The relationship between long-term proton pump inhibitor therapy and skeletal frailty

Proton pump inhibitor use and bone fractures in patients with chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) are at high risk for bone fractures, which are associated with high morbidity and mortality. Proton pump inhibitors (PPI) have been linked to an increased risk for fractures in the general population as well as in patients with need for hemodialysis, but studies in patients with CKD are currently missing.

METHODS

We performed a population-based observational case-control study exploring a sample of patients with CKD derived from the IQVIATM Disease Analyzer database. Patients with and without fractures were matched using the 1:1 nearest neighbor propensity score matching method. To investigate the association between PPI use and fractures, multivariable logistic regression analyses were performed adjusting for confounding factors.

RESULTS

In total, 6076 patients with and 6076 patients without fractures were matched and subsequently available for analyses. In the total cohort, PPI use was associated with an increased risk for fractures [odds ratio (OR) 1.68; 95% confidence interval (95% CI) 1.55-1.83]. This association was noted for nearly all types of fractures. The strongest association between PPI use and fractures was found in patients below the age of 60 years with a PPI prescription for longer than 2 years (OR 6.85; 95% CI 1.85-25.38). The same was true when analyzing cumulative PPI doses. Here, patients below the age of 60 years with a cumulative PPI dose above 16 000 mg (highest quartile) had the highest risk for fractures (OR 4.62; 95% CI 1.87-11.44). There was no difference between men or women regarding the association between PPI use and fractures.

CONCLUSIONS

This study provides evidence that PPI use is associated with fractures in patients with CKD. Deprescription of PPI in patients without an indication for treatment could be a modifiable risk factor to reduce fracture risk in this high-risk group.

Use of Proton Pump Inhibitors and Risk of Fracture in Adults: A Review of Literature

Proton pump inhibitors (PPIs) are commonly used medications for various gastrointestinal disorders and are reported to be associated with bone fractures. A literature review was performed, which showed PPI to be associated with a shorter time to first fracture in adults aged 25 or older. There was an overall increased risk of fractures with PPI use in adults; however, such risk was not significantly higher in women over 80 years of age and adult patients with rheumatoid arthritis. In healthy adult males aged 18-50 years, PPI use was not associated with significant changes in calcium and bone metabolism with PPI use. The lack of increased risk among elderly women aged more than 80 and rheumatoid arthritis patients raises the possible confounding or effect modification by factors that affect the fracture risk with PPI use. We concluded that although observational studies show an increased risk of fractures with PPI use, warranting their use with caution in some patients, experimental evidence explaining the risk is still lacking.

Cost Analysis of Implementing an Exercise Program for Fall and Fracture Prevention in Older Adults on Proton Pump Inhibitor Therapy

PURPOSE

Falls have significant financial impact. Proton pump inhibitor (PPI) therapy is associated with an increased risk of falls and fractures. Exercise programs have been shown to decrease risk of falls in the elderly population and are recommended by the U.S. Preventive Services Task Force for patients over age 65 to reduce falls. Our study aimed to explore the potential financial benefit of implementing three different Centers for Disease Control and Prevention-recommended exercise-based interventions for fall prevention (Tai Chi, Stepping On, and Otago Exercise Program) in ≥65-year-old patients on PPI therapy.

METHODS

A Markov model was developed to predict the financial implications of fall-related outcomes in the study population. Net cost of the intervention was deducted from the financial savings predicted for fall avoidance relative to the fall reduction conferred by the intervention. Sensitivity analysis was performed on a range of odds ratios between falling and PPI use.

RESULTS

Exercise-based interventions were found to offer financial savings when fall reduction rates exceeded 5%, irrespective of variable odds ratios between PPI use and fall rate. Hypothetical implementation of an exercise-based intervention for PPI users ≥65 years of age was estimated to result in annual fall- and fracture-related savings ranging from $10,317.35 to $18,766.28 per individual. Findings suggested an estimated annual reduction in U.S. health care costs of $18 billion to $85 billion.

