Potentially hazardous drug interactions with psychotropics

Review of drug-drug interactions in patients with prostate cancer

OBJECTIVE

The objective of this review is to provide an overview of common drug-drug interactions (DDIs) associated with prostate cancer treatments and outline recommendations for managing polypharmacy.

DATA SOURCES

A literature search of PubMed, Embase, and CINAHL was carried out to identify pharmacokinetic and pharmacodynamic changes caused by DDIs that are relevant for prostate cancer patients, DDIs between prostate cancer therapies and co-administered medications (both prescription and over-the-counter), and measures to prevent DDIs. Medication package inserts were used to identify the impact of DDI on the prostate cancer therapy and suggested interventions.

DATA SUMMARY

No DDIs are expected for the LHRH agonists leuprolide acetate, histrelin, goserelin, or leuprolide mesylate. However, DDIs have been reported for GnRH antagonists, anti-androgens, PARP inhibitors, and taxanes. Although there are no confirmed DDIs for sipuleucel-T to date, it is not generally recommended to use sipuleucel-T concurrently with immunosuppressive medications. Interventions to prevent DDIs include the use of software that can detect clinically significant DDIs, up-to-date medication reconciliation, the inclusion of dedicated clinical pharmacists in cancer treatment teams, and patient/caregiver education.

CONCLUSIONS

Prostate cancer patients have a high risk of potential DDIs due to numerous new anti-cancer therapies, the increased use of treatment combinations, and the likelihood of comorbid conditions also requiring drug therapy. Drug-drug interaction screening software, up-to-date medication reconciliation, inclusion of oncology pharmacists on healthcare teams, and patient/caregiver education will aid the development of treatment plans that focus on achieving an optimal risk-benefit profile whilst reducing the risk of DDIs.

Effects of vitamin C on the pharmacokinetics and pharmacodynamics of nimodipine in rats

In recent years, researchers have shown a growing interest in the interactions between different pharmaceutical agents. An intriguing instance lies in the possible interaction between nimodipine and vitamin C. To investigate the pharmacokinetic and pharmacodynamic effects of vitamin C on nimodipine in rats, rats were randomly divided into a nimodipine only group and a combination group (nimodipine + vitamin C). The two groups were given intragastric administration and nimodipine blood concentrations were determined using high-performance liquid chromatography-tandem mass spectrum at different time points. Blood pressure and heart rate were measured via carotid artery cannulation. Pharmacokinetic differences were observed between the nimodipine only group and the combination group at the same dose. Compared with the nimodipine only group, the combination group's main pharmacokinetic parameters of peak concentration and area under the curve increased significantly, and the difference was statistically significant (p < 0.05); furthermore, the combination group exhibited a significant reduction in average blood pressure, while no significant effects on heart rate were observed. Vitamin C did not affect the activity of CYP450 in rat liver. The pharmacokinetic characteristics and pharmacodynamics of nimodipine were changed by vitamin C administration in rats.

Antipsychotics in Perspective: Past, Present, and Future (Article 2 of 3)

The history of antipsychotics in nursing homes is one piece of a much larger, more complex puzzle. In many ways, it reflects the virtues and limitations of the entire health care system and those who provide care. None of the issues related to the use of antipsychotics are specific to these medications or to nursing homes. After decades of effort to reduce unwarranted antipsychotics use, the current situation is still a work in progress. Many widely held assumptions and standard narratives, such as those about behavior, the place of medications in person-centered care, and the causes of inappropriate medication use are only partially correct. This second of 3 articles is not intended to discuss how to diagnose and manage behavior disorders or choose medications. Instead, it addresses the diverse perspectives and key players that have been involved and the results of their efforts. Ultimately, this will set the stage for specific recommendations (part 3) about learning from past efforts surrounding antipsychotics to identify more definitive and lasting improvements in the future.

A Systematic Review of Various In-vivo Screening Models as well as the Mechanisms Involved in Parkinson's Disease Screening Procedures

BACKGROUND

Parkinson's disease is the second most common neurological ailment. It is also known that it affects practically all other brain components, although only gradually. Animal models are mostly used to test the efficacy of treatment against a specific enzyme and aid in creating a new drug dose.

