Drug-drug interactions in pharmacologic management of gastroparesis

Prevalence, Attributes, and Risk Factors of QT-Interval-Prolonging Drugs and Potential Drug-Drug Interactions in Cancer Patients: A Prospective Study in a Tertiary Care Hospital

Introduction Cancer chemotherapy regimens include multiple classes of adjuvant drugs as supportive therapy. Because of the concurrent intake of other drugs (like antiemetics, antidepressants, analgesics, and antimicrobials), there is a heightened risk for possible QT interval prolongation. There is a dearth of evidence in the literature regarding the usage of QT-prolonging anticancer drugs and associated risk factors that have the propensity to prolong QT interval. The purpose was to explore the extent of the use of QT-interval-prolonging drugs and potential QT-prolonging drug-drug interactions (QT-DDIs) in cancer patients attending OPD in a tertiary-care hospital. Methods This was a hospital-based, cross-sectional, observational study. Risk stratification of QT-prolonging drugs for torsades de pointes (TdP) was done by the Arizona Center for Education and Research on Therapeutics (AzCERT)/CredibleMeds-lists, and potential QT-DDIs were determined with four online DDI-checker-software. Results In 1331 cancer patients, the overall prevalence of potential QT-prolonging drug utilization was 97.3%. Ondansetron, pantoprazole, domperidone, and olanzapine were the most frequent QT-prolonging drugs in cancer patients. The top six antineoplastics with potential QT-prolonging and torsadogenic actions were capecitabine, oxaliplatin, imatinib, bortezomib, 5-fluorouracil, and bendamustine. Evidence-based pragmatic QTc interval prolongation risk assessment tools are imperative for cancer patients. Conclusion This study revealed a high prevalence of QT-prolonging drugs and QT-DDIs among cancer patients who are treated with anticancer and non-anticancer drugs. As a result, it's critical to take precautions, stay vigilant, and avoid QT-prolonging in clinical situations. Evidence-based pragmatic QTc interval prolongation risk assessment tools are needed for cancer patients.

Impact of outpatient gastroenterology consult on pharmacotherapy and management of gastrointestinal symptoms in Parkinson's Disease

Background & aims

Gastrointestinal (GI) symptoms are common in Parkinson's Disease (PD) patients, and GI dysmotility is thought to induce motor fluctuations, requiring escalation of levodopa therapy. The role of GI consultation in managing such symptoms, however, is unclear. In this study, we investigate the possible association between GI dysmotility symptoms and escalated LEDD therapy, as well as factors associated with GI consultation for PD symptom management.

Methods

This was a retrospective case-study of 248 PD patients evaluated by outpatient neurology at Massachusetts General Brigham Healthcare from 2018 to 2022. Logistic regression, t-test, and Fisher exact tests were performed to identify factors associated with GI consult, change in LEDD with consult, and association of consultation with GI diagnoses and treatments, respectively.

Results

Among 248 PD patients, 12.9% received GI consultation despite 96.8% having GI symptoms. Bloating was the primary symptom associated with receiving GI consultation (OR 3.59 [95% CI 1.47-8.88], p = 0.005). GI consultation increased the odds of receiving GI-specific medications (78.2% vs 46.3%, p = 0.001) and specialized GI diagnoses like gastroparesis (9.4% vs 0.46%, p < 0.001) and pelvic floor dysfunction (15.6% vs 0%, p < 0.0001). Interestingly, LEDD tended not to change after GI consultation, and dysmotility symptoms, including bloating, did not predict need for higher LEDD.

Conclusions

While treating symptoms of dysmotility may not ameliorate levodopa-based motor fluctuations as much as previously thought, GI consultations are underutilized in PD, and patients who receive GI consultation are more likely to have changes in GI diagnosis and treatment.

Gastroparesis: Myths, Misconceptions, and Management

Gastroparesis (GP), a historically vexing disorder characterized by symptoms of nausea, vomiting, abdominal pain, early satiety, and/or bloating, in the setting of an objective delay in gastric emptying, is often difficult to treat and carries a tremendous burden on the quality of patients' lives, as well as the healthcare system in general. Though the etiology of GP has been fairly well defined, much work has been done recently to better understand the pathophysiology of GP, as well as to identify novel effective and safe treatment options. As our understanding of GP has evolved, many myths and misconceptions still abound in this rapidly changing field. The goal of this review is to identify myths and misconceptions regarding the etiology, pathophysiology, diagnosis, and treatment of GP, in the context of the latest research findings which have shaped our current understanding of GP. Recognition and dispelling of such myths and misconceptions is critical to moving the field forward and ultimately advancing the clinical management of what will hopefully become a better understood and more manageable disorder in the future.

