NCT03155906.

Subjective symptoms and serum methadone concentrations: what should guide dose adjustments in methadone maintenance treatment? A naturalistic cohort study from Norway

BACKGROUND

There is little evidence-based guidance on how to optimize methadone dosages among patients with opioid addiction undergoing methadone maintenance treatment (MMT). This study aims to investigate whether self-perceived opioid withdrawal symptoms, adverse effects, and self-reported substance use in patients on MMT are related to serum methadone concentrations and the role that these variables could play in clinical decisions on dose adjustments.

METHODS

This naturalistic prospective cohort study included clinical and laboratory measurements from 83 patients undergoing MMT in outpatient clinics in Bergen, Norway, from May 2017 to January 2020. Information on age, gender, methadone daily doses and serum concentrations, subjective opioid withdrawal symptoms using 16 items Subjective Opioid Withdrawal Scale (SOWS) questionnaire, self-reported adverse effects, and substance use was obtained. Linear mixed modelling was used for analyzing the data.

RESULTS

The mean age of the participants was 45 years, and 33% were women. Almost half reported mild to moderate subjective opioid withdrawal symptoms, and all had experienced at least one subjective adverse effect. The use of at least one substance was reported by 88% of the participants. Serum concentration-to-dose ratios were lower among those who had reported subjective opioid withdrawal symptoms (p) = 0.039). The total SOWS score (p < 0.001); the specific subjective withdrawal symptoms of anxiety (p = 0.004), bone and muscle aches (p = 0.003), restlessness (p = 0.017), and (slightly) shaking (p = 0.046), also use of heroin (p = 0.015) and alcohol (p = 0.011) were associated with lower methadone concentrations. Cannabis use was slightly related to higher methadone concentrations (p = 0.049).

CONCLUSIONS

The findings suggest that the patient's self-perceived symptoms and current clinical condition are related to the serum concentrations of methadone. This interpretation supports dose adjustments based on patient-reported symptoms. In some aberrant cases, measurement of serum concentrations together with other individual assessments may be considered to support the clinical decision.

Impact of clinical and sociodemographic factors on fatigue among patients with substance use disorder: a cohort study from Norway for the period 2016-2020

Background

The impact of clinical and sociodemographic factors on fatigue remains unknown among patients with substance use disorders (SUD). This study aims to evaluate fatigue among patients with SUD using a nine-item fatigue severity scale (FSS-9) and identify the impact that clinical and sociodemographic factors – such as injecting substance use, chronic infectious diseases, liver fibrosis, opioid agonist therapy (OAT), debt difficulties, and housing situation – have on fatigue.

Methods

We used data from a cohort of patients with SUD in Norway with annual health assessments surveying FSS-9 and some clinical and sociodemographic factors. A total of 915 FSS-9 measurements were collected from 654 patients during the period 2016–2020. We defined baseline as the first annual health assessment when the health assessments were listed chronologically. Time was defined as years from baseline. We used a linear mixed model to analyse whether the clinical and sociodemographic factors affected the FSS-9 sum score, presented with beta coefficients (β) with 95% confidence intervals (CI).

Results

The mean sum score of the FSS-9 was 43 (standard deviation: 16) at baseline. Females compared with males (adjusted mean difference of FSS-9 sum score: 4.1, 95% CI: 1.3–7.0), having debt difficulties compared with having no debt difficulties (2.9;0.4–5.3), and frequent use of benzodiazepines (5.7;3.0–8.4) or amphetamines (-5.0;-8.0– -2.0) compared to less frequent or no use of these substances changed the FSS-9 baseline sum score. The other clinical and sociodemographic factors did not predict any clinically relevant change in the FSS-9 sum score from baseline to the following health assessments.

Conclusion

Patients with SUD suffer from high levels of fatigue. Female patients, patients with debt difficulties, and those with extensive use of benzodiazepines are at particular risk of being fatigued. This should be taken into consideration when planning health services.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13011-020-00334-x.