OBJECTIVE

The purpose of this review is to highlight in vivo Parkinson's disease screening approaches, as well as the mechanism of action of each drug involved in Parkinson's disease development, and discuss the limitations of each model. In addition, it also sheds light on Parkinson's disease genetic models.

METHODS

The data for the publication was gathered from databases, such as PubMed, Bentham Science, Elsevier, Springer Nature, Wiley, and Research Gate, after a thorough examination of diverse research findings linked to Parkinson's disease and its screening models.

RESULTS

Each chemical or drug has a unique mechanism for causing disease, whether through the production of reactive oxygen species or the blockage of the dopamine receptor. Almost every disease symptom, whether physical or behavioral, is covered by each of the constructed models' unique set of indicators and symptoms.

CONCLUSION

Animal models are typically used to assess a medicine's activity against a specific enzyme and aid in the creation of a new drug dose. The process, restrictions, and mechanisms interfering with the screening, as well as the level of animal suffering, must all be thoroughly reviewed before any model for screening for Parkinson's disease can be implemented.

Potential drug-drug interactions and associated factors among admitted patients with psychiatric disorders at selected hospitals in Northwest Ethiopia

BACKGROUND

Prescribing medications without potential drug-drug interactions (pDDIs) is one of the components of the rational use of medications. However, taking combined medications has resulted in life-threatening pDDIs, which are causing severe clinical outcomes for patients. This study was aimed at assessing the prevalence of pDDIs and associated factors in admitted patients with psychiatric disorders.

METHODS

An institution-based multicenter cross-sectional study was conducted among patients with psychiatric disorders admitted to a selected hospital in Northwest Ethiopia. Samples were approached through a systematic sampling method. The Statistical Package for the Social Sciences (SPSS) version 26 was used to analyze the data. Logistic regression was applied to determine the association of variables with pDDIs. A p-value of < 0.05 was statistically significant.

RESULTS

Out of 325 study participants, more than half (52.9%) were females, with a median age of 61 years. Overall, more than two-thirds (68.9%) were exposed to at least one clinically significant, either significant or serious level of pDDIs. Nearly one-fourth (23.2%) of participants had at least one serious level of pDDIs. Older patients were found more likely to have pDDIs compared to younger patients (p = 0.043). Similarly, patients with a higher number of prescribed medications (p = 0.035) and patients with longer hospital admissions (p = 0.004) were found more likely to be exposed to pDDIs than their counterparts.

CONCLUSION

In this study, a significant number of admitted patients with psychiatric problems encountered clinically significant pDDIs. As a result, healthcare providers could assess and follow patients with a combination of medications that potentially have a drug-drug interaction outcome.

Treatment pearls: Management of physical healthcare needs in patients with mental illness

ABSTRACT

Clinicians caring for persons with mental illness should be aware of increased mortality, physical problems, and health disparities in this population. This article provides a brief overview of physical health problems in the context of mental illness as well as those related to psychotropic medications, and discusses strategies to manage treatment effectively.

The Risk of Hip Fracture Due to Mirtazapine Exposure When Switching Antidepressants or Using Other Antidepressants as Add-On Therapy

Background

Antidepressants are associated with adverse effects such as sedation and hypotension, which can result in falls and fractures. Few studies have assessed the risk of hip fracture due to mirtazapine, and no known studies have assessed whether the risk of hip fracture is higher in patients taking other antidepressant medicines in combination with mirtazapine.

Objectives

This study aimed to examine the risk of hip fracture in older people due to mirtazapine use as well as switching between or concurrently using mirtazapine and other antidepressants.

Method

A matched case–control study was conducted. Cases were people aged over 65 years who were eligible for Australian Government Department of Veterans’ Affairs (DVA) benefits and who sustained a hip fracture between 2009 and 2012. Each case was matched with up to four randomly selected controls of the same gender and age (± 2 years). Multivariable conditional logistic regression was used to estimate associations between antidepressant use and hip fracture. In order to assess whether combined antidepressant effects differed from the sum of individual effects, the relative excess risk due to interaction (RERI) was calculated.