Review article: An analysis of the pharmacological rationale for selecting drugs to inhibit vomiting or increase gastric emptying during treatment of gastroparesis

BACKGROUND

Drugs which can inhibit nausea/vomiting and/or increase gastric emptying are used to treat gastroparesis, mostly 'off-label'. Within each category, they act at different targets and modulate different physiological mechanisms.

AIMS

Address the questions: In gastroparesis, why should blocking one pathway causing vomiting, be more appropriate than another? Why might increasing gastric emptying via one mechanism be more appropriate than another?

METHODS

Drugs used clinically were identified via consensus opinions and reviews, excluding the poorly characterised. Their pharmacology was defined, mapped to mechanisms influencing vomiting and gastric emptying, and rationale developed for therapeutic use.

RESULTS

Vomiting: Rationale for 5-HT₃ , D₂ , H₁ or muscarinic antagonists, and mirtazapine, amitriptyline, nortriptyline, are poor. Arguments for inhibiting central consequences of vagal afferent transmission by NK₁ antagonism are complicated by doubts over effects on nausea. Gastric emptying: Confusion emerges because of side-effects of drugs increasing gastric emptying: Metoclopramide (5-HT₄ agonist, D₂ and 5-HT₃ antagonist; also blocks some emetic stimuli and causes tardive dyskinesia) and Erythromycin (high-efficacy motilin agonist, requiring low doses to minimise side-effects). Limited trials with selective 5-HT₄ agonists indicate variable efficacy.

CONCLUSIONS

Several drug classes inhibiting vomiting have no scientific rationale. NK₁ antagonism has rationale but complicated by limited efficacy against nausea. Studies must resolve variable efficacy of selective 5-HT₄ agonists and apparent superiority over motilin agonists. Overall, lack of robust activity indicates a need for novel approaches targeting nausea (e.g., modulating gastric pacemaker or vagal activity, use of receptor agonists or new targets such as GDF15) and objective assessments of nausea.

The pharmacokinetics of oral trazpiroben (TAK-906) after organic anion transporting polypeptide 1B1/1B3 inhibition: A phase I, randomized study

Trazpiroben is a dopamine D₂/D₃ receptor antagonist under development for the treatment of gastroparesis. This phase I, open‐label, randomized, two‐way crossover study (NCT04121078) evaluated the effect of single‐dose intravenous rifampin, a potent inhibitor of the organic anion transporting polypeptides (OATPs) 1B1 and 1B3, on the pharmacokinetics and safety of trazpiroben in healthy adults. The utility of coproporphyrin (CP) I and CPIII as biomarkers of OATP inhibition was also assessed. Overall, 12 participants were enrolled and randomized (1:1) into one of two treatment sequences (AB and BA). Participants received either a single oral dose of trazpiroben 25 mg (treatment A) or a single oral dose of trazpiroben 25 mg immediately after a single 30‐min intravenous infusion of rifampin 600 mg (treatment B). After a washout period of at least 7 days, participants received the other treatment. Geometric mean area under the curve from time 0 extrapolated to infinity (AUC_∞) and maximum serum concentration (C_max) of plasma trazpiroben were higher in participants receiving treatment B than those receiving treatment A (AUC_∞, 168.5 vs. 32.68 ng*h/ml; C_max, 89.62 vs. 14.37 ng/ml); corresponding geometric mean ratios (90% confidence interval) showed 5.16 (4.25–6.25) and 6.24 (4.62–8.42)‐fold increases in these parameters, respectively. In this study, trazpiroben was confirmed as a substrate of OATP1B1/1B3, and therefore co‐administration of trazpiroben with moderate to strong inhibitors of OATP1B1/1B3 is not recommended. This is also the first assessment of the utility of CPI and CPIII as endogenous biomarkers of OATP1B1/1B3 inhibition after a single intravenous dose of rifampin.