CONCLUSIONS

Implementing an exercise-based fall prevention program for elderly PPI users represents a possible strategy to mitigate health care costs in the United States. Future prospective studies are recommended.

Polypharmacy Predicts Onset and Transition of Frailty, Malnutrition, and Adverse Outcomes in Peritoneal Dialysis Patient

BACKGROUND

Polypharmacy, frailty and malnutrition are known predictors of adverse outcomes in dialysis patients. Little has reported about their interaction and composite prognostic values. We aimed to describe the interaction between polypharmacy, frailty, nutrition, hospitalization, and survival in peritoneal dialysis patients.

METHODS

In this prospective cohort study, we recruited 573 peritoneal dialysis patients. Drug burden was measured by medication number and daily pill load. Frailty and nutrition were assessed by the validated Frailty Score (FQ) and Subjective Global Assessment (SGA) respectively. All patients were followed for two years. Primary outcome was all-cause mortality. Secondary outcomes were fall and fracture episodes, hospitalization, change in FQ and SGA.

RESULTS

At baseline, each patient took 7.5 ± 2.6 medications with 15.5 ± 8.5 tablets per day. Medication number, but not daily pill load predicted baseline FQ (p = 0.004) and SGA (p = 0.03). Over 2 years, there were 69 fall and 1,606 hospitalization episodes. In addition, 148 (25.8%) patients died, while FQ and SGA changed by 0.73 ± 4.23 and -0.07 ± 1.06 respectively in survivors. Medication number (hospitalization: p = 0.02, survival: p = 0.005), FQ (hospitalization: p < 0.001; survival: p = 0.01) predicted hospitalization and survival. Medication number also predicted fall episodes (p = 0.02) and frailty progression (p = 0.002). Daily pill load did not predict any of these outcomes.

CONCLUSIONS

Drug burden is high in peritoneal dialysis patients, and it carries important prognostic implication. Medication number but not pill load significantly predicted onset and progression of frailty, malnutrition, fall, hospitalization, and mortality.

Bone density status in a large population of patients with anorexia nervosa

Anorexia nervosa (AN) is associated with multiple medical complications. One of the rare permanent complications of AN is the deleterious effect that it has on a patient's bone mineral density (BMD). We report on the Dual-Energy X-ray Absorptiometry (DXA) findings of 336 consecutive patients with AN. Also, we investigated the effects of different factors on these DXA results. These factors included age, body mass index (BMI), percentage of ideal body weight (IBW), duration of illness, duration of amenorrhea, medications such as proton pump inhibitors (PPI) or selective serotonin reuptake inhibitors (SSRI), tobacco use and 25-hydroxy vitamin D levels. This study demonstrated a concerning high prevalence of reduced bone mineral density in patients with AN. Thus, the implication being that those involved in the care of patients with AN need to be cognizant of this serious complication and not be assuaged by the young age of this patient population.

The Association between Frailty and Abdominal Symptoms: A Hospital-based Cross-sectional Study