Results

The study population comprised 8828 cases and 35,310 controls. The median age of these participants was 88 years and 63% were women. The risk of hip fracture was increased for mirtazapine (continuous use: odds ratio [OR] 1.27, 95% confidence interval [CI] 1.12–1.44). The combinations associated with increased odds of hip fracture were addition of selective serotonin reuptake inhibitors (SSRIs) to mirtazapine (OR 11, 95% CI 2.2–51; RERI 7.7, 95% CI −9.0 to 24), addition of tricyclic antidepressants (TCAs) to mirtazapine (OR 14, 95% CI 1.4–132; RERI 12, 95% CI −19 to 43) and continuous use of both SSRIs and mirtazapine (OR 2.4, 95% CI 1.4–4.2; RERI 0.4, 95% CI −0.9 to 1.7). RERIs indicated that the effect of each antidepressant pair equalled the sum of the effects of individual antidepressant use. There was no evidence of dispensing of lower strength mirtazapine upon introducing TCAs and SSRIs.

Conclusions

Our results show elevated risk of hip fracture following use of mirtazapine alone and in combination with other antidepressants. The overlapping use of antidepressants may reflect the treatment of comorbidities (e.g. anxiety), switching from mirtazapine to other antidepressants, or add-on therapy. Our results highlight the risks of employing add-on therapy or switching antidepressants in older people, providing further evidence to support cautious cross-tapering where switching between antidepressants is required.

Electronic supplementary material

The online version of this article (doi:10.1007/s40801-017-0120-y) contains supplementary material, which is available to authorized users.

Risk of Hip Fracture in Older People Using Selective Serotonin Reuptake Inhibitors and Other Psychoactive Medicines Concurrently: A Matched Case-Control Study in Australia

Background

Few studies have assessed the risk of hip fracture following concurrent use of psychoactive medicines, and none has investigated combinations with selective serotonin reuptake inhibitors.

Objectives

To assess the risk of hip fracture in older people as a result of concurrent use of selective serotonin reuptake inhibitors and other psychoactive medicines.

Methods

A matched case–control design was employed. Cases were Australian Government Department of Veterans’ Affairs beneficiaries aged over 65 years who experienced a hip fracture between 2009 and 2012. Each case was matched with up to four randomly selected controls of the same age (±2 years) and sex. Medicine-hip fracture associations were estimated via conditional logistic regression. The relative excess risk due to interaction (RERI) was calculated to determine whether combined effects differed from the sum of individual effects.

Results

There were 8828 cases and 35,310 controls. The median age of subjects was 88 years and 63% were women. The risk of hip fracture was elevated for all medicines assessed individually, most notably selective serotonin reuptake inhibitors (initiation: odds ratio [OR] = 2.7, 95% confidence interval [CI] 2.1, 3.6) and opioids (initiation: OR = 2.3, 95% CI 1.9, 2.9). Combinations associated with an increased odds of hip fracture included addition of benzodiazepines to selective serotonin reuptake inhibitor therapy (OR = 3.0, 95% CI 1.9, 4.8; RERI = 0.9, 95% CI −0.5, 2.3), concurrent use of both opioids and selective serotonin reuptake inhibitors (OR = 2.2, 95% CI 1.9, 2.6; RERI = 0.1, 95% CI −0.3, 0.5), addition of opioids to selective serotonin reuptake inhibitor therapy (OR = 3.2, 95% CI 1.8, 5.5; RERI = −0.1, 95% CI −2.0, 1.7), and initiation of both benzodiazepines and selective serotonin reuptake inhibitors (OR = 4.7, 95% CI 1.7, 13; RERI = 1.3, 95% CI −3.8, 6.3). The RERI results suggested that the effect of each of these medicine combinations equalled the sum of the effects of individual medicine use.

Conclusions

In older people, the concurrent use of selective serotonin reuptake inhibitors and other psychoactive medicines increased the risk of hip fracture as much as the sum of the risks owing to individual medicine use. Our results highlight the need for prescribers to consider the sedative burden of medicines in each older patient as well as the potential for an additive risk of hip fracture when initiating additional psychoactive therapy.

