CYP2D6-inhibiting drugs and risk of fall injuries after newly initiated antidepressant and antipsychotic therapy in a Swedish, register-based case-crossover study

Assessment of Codispensing Patterns of Mirabegron and Prespecified CYP2D6 Substrates in Patients with Overactive Bladder

BACKGROUND

Patients with overactive bladder (OAB) experience sudden, intense urges to urinate, which may include urge urinary incontinence and nocturia. Pharmacotherapy includes β3-adrenergic receptor agonists such as mirabegron; however, mirabegron contains a label warning for cytochrome P450 (CYP) 2D6 inhibition, making coadministration with CYP2D6 substrates require monitoring and dose adjustment to avoid unintended increases in substrate concentration.

OBJECTIVE

To understand the codispensing patterns of mirabegron among patients using ten predefined CYP2D6 substrates with and before mirabegron dispensing.

METHODS

This retrospective claims database analysis used the IQVIA PharMetrics® Plus Database to assess codispensing of mirabegron with ten predefined CYP2D6 substrate groups identified on the basis of medications most frequently prescribed in the United States, those with high susceptibility to CYP2D6 inhibition, and those with evidence for exposure-related toxicity. Patients had to be ≥ 18 years old before initiation of the CYP2D6 substrate episode that overlapped with mirabegron. The cohort entry period was November 2012 to September 2019, and the overall study period was 1 January 2011 to 30 September 2019. Comparisons of patient profiles at dispensing were made between time periods with and before mirabegron use in the same patient. Descriptive statistics were used to assess the number of exposure episodes, total duration of exposure, and median duration of exposure of CYP2D6 substrate dispensing with and before mirabegron.

RESULTS

CYP2D6 substrate exposure periods totaling ≥ 9000 person-months were available before overlapping exposure to mirabegron for all ten CYP2D6 substrate cohorts. Median codispensing duration for chronically administered CYP2D6 substrates was 62 (interquartile range [IQR] 91) days for citalopram/escitalopram, 71 (105) days for duloxetine/venlafaxine, and 75 (115) days for metoprolol/carvedilol; median codispensing duration for acutely administered CYP2D6 substrates was 15 (33) days for tramadol and 9 (18) days for hydrocodone.

CONCLUSIONS

In this claims database analysis, the dispensing patterns of CYP2D6 substrates with mirabegron displayed frequent overlapping of exposure. Thus, a need exists to better understand the outcomes experienced by patients with OAB who are at increased risk for drug‒drug interactions when taking multiple CYP2D6 substrates concurrently with a CYP2D6 inhibitor.

Bupropion Mediated Effects on Depression, Attention Deficit Hyperactivity Disorder, and Smoking Cessation

Bupropion had been in use since the late 1980s as an unconventional treatment for depression. Unlike other antidepressants, bupropion has no serotonergic activity and inhibits the reuptake of norepinephrine and dopamine. The drug has been used to treat depression, Attention Deficit Hyperactivity Disorder (ADHD), and smoking cessation. This investigation reviews the pharmacokinetic and pharmacodynamic effects of bupropion and its mechanisms of action and interactions with other drugs. We evaluated the efficacy of major on and off-label uses of bupropion, focusing on the indications, benefits, and adverse effects. Our review demonstrates that bupropion is superior to placebo and non-inferior to SSRIs such as escitalopram in treating major depressive disorder. More research is needed to determine positive patient-centered outcomes such as increases in quality of life. In the case of ADHD, the evidence for efficacy is mixed with poorly conducted randomized clinical trials, small sample sizes, and a lack of long-term assessments. The same is true in the case of bipolar disorder in which there is still limited and controversial data available on bupropion's safety and efficacy. In the case of smoking cessation, bupropion is found to be an effective anti-smoking drug with synergistic benefits when used as a combination therapy. We conclude that bupropion has the potential to provide benefit for a subset of patients who do not tolerate other typical antidepressants or anti-smoking therapies or for those whose treatment goals align with bupropion's unique side effect profile, such as smokers who wish to quit and lose weight. Additional research is needed to determine the drug's full clinical potential, particularly in the areas of adolescent depression and combination therapy with varenicline or dextromethorphan. Clinicians should use this review to understand the varied uses of the drug and identify the situations and patient populations in which bupropion can lend its greatest benefit.

CYP2D6 Substrate Dispensing Among Patients Dispensed Mirabegron: An Administrative Claims Analysis

BACKGROUND

Overactive bladder (OAB) is characterized by the presence of bothersome urinary symptoms. Pharmacologic treatment options for OAB include anticholinergics and β₃-adrenergic agonists. Use of β₃-adrenergic agonists may result in similar treatment efficacy with a decreased side effect profile compared with anticholinergics because high anticholinergic burden is associated with cardiovascular and neurologic side effects. However, the β₃-adrenergic agonist mirabegron, one of two approved drugs within this class, is a moderate cytochrome P450 (CYP) 2D6 inhibitor, and coadministration of drugs that are CYP2D6 substrates with mirabegron may lead to adverse drug effects.

OBJECTIVE

The aim of this study was to quantify how often CYP2D6 substrates were dispensed in patients receiving mirabegron among adults of any age and among those ≥ 65 years of age.