Objective The association between frailty and abdominal symptoms has not been evaluated. Methods We conducted a hospital-based, retrospective cross-sectional study of consecutive outpatients ≥65 years old at the Department of Gastroenterology, Juntendo Tokyo Koto Geriatric Medical Center from 2017 to 2019. Patients were included in the study if all of the following information was available from their medical records: patient's profile, the evaluation of osteoporosis, sarcopenia, frailty, nutritional status, findings of upper gastrointestinal endoscopy, and questionnaire results for abdominal symptoms [Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease (FSSG) and Constipation Scoring System (CSS)]. We divided the subjects into frailty and non-frailty groups and investigated the risk factors for frailty. Results Of the 313 eligible study subjects [134 men (42.8%) and 179 women (57.2%); mean age, 75.7±6.0 years; mean body mass index, 22.8±3.6 kg/m²], frailty was noted in 71 cases (22.7%). In a univariate analysis, an older age (p<0.001), female gender (p=0.010), successful eradication of Helicobacter pylori (p=0.049), proton pump inhibitor (PPI) use (p<0.001), laxative/prokinetics use (p=0.008), sarcopenia (p<0.001), osteoporosis (p<0.001), hypozincemia (p=0.002), hypoalbuminemia (p<0.001), low lymphocytes (p=0.004), a high CONUT score (p<0.001), a high FSSG score (p=0.001), and a high CSS score (p<0.001) were significantly associated with frailty. A multivariate logistic regression analysis showed that an older age [odds ratio (OR) 1.16; 95% confidence interval (CI) 1.08-1.24, p<0.001], PPI use (OR 2.42; 95% CI 1.18-4.98, p=0.016), sarcopenia (OR 7.35; 95% CI 3.30-16.40, p<0.001), hypozincemia (OR 0.96; 95% CI 0.92-0.99, p=0.027), a high FSSG score (OR 1.08; 95% CI 1.01-1.16, p=0.021), and a high CSS score (OR 1.13; 95% CI 1.03-1.23, p=0.007) were significantly associated with frailty. Conclusion Advanced age, PPI user, sarcopenia, hypozincemia, a high FSSG score, and high CSS score are associated with frailty.

Increased Risk of Bone Fractures in Hemodialysis Patients Treated with Proton Pump Inhibitors in Real World: Results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Long-term treatment with proton pump inhibitors (PPIs) is associated with an increased risk of fractures in the general population. PPIs are widely prescribed to dialysis patients but to date no study has specifically tested, by state-of-art statistical methods, the relationship between use of PPIs and fractures in this patient population. This study aimed to assess whether use of PPIs is associated with bone fractures (ie, hip fractures and fractures other than hip fractures) in a large international cohort of hemodialysis patients. We considered an observational prospective cohort of 27,097 hemodialysis patients from the Dialysis Outcomes and Practice Patterns Study (DOPPS). Data analysis was performed by the Fine and Gray method, considering the competitive risk of mortality, as well as by a cause-specific hazards Cox model with death as a censoring event and matching patients according to the prescription time. Of 27,097 hemodialysis patients, 13,283 patients (49%) were on PPI treatment. Across the follow-up period (median, 19 months), 3.8 bone fractures × 100 person-years and 1.2 hip fractures × 100 person-years occurred. In multiple Cox models, considering the competitive risk of mortality, the incidence rate of bone (subdistribution hazard ratio [SHR] 1.22; 95% CI, 1.10 to 1.36; p < 0.001) and hip fractures (SHR 1.35; 95% CI, 1.13 to 1.62; p = 0.001) was significantly higher in PPI-treated than in PPI-untreated patients. These findings also held true in multiple, cause-specific, hazards Cox models matching patients according to the prescription time (bone fractures: HR 1.47; 95% CI, 1.23 to 1.76; p < 0.001; hip fractures: HR 1.85; 95% CI, 1.37 to 2.50; p < 0.001). The use of PPIs requires caution and a careful evaluation of risks/benefits ratio in hemodialysis patients. © 2019 American Society for Bone and Mineral Research.

Effect of Gastric Acid Suppressants on Response to a Physical Activity Intervention and Major Mobility Disability in Older Adults: Results from the Lifestyle Interventions for Elders (LIFE) Study

OBJECTIVES

Proton pump inhibitors (PPIs) and histamine2 receptor antagonists (H2 RAs) are associated with pharmacologic effects that may be detrimental to mobility and response to physical activity. Mobility disability and injurious fall outcomes in PPI and H2 RA users were compared with nonusers in this secondary analysis of data from the Lifestyle Interventions for Elders (LIFE) study.

METHODS

Participants ages 70-89 years were randomized to a physical activity (PA) or successful aging intervention and evaluated by medication use. Confounders included baseline demographic characteristics, physical function, cognitive function, sleep quality, and acid reflux symptoms that were adjusted via propensity score weighting. Outcomes were incident and persistent major mobility disability (MMD and pMMD) and injurious falls. Weighted proportional hazard models evaluated independent and interaction effects of PPIs and H2 RAs.