Potential drug-drug interaction in Mexican patients with schizophrenia

OBJECTIVE

The aim of this study was to observe potential drug-drug interactions in the medication of Mexican schizophrenic patients.

METHODS

We performed a retrospective and cross-sectional study that was carried out in a psychiatric clinic. Only the prescriptions of patients with schizophrenia whose diagnoses were based on the DSM-IV instrument were included in this study. The Drug Interactions Checker software ( http://www.drugs.com/drug_interactions.html ) was used in this study to analyse potential drug-drug interactions.

RESULTS

In total, 86 of 126 patients were at risk of potential drug-drug interactions. Haloperidol and biperiden was the most common drug pair of 232 pairs evaluated. In our study, 13.8% of drug-drug interaction showed a major level of severity, whereas in 83.2%, the interaction was moderate. Finally, central nervous system (CNS) depression and anticholinergic effect were the main possible effects of drug-drug interaction.

CONCLUSIONS

Our results revealed a high number of patients with schizophrenia receiving two or more drugs. The potential drug-drug interactions observed in the Mexican population are consistent with the concomitant use of antipsychotics, benzodiazepines, and antidepressants prescribed in schizophrenia that could cause central nervous system (CNS) depression and anticholinergic effect. Drug-drug interaction must be considered when the patient with schizophrenia is medicated.

Drug-induced liver injury in a chronic hepatitis C patient treated by peginterferon, ribavirin and simeprevir

A 56-year-old male patient with chronic hepatitis C was treated with pegylated interferon (PEG IFN)-α-2b and ribavirin (RBV) for 72 weeks in 2006. The patient achieved an early virological response (EVR); however, hepatitis C relapsed 12 weeks after discontinuation of PEG IFN and RBV. In 2012, the patient was treated with a PEG IFN/RBV/telaprevir combination therapy. After 5 days of treatment, he suffered from a telaprevir-associated skin rash on his body and four limbs. He chose to be treated with PEG IFN and RBV until 60 weeks. He again achieved EVR but no sustained virological response. In 2014, he was treated with PEG IFN/RBV/simeprevir combination therapy. He achieved rapid virological response, but after 6 weeks of therapy, a striking elevation of serum aminotransferase level was recorded with no accompanying skin rash; he was admitted to our hospital. PEG IFN/RBV/simeprevir was stopped, but sodium valproate (400 mg/day), which had been administrated for more than 10 years to prevent epilepsy was continued. Liver biopsy revealed typical features of drug-induced liver injury. After stopping PEG IFN/RBV/simeprevir, serum aminotransferase levels soon returned to the normal range. We diagnosed this case to be simeprevir-induced hepatitis clinically and histologically. Physicians need to stay alert to the possibility of drug-induced liver injury in using simeprevir.

Efeitos cardiotóxicos resultantes da interação da risperidona com diuréticos tiazídicos

Antipsicóticos atípicos têm sua ação em doses que podem produzir efeitos colaterais importantes. A risperidona é o antipsicótico atípico de nova geração mais utilizado na atualidade e seu uso está associado a tratamento de esquizofrenia, transtornos psicóticos, episódios de mania e nos distúrbios de comportamento, entre outros. Os efeitos adversos mais importantes estão relacionados ao sistema nervoso central e autônomo, sistema endócrino e sistema cardiovascular. Neste último, pode haver efeitos inotrópicos negativos e alterações no eletrocardiograma, como prolongamento do intervalo QT, podendo causar taquicardia e arritmias. Relatamos um caso de um homem de 48 anos com história de delírio persecutório após ser ameaçado no trabalho, que estava sendo tratado com risperidona e paroxetina. Por não haver melhora, suas doses foram aumentadas e o paciente apresentou alargamento do intervalo QTc, com diminuição da amplitude da onda T e aumento da onda U, e hipocalemia. Além disso, o paciente era hipertenso e estava em uso de hidroclorotiazida. A risperidona tem o potencial de bloquear o componente rápido do canal cardíaco de potássio e isso prolonga o processo de repolarização dos ventrículos, podendo causar torsade de pointes, morte súbita e arritmias. Já a hidroclorotiazida causa hipocalemia, provocando alterações na contração e relaxamento do miocárdio. Houve interação medicamentosa grave entre duas drogas com potencial arritmogênico, o que levou às alterações no eletrocardiograma e produziu sintomas danosos ao paciente. A troca do antipsicótico atípico para um típico e da hidroclorotiazida por um diurético que não causa hipocalemia trouxe melhoras ao paciente.