On the path towards universal coverage of hepatitis C treatment among people receiving opioid agonist therapy (OAT) in Norway: a prospective cohort study from 2013 to 2017

OBJECTIVES

We aimed to calculate cumulative hepatitis C virus (HCV) treatment coverage among individuals enrolled in opioid agonist therapy (OAT) in Norway between 2013 and 2017 and to document the treatment transition to direct-acting antiviral (DAA) agents. Moreover, we aimed to describe adherence to DAAs in the same cohort.

DESIGN

Prospective cohort, registry data.

SETTING

Specialist healthcare service (secondary) PARTICIPANTS AND OUTCOMES: This observational study was based on data from The Norwegian Prescription Database. We studied dispensed OAT and HCV treatment annually to calculate the cumulative frequency, and employed secondary sources to calculate prevalence, incidence and HCV treatment coverage from 2013 to 2017, among the OAT population. Factors associated with adherence to DAAs were identified a priori and subject to logistic regression.

RESULTS

10 371 individuals were identified with dispensed OAT, 1475 individuals of these were identified with dispensed HCV treatment. Annual HCV treatment coverage increased from 3.5% (95% CI: 3.2 to 4.4) in 2013 to 17% (95% CI: 17 to 20) in 2017, giving a cumulative HCV coverage among OAT patients in Norway of 38.5%. A complete shift to interferon-free treatment regimens occurred, where DAAs accounting for 32% of HCV treatments in 2013 and 99% in 2017. About two-thirds of OAT patients were considered adherent to their DAA regimens across all genotypes. High level of OAT continuity was associated with improved adherence to DAAs (adjusted OR 1.4, 95% CI: 1 to 2, p=0.035).

CONCLUSIONS

A large increase in HCV treatment coverage attributed by a complete shift to interferon-free regimens among the Norwegian OAT population has been demonstrated. However, treatment coverage is inadmissibly too low and a further substantial scale-up in HCV treatment is required to reach the universal targets of controlling and eliminating the HCV endemic.

Potentially addictive drugs dispensing to patients receiving opioid agonist therapy: a register-based prospective cohort study in Norway and Sweden from 2015 to 2017

OBJECTIVES

To compare the use of benzodiazepines, z-hypnotics, gabapentinoids, opioids and centrally acting stimulants (CAS) among patients who had received opioid agonist therapy (OAT) in Norway and Sweden during the period 2015 - 2017.

DESIGN

A register-based prospective cohort study using information about dispensed drugs from the Norwegian Prescription Database and Swedish Prescribed Drug Register.

SETTING

Patients who were dispensed OAT opioids from pharmacies.

PARTICIPANTS

A total of 7176 Norwegian and 3591 Swedish patients on OAT were included.

OUTCOME MEASURES

The number and frequency of potentially addictive drugs dispensed were calculated for the two countries. The mean daily doses of dispensed benzodiazepines and z-hypnotics were summarised by calculating benzodiazepines in diazepam equivalents and z-hypnotics in zopiclone equivalents.

RESULTS

In 2017, 46% of patients in Norway, and 15% in Sweden, were dispensed a benzodiazepine. Moreover, 14% in Norway and 26% in Sweden received z-hypnotics. Gabapentinoids were dispensed to 10% of patients in Norway and 19% of patients in Sweden. In Norway, 6% and 12% of the patients received strong and weak non-OAT opioids, respectively, whereas in Sweden 10% were dispensed strong non-OAT opioids and 5% weak non-OAT opioids . CAS were dispensed to 4% in Norway and 18% in Sweden. The mean daily doses of benzodiazepines were 16 and 17 mg diazepam equivalents in Norway and Sweden, respectively. For z-hypnotics, the mean daily dose was 8 mg zopiclone equivalents in both countries. 'Benzodiazepines and z-hypnotics' was the most dispensed drug combination in 2017. Similar results were found in 2015 and 2016.

CONCLUSIONS

Nearly half of those patients who were dispensed an OAT opioid in Norway and Sweden were dispensed potentially addictive drugs. The differences identified between Norway and Sweden might be related to differences in eligibility guidelines and restrictions with respect to OAT.