METHODS

In this retrospective descriptive analysis, a deidentified administrative claims database in the United States, IQVIA PharMetrics^® Plus, was used to identify dispensing claims for CYP2D6 substrates and mirabegron from November 2012 to September 2019. Prevalence of CYP2D6 substrate dispensing was assessed in patients dispensed mirabegron among all adults ≥ 18 years old and additionally among a cohort of those ≥ 65 years old. Patient baseline profiles at the time of mirabegron and CYP2D6 substrate codispensing and at the time of mirabegron dispensing were compared. CYP2D6 substrates were categorized as those with the potential for increased risk of QT prolongation, with anticholinergic properties, with narrow therapeutic index (NTI), contraindicated or having a black box warning when used with CYP2D6 inhibitors, or used for depression or other psychiatric disease. Dispensing data and patient profiles were summarized descriptively.

RESULTS

Overall, 68.5% of adults ≥ 18 years old dispensed mirabegron had overlapping dispensings for one or more CYP2D6 substrate; 60.6% and 53.6% had overlapping dispensings for CYP2D6 substrates with anticholinergic properties or risk of QT prolongation, respectively. CYP2D6 substrates with NTI, contraindicated with CYP2D6 inhibitors, or for psychiatric use were codispensed in 17.7%, 16.6%, and 38.0% of adult mirabegron users, respectively. Mirabegron users receiving one or more concurrent CYP2D6 substrate were more likely to be older, have more comorbidities and baseline polypharmacy, and have increased healthcare resource utilization compared with those without concurrent CYP2D6 substrates. Commonly codispensed CYP2D6 substrates included hydrocodone, oxycodone, tramadol, metoprolol, and tamsulosin. Findings were similar for patients in the older cohort (≥ 65 years old), with 72.1% receiving overlapping CYP2D6 substrates.

CONCLUSIONS

Codispensing of CYP2D6 substrates, especially those with anticholinergic properties or risk of QT prolongation, was common among adults and older adults receiving mirabegron. Results highlight the need for improved awareness of CYP2D6 substrate prescribing among patients receiving pharmacologic treatment for OAB that inhibits the CYP2D6 pathway.

Short-Term Risk of Unintentional Poisoning After New Initiation of Central Nervous System Medications in Swedish Older Adults: A Register-Based Case-Crossover Study

Introduction

Medications acting on the central nervous system (CNS) are common causes of medication-related unintentional poisoning. Little is known about the short-term effects of CNS medications on unintentional poisoning.

Objective

This study aims to determine the short-term association between newly prescribed CNS drugs and unintentional poisoning.

Methods

We conducted a register-based case-crossover study of 9354 patients (age ≥ 50 years) with first-time hospitalization for unintentional poisoning in Sweden between 1 July, 2006 and 30 September, 2018. Newly initiated CNS medication was identified based on dispensations from the Swedish Prescribed Drug Register during 28 days prior to the unintentional poisoning event and compared with dispensations during an equally long control period. Conditional logistic regression was used to estimate the odds ratio and 95% confidence intervals.

Results

After a newly initiated CNS treatment, we found an increased risk of unintentional poisoning during the following 2 weeks with an odds ratio (95%) being 2.52 (1.98–3.21) and 1.47 (1.08–2.00) for the first and second week, respectively. The risk was elevated in all sub-groups but to a different degree with odds ratio ranges of 1.73–2.47 by age, 1.91–2.21 by sex, 1.40–2.30 by Charlson Comorbidity Index, 2.00–2.07 by neuropsychiatric comorbidity, and 1.63–2.82 by number of other medications.

Conclusions

The risk of unintentional poisoning doubles in 2 weeks following a new initiation of CNS drugs and the risk is increased across a range of population groups. Clinicians should carefully monitor signs of poisoning after such initiation among not only multimorbid older adults but also those with less comorbidity and polypharmacy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40264-022-01197-w.

Risk of Fall-Related Injuries Associated with Antidepressant Use in Elderly Patients: A Nationwide Matched Cohort Study

Previous studies have reported a higher risk of falls among tricyclic antidepressant (TCA) users compared to selective serotonin reuptake inhibitor (SSRI) users, yet SSRIs are known as a safer antidepressant class for use in older adults. This study examined the effects of antidepressant use on the risk of fall-related injuries after classifying antidepressant drugs, polypharmacy, and central nervous system (CNS) drugs by therapeutic classes and identifying factors influencing risk of fall-related injuries. A retrospective matched cohort study based on propensity scores was conducted among older adults, aged 70–89 years, who initiated antidepressant use between 1 January 2012 and 31 December 2014 using the national health insurance system senior cohort in Korea. The proportional hazard Cox regression model was used to examine the association between fall-related injuries and antidepressants. The subgroup analyses were performed to assess the risk of fall-related injuries by the number of concurrently administered medications, therapeutic classes of antidepressants, and CNS class medications. This study found that duloxetine, escitalopram, paroxetine, amitriptyline, imipramine, and trazodone significantly increased the risk of fall-related injuries in older adults. When antidepressants were prescribed to older adults, prescribers carefully considered factors including the dose, number of concurrently administered medications, and therapeutic classes of CNS.