Gastroparesis: a turning point in understanding and treatment

Gastroparesis is defined by delayed gastric emptying (GE) and symptoms of nausea, vomiting, bloating, postprandial fullness, early satiety and abdominal pain. Most common aetiologies include diabetes, postsurgical and postinfectious, but in many cases it is idiopathic. Clinical presentation and natural history vary by the aetiology. There is significant morbidity and healthcare utilisation associated with gastroparesis. Mechanistic studies from diabetic animal models of delayed GE as well as human full-thickness biopsies have significantly advanced our understanding of this disorder. An innate immune dysregulation and injury to the interstitial cells of Cajal and other components of the enteric nervous system through paracrine and oxidative stress mediators is likely central to the pathogenesis of gastroparesis. Scintigraphy and 13C breath testing provide the most validated assessment of GE. The stagnant gastroparesis therapeutic landscape is likely to soon see significant changes. Relatively newer treatment strategies include antiemetics (aprepitant), prokinetics (prucalopride, relamorelin) and fundic relaxants (acotiamide, buspirone). Endoscopic pyloromyotomy appears promising over the short term, especially for symptoms of nausea and vomiting. Further controlled trials and identification of the appropriate subgroup with pyloric dysfunction and assessment of long-term outcomes are essential. This review highlights the clinical presentation, diagnosis, mechanisms and treatment advancements for gastroparesis.

Effect of Chronic Domperidone Use on QT Interval: A Large Single Center Study

GOALS

The goal of this study was to determine the effect and safety of domperidone on QTc interval at the commonly prescribed doses of 30 to 80 mg daily.

BACKGROUND

Domperidone is a dopamine receptor antagonist used for the treatment of gastroparesis. However, it has been associated with QT prolongation, ventricular arrhythmias, and sudden cardiac death.

STUDY

This study analyzed patients prescribed domperidone for treatment of gastroparesis between January 2012 and September 2017 at a single center. This study reviewed EKGs, primarily the QTc interval, taken at baseline, 2 to 6 months after initiation of domperidone, 6 to 12 months after initiation, and ≥12 months after initiation. Concurrent QTc prolonging medications were recorded for each patient. The primary endpoint was QTc prolongation >500 ms. Secondary endpoints were QTc >450 ms for males, a QTc>470 ms for females, QTc prolongation ≥20 ms above baseline, and QTc prolongation >60 ms above baseline.

RESULTS

In total, 246 patients were included for analysis (age, 46.3±17.4 y; F 209). EKGs were available for all 246 patients before treatment, 170 patients at 2 to 6 months, 135 at 6 to 12 months, and 152 patients at least 1 year after domperidone initiation.Of 246 subjects, 15 patients (6.1%, 9 female) had clinically important QTc prolongation; 11 had QTc >450 ms for males or >470 ms for females; none had QTc prolongation >500 ms; 5 (2.0%) had >60 ms over baseline and 61 (24.7%) patients had QTc increase of ≥20 ms but <60 ms from baseline.

CONCLUSIONS

Domperidone at the conventionally used doses to treat gastroparesis (30 to 80 mg/d) was associated with QTc prolongation in only 6% of patients with no QT interval reaching the point considered to be clinically significant. These data suggest that domperidone can be safely prescribed at doses of 30 to 80 mg daily for the treatment of gastroparesis.

Gut bioengineering promotes gut repair and pharmaceutical research: a review

The gastrointestinal (GI) tract has a diverse set of physiological functions, including peristalsis, immune defense, and nutrient absorptions. These functions are mediated by various intestinal cells such as epithelial cells, interstitial cells, smooth muscle cells, and neurocytes. The loss or dysfunction of specific cells directly results in GI disease, while supplementation of normal cells promotes gut healing. Gut bioengineering has been developing for this purpose to reconstruct the damaged tissues. Moreover, GI tract provides an accessible route for drug delivery, but the collateral damages induced by side effects cannot be ignored. Bioengineered intestinal tissues provide three-dimensional platforms that mimic the in vivo environment to study drug functions. Given the importance of gut bioengineering in current research, in this review, we summarize the advances in the technologies of gut bioengineering and their applications. We were able to identify several ground-breaking discoveries in our review, while more work is needed to promote the clinical translation of gut bioengineering.

Symptomatic Management of Gastroparesis

Gastroparesis is a chronic and debilitating neuromuscular disorder of the upper gastrointestinal tract. Symptoms of gastroparesis include nausea, vomiting, epigastric pain, early satiety, and weight loss. Treating gastroparesis can be difficult. Dietary changes may improve symptoms in patients with mild disease. A variety of medications can be used to treat symptoms of nausea and vomiting, although most have not been subjected to randomized controlled trials and only one is approved by the Food and Drug Administration (metoclopramide). Pain management is essential, as nearly 90% of patients report symptoms of epigastric pain. This article reviews treatment options for symptoms of gastroparesis.