Uptake and predictors of direct-acting antiviral treatment for hepatitis C among people receiving opioid agonist therapy in Sweden and Norway: a drug utilization study from 2014 to 2017

Background

Treatment with direct-acting antiviral agents (DAAs) offers an opportunity to eliminate hepatitis C virus (HCV) endemic among people who inject drugs (PWID) and people enrolled in opioid agonist therapy (OAT) programs. The objective of this study was to estimate and to compare HCV treatment uptake after the introduction of DAAs among patients receiving OAT in Sweden and Norway. We also aimed to evaluate predictors of DAAs treatment among OAT patients in both countries.

Methods

This observational study was conducted with data from The Swedish Prescribed Drug Register and The Norwegian Prescription Database. We studied dispensed medications to calculate HCV treatment among OAT patients from 2014 to 2017 in Sweden and Norway. HCV prevalence was estimated from primary and secondary sources. Dispensations of medicines from different therapeutic areas, which served as proxy for co-morbidities in 2017, were conditionally adjusted for age, gender, and OAT medications. Logistic regression was used to evaluate these parameters.

Results

In total 3529 individuals were identified with dispensed OAT in the Swedish cohort and 7739 individuals in the Norwegian cohort. HCV treatment was utilized by 407 persons in Sweden and 920 in Norway during the study period. Annual HCV and DAA treatment uptake increased in both countries. The estimated cumulative HCV treatment uptake at the end of 2017 was 31% in Norway and 28% in Sweden. DAA treatment was associated with increased age (aOR 1.8; 95% CI 1.0–3.2) and the dispensation of drugs used for diabetes (aOR 3.2; 95% CI 1.8–5.7) in Sweden. In Norway, lipid modifying agents and antibacterials were associated with decreased odds (aOR 0.4; 95%CI 0.2–0.9, aOR 0.8; 95%CI 0.6–1.0).

Conclusions

An increase in DAA treatment and HCV treatment uptake was observed among Swedish and Norwegian OAT patients whilst introducing new direct-acting antiviral treatment regimens. However, more than two thirds of the OAT population in Norway and Sweden were untreated at the beginning of 2018. A further scale-up is crucial in order to control and eliminate the HCV endemic among OAT patients.

Dispensations of benzodiazepines, z-hypnotics, and gabapentinoids to patients receiving opioid agonist therapy; a prospective cohort study in Norway from 2013 to 2017

Background

Dispensations of benzodiazepines, z-hypnotics, and gabapentinoids to patients on opioid agonist therapy (OAT) are common and have pros and cons. The objectives of the current study are to define the dispensation rates of these potentially addictive drugs, and whether the number and the mean daily doses of dispensed OAT opioids and discontinuing OAT, are associated with being dispensed benzodiazepines, z-hypnotics and gabapentinoids among patients on OAT in Norway in the period 2013 to 2017.

Methods

Information about all dispensed opioids, benzodiazepines, z-hypnotics and gabapentinoids were recorded from the Norwegian Prescription Database (NorPD). A total of 10,371 OAT patients were included in the study period. The dispensation rates were defined as the number of patients who were dispensed at least one of the potentially addictive drugs divided among the number of patients who have dispensed an OAT opioid per calendar year. Mean daily doses were calculated, and for benzodiazepines and z-hypnotics, stated in diazepam equivalents. The association between dispensed potentially addictive drugs, and the number and the type of dispensed OAT opioids were calculated by using logistic regression models.

Results

Half of the OAT patients received at least one dispensation of a benzodiazepine or z-hypnotic, and 11% were dispensed at least a gabapentinoid in 2017. For dispensed benzodiazepines or z-hypnotics, the mean daily dose was reduced from 21 mg (95% confidence interval (CI): 20–23) diazepam equivalents in 2013 to 17 mg (95% CI: 16–17) in 2017. The mean daily dose of pregabalin increased from 365 mg (95% CI: 309–421) in 2013 to 386 mg (95% CI: 349–423) in 2017. Being dispensed a gabapentinoid (adjusted odds ratio (aOR) = 2.5, 95% CI: 2.1–3.0) or a non-OAT opioid (aOR = 3.0, 95% CI: 2.6–3.5) was associated with being dispensed a benzodiazepine or z-hypnotic. Discontinuing OAT did not affect the number of dispensations and the doses of potentially addictive drugs.