Lysosomal sequestration (trapping) of lipophilic amine (cationic amphiphilic) drugs in immortalized human hepatocytes (Fa2N-4 cells)

Lipophilic (logP > 1) and amphiphilic drugs (also known as cationic amphiphilic drugs) with ionizable amines (pKa > 6) can accumulate in lysosomes, a process known as lysosomal trapping. This process contributes to presystemic extraction by lysosome-rich organs (such as liver and lung), which, together with the binding of lipophilic amines to phospholipids, contributes to the large volume of distribution characteristic of numerous cardiovascular and central nervous system drugs. Accumulation of lipophilic amines in lysosomes has been implicated as a cause of phospholipidosis. Furthermore, elevated levels of lipophilic amines in lysosomes can lead to high organ-to-blood ratios of drugs that can be mistaken for active drug transport. In the present study, we describe an in vitro fluorescence-based method (using the lysosome-specific probe LysoTracker Red) to identify lysosomotropic agents in immortalized hepatocytes (Fa2N-4 cells). A diverse set of compounds with various physicochemical properties were tested, such as acids, bases, and zwitterions. In addition, the partitioning of the nonlysosomotropic atorvastatin (an anion) and the lysosomotropics propranolol and imipramine (cations) were quantified in Fa2N-4 cells in the presence or absence of various lysosomotropic or nonlysosomotropic agents and inhibitors of lysosomal sequestration (NH4Cl, nigericin, and monensin). Cellular partitioning of propranolol and imipramine was markedly reduced (by at least 40%) by NH4Cl, nigericin, or monensin. Lysosomotropic drugs also inhibited the partitioning of propranolol by at least 50%, with imipramine partitioning affected to a lesser degree. This study demonstrates the usefulness of immortalized hepatocytes (Fa2N-4 cells) for determining the lysosomal sequestration of lipophilic amines.

Do people believe combined hazards can present synergistic risks?

The risk attributable to some hazard combinations can be greater than the sum of the risk attributable to each constituent hazard. Such "synergistic risks" occur in several domains, can vary in magnitude, and often have harmful, even life-threatening, outcomes. Yet, the extent to which people believe that combined hazards can present synergistic risks is unclear. We present the results of two experimental studies aimed at addressing this issue. In both studies, participants examined synergistic and additive risk scenarios, and judged whether these were possible. The results indicate that the proportion of people who believe that synergistic risks can occur declines linearly as the magnitude of the synergistic risk increases. We also find that people believe, despite scientific evidence to the contrary, that certain hazard combinations are more likely to present additive or weakly synergistic risks than synergistic risks of higher magnitudes. Furthermore, our findings did not vary as a simple function of hazard domain (health vs. social), but varied according to the characteristics of the specific hazards considered (specified vs. unspecified drug combinations). These results suggest that many people's beliefs concerning the risk attributable to combined hazards could lead them to underestimate the threat posed by combinations that present synergistic risks, particularly for hazard combinations that present higher synergistic risk magnitudes. These findings highlight a need to develop risk communications that can effectively increase awareness of synergistic risks.

Gene, ethnic and gender influences predisposition of adverse drug reactions to artesunate among Malaysians

CONTEXT

Artesunate (AS) and amodiaquine (AQ) are two prodrugs widely used as antimalarial agents and are metabolized by the CYP P450 2A6 (CYP 2A6) and CYP P450 2C8 (CYP 2C8) enzymes, respectively.