Diabetic gastroparesis: current challenges and future prospects

Diabetic gastroparesis (DMGP) is a condition of delayed gastric emptying after gastric outlet obstruction has been excluded. Symptoms of nausea, vomiting, early satiety, bloating, and abdominal pain are associated with DMGP. Uncontrolled symptoms can lead to overall poor quality of life and financial burdens on the healthcare system. A combination of antiemetics and prokinetics is used in symptom control; metoclopramide is the main prokinetic available for clinical use and is the only U.S. Food and Drug Administration-approved agent in the United States. However, a black box warning in 2009 reporting its association with tardive dyskinesia and recommending caution in chronically using this agent beyond 3 months has decreased its role in clinical practice. There is an unmet need for new prokinetics with good efficacy and safety profiles. Currently, there are several new drugs with different mechanisms of action in the pipeline that are under investigation and show promising preliminary results. Surgically combining gastric electrical stimulation with pyloroplasty is considered "gold" standard. Advances in therapeutic endoscopic intervention with gastric per-oral endoscopic pyloromyotomy have also been shown to improve gastric emptying and gastroparesis (GP) symptoms. In this review, we will comment on the challenges encountered when managing patients with DMGP and provide an update on advances in drug development and endoscopic and surgical interventions.

Domperidone to Treat Symptoms of Gastroparesis: Benefits and Side Effects from a Large Single-Center Cohort

BACKGROUND

There is increased awareness about risks and benefits of using domperidone to treat gastroparesis.

AIM

To describe the outcome of treating patients with refractory gastroparesis symptoms with domperidone.

METHODS

Domperidone 10 mg QID or TID was prescribed to patients with refractory gastroparesis symptoms; follow-up obtained at 2-3 months assessing symptoms and side effects. Patients filled out Patient Assessment of Upper GI Symptoms prior to treatment and at follow-up along with Clinical Patient Grading Assessment Scale (CPGAS, +7 = completely better; 0 = no change).

RESULTS

Of 125 patients initially prescribed domperidone, 7 did not take this medication and 3 were lost to follow-up. Of the 115 known patients treated with domperidone, 88 had idiopathic, 16 diabetic, and 9 postsurgical gastroparesis. Side effects were reported by 44 patients (most common-headache, tachycardia/palpitations, diarrhea); 14 patients stopped treatment. Hundred and one patients were seen at follow-up taking domperidone (2.4 ± 2.7 months, average dose 36 ± 13 mg/day). CPGAS averaged 2.7 ± 2.7 (p < 0.01) with 69 patients reporting symptom improvement and 45 patients at least moderately improved with CPGAS ≥ 4. Improvements were seen in most symptoms, especially postprandial fullness, nausea, vomiting, and stomach fullness.

CONCLUSIONS

In this large single-center study of patients treated with domperidone, side effects necessitating discontinuing treatment occurred in 12 %. The majority of patients remaining on treatment experienced an improvement in symptoms of gastroparesis, particularly postprandial fullness, nausea, vomiting, and stomach fullness. Thus, domperidone treatment is beneficial for many patients with symptoms of gastroparesis. This study provides needed benefit and risk information concerning treating patients with domperidone. FDA IND Number: 71,089.

Potential drug-drug interactions in paediatric outpatient prescriptions in Nigeria and implications for the future

BACKGROUND

Information regarding the incidence of drug-drug interactions (DDIs) and adverse drug events (ADEs) among paediatric patients in Nigeria is limited.

METHODS

Prospective clinical audit among paediatric outpatients in four general hospitals in Nigeria over a 3-month period. Details of ADEs documented in case files was extracted.

RESULTS

Among 1233 eligible patients, 208 (16.9%) received prescriptions with at least one potential DDI. Seven drug classes were implicated with antimalarial combination therapies predominating. Exposure mostly to a single potential DDI, commonly involved promethazine, artemether/lumefantrine, ciprofloxacin and artemether/lumefantrine. Exposure mostly to major and serious, and moderate and clinically significant, potential DDIs. Overall exposure similar across all age groups and across genders. A significant association was seen between severity of potential DDIs and age. Only 48 (23.1%) of these patients presented at follow-up clinics with only 15 reporting ADEs.

CONCLUSION

There was exposure to potential DDIs in this population. However, potential DDIs were associated with only a few reported ADEs.