Conclusion

The dispensation rates of potentially addictive drugs are high in the OAT population. Treatment indications, as well as requirements for prescription authority, need to be debated and made explicit. Randomized controlled trials evaluating the benefits and risks of such co-prescription are required.

Dispensation of attention deficit hyperactivity disorder (ADHD) medications in patients receiving opioid agonist therapy; a national prospective cohort study in Norway from 2015 to 2017

BACKGROUND

It is estimated that up to a third of patients on opioid agonist therapy (OAT) have attention deficit hyperactivity disorder (ADHD). Treatment by ADHD medication, including a centrally acting stimulant (CAS) or atomoxetine is one of the essential approaches. This study evaluates the use of dispensed ADHD medications in the Norwegian OAT population in the period from 2015 to 2017. Types and doses of ADHD medications, co-dispensations of other potentially addictive drugs like benzodiazepines, z-hypnotics, gabapentinoids, and non-OAT opioids, as well as direct-acting antivirals (DAA) against hepatitis C infection, are investigated.

METHODS

Information about all dispensed ADHD medication, OAT opioids, and the defined potentially addictive drugs were recorded from the Norwegian Prescription Database. Dispensation rates, the types, and the doses of dispensed ADHD medications were estimated by summarizing the number of dispensations, and the dispensed doses. Logistic regression analyses were employed to assess the associations between ADHD medication, and OAT opioid use, and dispensations of other potentially addictive drugs and DAAs against hepatitis C infection.

RESULTS

A total of 9235 OAT patients were included. The proportion of patients who were dispensed ADHD medication increased from 3.5 to 4.6% throughout the study period. The three most dispensed CAS were short- and intermediate-acting methylphenidate (55%), lisdexamphetamine (24%), and dexamphetamine (17%) in 2017. Buprenorphine, rather than methadone, as OAT opioid (adjusted odds ratio: 1.6, CI: 1.2-2.1) was associated with being dispensed ADHD medication. Among patients who received CAS and OAT opioids each calendar year, the dispensed doses of methylphenidate increased from 63 mg/day in 2015 to 76 mg/day in 2017 (p = 0.01). Sixty percent of patients receiving ADHD medications were also dispensed other addictive drugs concomitantly in 2017. Similar results were found in 2015 and 2016.

CONCLUSION

Co-prescription of ADHD medications was low among patients on OAT in Norway, considering a high prevalence of ADHD in this patient group. On the other hand, concurrent dispensations of multiple addictive drugs were common in this population. Understanding the underlying reasons for such prescribing is essential, and research on how to optimize ADHD medication of patients with ADHD receiving OAT is needed.

Integrated treatment of hepatitis C virus infection among people who inject drugs: study protocol for a randomised controlled trial (INTRO-HCV)

Background

A large proportion of people who inject drugs (PWID) living with hepatitis C virus (HCV) infection have not been treated. It is unknown whether inclusion of HCV diagnostics and treatment into integrated substance use disorder treatment and care clinics will improve uptake and outcome of HCV treatment in PWID. The aim is to assess the efficacy of integrating HCV treatment to PWID and this paper will present the protocol for an ongoing trial.

Methods

INTRO-HCV is a multicentre, randomised controlled clinical trial that will compare the efficacy of integrated treatment of HCV in PWID with the current standard treatment. Integrated treatment includes testing for HCV, assessing liver fibrosis with transient elastography, counselling, treatment delivery, follow-up and evaluation provided by integrated substance use disorder treatment and care clinics. Most of these clinics for PWID provide opioid agonist therapy while some clinics provide low-threshold care without opioid agonist therapy. Standard care involves referral to further diagnostics, treatment and treatment follow-up given in a hospital outpatient clinic with equivalent medications. The differences between the delivery platforms in the two trial arms involve use of a drop-in approach rather than specific appointment times, no need for additional travelling, less blood samples taken during treatment, and treatment given from already known clinicians. The trial will recruit approximately 200 HCV infected individuals in Bergen and Stavanger, Norway. The primary outcomes are time to treatment initiation and sustained virologic response, defined as undetectable HCV RNA 12 weeks after end of treatment. Secondary outcomes are cost-effectiveness, treatment adherence, changes in quality of life, fatigue and psychological well-being, changes in drug use, infection related risk behaviour, and risk of reinfection. The target group is PWID with HCV diagnosed receiving treatment and care within clinics for PWID.