OBJECTIVE

In this study, we aim to investigate the association of both genes on AS and AQ's tolerabilities in the hope of identifying a pharmacogenetic approach that could be useful in prediction and prevention of adverse drug reactions (ADRs) among Malaysian population.

MATERIALS AND METHODS

In this randomized crossover study, loose and AS/AQ formulations were administered to normal healthy volunteers (n = 24) over two study phases. The drugs' tolerabilities (incidence of facial flushing, giddiness, headache, nausea, abdominal discomfort, progression of liver enzymes and neutrophil counts) were compared between the two treatment arms. Volunteers were also genotyped for the CYP2C8 and CYP2A6 variants.

RESULTS

The frequency of the CYP2A6*1B, CYP2A6*4, CYP2A6*8 and CYP2A6*9 alleles were 54.2%, 16.7%, 4.2% and 10.4%, respectively. No mutations for CYP2C8 gene were, however, detected. Most (96%) of the subjects were of the Malay ethnicity. Subjects having the CYP2A6*1B variants responsible for ultra rapid metabolism of AS suffered a significantly higher incidence of ADRs.

DISCUSSION

Our study is the first to report that CYP2A6 genotyping influences AS's ADR. Gender also plays a role where females reported more incidences of nausea (p < 0.05).

CONCLUSION

It is concluded that genetic polymorphisms of CYP2A6 as well as gender influence the side effect profiles of subjects receiving AS among this Malaysian population.

Subjective judgements of synergistic risks: a cognitive reasoning perspective

Mounting evidence that certain hazard combinations present synergistic risks for adverse outcomes, including violent crime, cancer, and species extinction, highlights the importance of understanding the risk attributable to combined hazards. However, previous studies indicate that individuals often misjudge synergistic risks as additive or sub-additive risks, and there is little research that explores the cognitive reasoning that may lead individuals to make such judgements. This study aims to fill this gap. Participants were asked to review several scenarios that described the risk magnitude presented by a combined hazard. They were required to judge whether each scenario was possible and to explain the reasoning that led to their judgement. The results show that many participants demonstrated an awareness of synergistic risk and that their reasoning was typically characterized by rudimentary knowledge of an underlying causal mechanism for the increased risk (e.g., a chemical reaction between drugs). Conversely, several participants adopted a line of reasoning that precluded the concept of synergistic risk. Many of these participants appeared to employ an additive model of risk, corresponding to the notion of 'adding' one hazard to another. Contrary to much previous research, we found little evidence to indicate that people tend to employ a sub-additive model of risk for combined hazards. Implications for future research and the improvement of risk communications concerning synergistic risks are discussed.

Advances of molecular clinical pharmacology in gastroenterology and hepatology

During developmental age, differences in pharmacodynamic reactions to several drugs may reflect polymorphisms of genes encoding drug-transporting proteins, receptors, drug targets, and gene products, whose disturbed activity sometimes plays an important role in certain diseases. Administration of drugs with a narrow therapeutic index may quite easily be associated with changes in pharmacokinetics and development of adverse drug reactions, which occasionally may cause fatalities. In such cases, polypragmasy and resulting drug interactions may enhance effects of changes in drug-metabolizing enzymes' activities. Phenotyping and genotyping of patients slowly are finding their place in some therapeutic regimens used in clinical gastroenterology and hepatology. At present, some assays to measure, for example, thiopurine S-methyltransferase activity are already commercially available. Polymorphisms of CYP450 enzymes, interleukins, and altered gene expression play an important role in some patients' various gastrointestinal tract and liver diseases. Herbal drugs also affect proinflammatory and antiinflammatory cytokine and nitric oxide balance in the body. Therapeutic use of recombined proteins, such as infliximab, natalizumab, onercept, humanized antibody to integrin α-4 β-7, or IFN-β in some large-bowel diseases increased therapeutic efficacy. IFN-α used in the patients with chronic hepatitis C improved cellular immunity in these subjects and exerted antiviral activity. Practical application of progress in pharmacogenetics, pharmacokinetics, pharmacodynamics, and use of bioproducts in novel therapeutic regimens has opened therapeutic frontiers and increased clinical safety.