Novel Diet, Drugs, and Gastric Interventions for Gastroparesis

This review of the pathophysiologic basis for gastroparesis and recent advances in the treatment of patients with gastroparesis shows that there are several novel approaches to advance treatment of gastroparesis including diet, novel prokinetics, interventions on the pylorus, and novel forms of gastric electrical stimulation. The field of gastroparesis is likely to advance with further studies, with help from a guidance document from the Food and Drug Administration on gastroparesis, and with recent approval of the stable isotope gastric emptying test to ensure eligibility of participants in multicenter trials. Clinical experience and a formal, randomized, controlled trial provide insights on optimizing dietary interventions in patients with gastroparesis. This review addresses the biologic rationale of these different treatments, based on known physiology and pathophysiology of gastric emptying. The novel medications include the motilin agonist, camicinal; 5-HT4 receptor agonists, such as velusetrag; and the ghrelin agonist, relamorelin. New approaches target pylorospasm by stent placement, endoscopic pyloric myotomy, or laparoscopic pyloroplasty. These approaches offer the opportunity to achieve more permanent reduction of resistance to flow at the pylorus over the intrapyloric injection of botulinum toxin, which typically has to be repeated every few months if it is efficacious. A novel device, deployed in porcine stomach, involved per-endoscopic electrical stimulation. These promising approaches require formal, randomized, controlled trials and deployment in patients. The presence of concomitant antral hypomotility may be a significant factor in the responsiveness to interventions at the pylorus.

Drug-resin drug interactions in patients with delayed gastric emptying: What is optimal time window for drug administration?

Most drug-drug interactions involve overlap or competition in drug metabolic pathways. However, there are medications, typically resins, whose function is to bind injurious substances such as bile acids or potassium within the digestive tract. The objective of this article is to review the functions of the stomach and the kinetics of emptying of different food forms or formulations to make recommendations on timing of medication administration in order to avoid intragastric drug interactions. Based on the profiles and kinetics of emptying of liquid nutrients and homogenized solids, a window of 3 h between administration of a resin drug and another 'target' medication would be expected to allow a median of 80% of medications with particle size <1 mm to empty from the stomach and, hence, avoid potential interaction such as binding of the 'target' medication within the stomach.

Current and Emerging Medical Therapies for Gastroparesis

OPINION STATEMENT

Gastroparesis likely involves various pathophysiological disorders and is increasingly prevalent as complications of surgeries, medications, and chronic diabetes. Key to diagnosis is evidence of delayed gastric emptying, generally based on standardized scintigraphy, and ruling out distal obstruction or other dysmotilities. Initial medical management includes reviewing potentially exacerbating medications and ruling out other reversible causes, achieving tighter glucose control in diabetics, and implementing dietary and lifestyle changes. While current available medications are limited, symptomatic control is aimed at improving gastric emptying, alleviating nausea and vomiting, and treating associated abdominal pain. Other potential therapies are aimed at reducing acid production, improving gastric accommodation or pyloric dysfunction, and treating bacterial overgrowth. Future studies should be aimed toward identification of subpopulations of gastroparetics who are better responders to the various medications based on differences in underlying pathophysiology and adopting standardized study end point measures that may allow for comparisons across trials. This chapter will review current treatment options, upcoming promising medications, and some of the hurdles in advancing the field forward.

Postanesthesia Care for the Elderly Patient

PURPOSE

As the general population lives longer, the perioperative physician is more likely to encounter disease states that increase in incidence in an aging population. This review focuses on anesthetic considerations for rational drug choices during the perioperative care of elderly patients. The primary aim of the review was to identify intraoperative and postanesthetic considerations for diseases associated with advancing age; it includes highlights of the commonly impaired major organs (eg, cardiovascular, pulmonary, neurologic, renal, hepatic systems). We also outline an approach to frequent issues that arise in the immediate postsurgical period while caring for these patients.

METHODS

A systematic review was performed on aspects of the perioperative and postoperative periods that relate to the elderly. A list of pertinent key words was derived from the authors, and a PubMed database search was performed.

FINDINGS

The anesthesiologist must account for changes in various organ systems that affect perioperative care, including the cardiovascular, pulmonary, renal, hepatic, and central nervous systems. The pharmacokinetic principles frequently differ and are often unpredictable because of anatomic changes and decreased renal and hepatic function. The most important pharmacodynamic consideration is that elderly patients tend to exhibit an exaggerated hypoactivity after anesthesia.

IMPLICATIONS

Before surgery, it is essential to identify those patients at risk for delirium and other commonly encountered postanesthesia scenarios. Failure to manage these conditions appropriately can lead to an escalation of care and prolonged hospitalization.