Discussion

This study will inform on the effects of an integrated treatment program for HCV in clinics for PWID compared to standard care aiming to increase access to treatment and improving treatment adherence. If the integrated treatment model is found to be safe and efficacious, it can be considered for further scale-up.

Trial registration

ClinicalTrials.gov.no. NCT03155906.

Integrated care of severe infectious diseases to people with substance use disorders; a systematic review

BACKGROUND

Various integrated care models have been used to improve treatment completion of medications for chronic hepatitis B virus (HBV), chronic hepatitis C virus (HCV), Mycobacterium tuberculosis (TB), and Human immunodeficiency virus (HIV) among people with substance use disorders (SUD). We have conducted a systematic review to evaluate whether integrated models have impacts of the treatment of infectious diseases among marginalized people with SUD.

METHODS

We searched MEDLINE/PubMed (1946 to 2018, on July 26, 2018) and Embase (from 1974 to 2018, on July 26, 2018) for randomized controlled trials (RCTs) and cohort studies evaluating diverse integrated models' effects on sustained virological response (SVR), HIV suppression, HBV curation or suppression, completion of TB treatment regimen among people with SUD. The included studies were assessed qualitatively.

RESULTS

Altogether, 1640 studies, and references to 1135 related reviews and RCTs were considered, and only seven RCTs and three cohort studies fulfilled the inclusion criteria. We identified nine integrated care models. Two studies, one RCT and one cohort study, showed a significant effect of their integrated models. The RCT evaluated psychosocial treatment, opioid agonist treatment (OAT) and directly observed TB treatment, and found a significant increase in TB treatment completions among intervention group compared to control group (60% versus 13%, p < 0.01). The cohort study including OAT and TB treatments had an effect on TB treatment completion in hospitalized patients (89% versus 73%, p = 0.03). Eight out of ten studies showed no significant effects of their integrated care models on defined outcomes. One of which having included 363 participants in a RCT showed no effect on SVR compared to the control group when the results adjusted for active substance use and alcohol dependence in a post-hoc analysis (11% versus 7%, p = 0.49).

CONCLUSIONS

The findings indicate uncertainty on the effects of integrated care models' on treatment for severe infectious diseases among people with SUD. Some studies point toward that integrated models could improve care of people with SUD, yet high-quality studies and preferably, sufficiently sized clinical trials are needed to conclude on the degree of impact.

Clinical characteristics of patients with drug hypersensitivity in Norway: a single-centre study

BACKGROUND

Drug hypersensitivity reactions (DHRs) represent an important public health problem. Knowledge of their clinical characteristics will provide improved diagnostic approaches to this topic.

OBJECTIVES

The aim of the present study was to describe the clinical characteristics of patients with suspected DHRs.

METHODS

The medical records of 206 outpatients with suspected DHRs, who consulted a Norwegian allergy centre from January 2005 to December 2009, were investigated in a retrospective study.

RESULTS

Mean age (range) was 44.3 (11-84) years, and 72% of the patients were women. The most common underlying diseases justifying the use of drugs were infections (49%) and pain-related diseases (23%). Antibiotics (53%), non-steroidal anti-inflammatory drugs (NSAIDs) (32%), paracetamol (15%) and other drugs (46%), used as monotherapy or combinations, were the most often suspected drugs. Cutaneous symptoms were the most frequently reported symptoms (83%). Hospitalisation or prolonged hospitalisation was needed in 38% of the cases, and anaphylaxis was reported in 28% of all the patients. Skin prick tests were performed in 185 patients, of which 14 patients had positive test results. Drug provocation tests (DPTs) were performed in only 86 patients, six of which had positive reactions. DHRs were confirmed in 24 and rejected in 81 patients. Unsettled cases (39%) were mainly due to not performing DPTs.

CONCLUSIONS

Suspected DHRs occur predominantly in women. The most common manifestations are cutaneous symptoms, but life-threatening reactions justifying hospitalisation may occur. Antibiotics and NSAIDs are the two drug families most frequently suspected. DPTs need to be included in diagnostic protocols in order to evaluate suspected DHRs.