RESULTS

No interaction was found between PPIs and H2 RAs and the PA intervention. Drug use associations were significant for H2 RAs (hazard ratio [HR] 1.74 [95% confidence interval [CI] 1.12-2.68]) and PPIs (HR 1.32 [95% CI 1.02-1.70]) compared with nonusers for pMMD. PPIs were associated with increased injurious falls compared with nonusers (HR 1.44 [95% CI 1.06-1.96]). Pooling of data from the H2 RA and PPI exposure groups showed a 26% increase in MMD (HR 1.26 [95% CI 1.07-1.48]), a 44% increase in pMMD (HR 1.44 [95% CI 1.16-1.77]), and a 48% increase in injurious falls (HR 1.48 [95% CI 1.15-1.91]) compared with nonusers. All direct comparisons between PPIs and H2 RAs were nonsignificant.

CONCLUSIONS

Compared with nonusers, participants using either PPIs or H2 RAs had an increased risk of MMD, pMMD, and injurious falls. It is not known if these effects are related to the individual pharmacology of each medication, reduced acid secretion, or the underlying disease state. Further study is required to determine causality.

Proton Pump Inhibitors and Fracture Risk: A Review of Current Evidence and Mechanisms Involved

The number of patients with gastroesophageal problems taking proton pump inhibitors (PPIs) is increasing. Several studies suggested a possible association between PPIs and fracture risk, especially hip fractures, but the relationship remains contentious. This review aimed to investigate the longitudinal studies published in the last five years on the relationship between PPIs and fracture risk. The mechanism underlying this relationship was also explored. Overall, PPIs were positively associated with elevated fracture risk in multiple studies (n = 14), although some studies reported no significant relationship (n = 4). Increased gastrin production and hypochlorhydria are the two main mechanisms that affect bone remodeling, mineral absorption, and muscle strength, contributing to increased fracture risk among PPI users. As a conclusion, there is a potential relationship between PPIs and fracture risks. Therefore, patients on long-term PPI treatment should pay attention to bone health status and consider prophylaxis to decrease fracture risk.

Reducing inappropriate prescribing for older adults with advanced frailty: A review based on a survey of practice in four countries

The management of medications in persons with frailty presents challenges. There is evidence of inappropriate prescribing and a lack of consensus among healthcare professionals on the judicious use of medications, particularly for patients with more severe frailty. This study reviews the evidence on the use of commonly prescribed pharmacological treatments in advanced frailty based on a questionnaire of prescribing practices and attitudes of healthcare professionals at different stages in their careers, in different countries. A convenience sample of those attending hospital grand rounds in Ireland, Canada and Australia/New Zealand (ANZ) were surveyed on the management of 18 medications in advanced frailty using a clinical vignette (man with severe dementia, Clinical Frailty Scale 7/9). Choices were to continue or discontinue (stop now or later) medications. In total, 298 respondents from Ireland (n = 124), Canada (n = 110), and ANZ (n = 64) completed the questionnaire, response rate 97%, including 81 consultants, 40 non-consultant hospital doctors, 134 general practitioners and 43 others (nurses, pharmacists, and medical students). Most felt that statins (88%), bisphosphonates (77%) and cholinesterase inhibitors (76%) should be discontinued. Thyroid replacement (88%), laxatives (83%) and paracetamol (81%) were most often continued. Respondents with experience in geriatric, palliative and dementia care were significantly more likely to discontinue medications. Age, gender and experience working in nursing homes did not contribute to the decision. Reflecting the current literature, there was no clear consensus on inappropriate prescribing, although respondents preferentially discontinued medications for secondary prevention. Experience significantly predicted the number and type discontinued, suggesting that education is important in reducing inappropriate prescribing for people in advanced states of frailty.

Management of cardiovascular complications in Klinefelter syndrome patients

INTRODUCTION

Klinefelter syndrome (KS), also known as 47, XXY, shows increased mortality when compared with mortality rates among the general population. Cardiovascular, hemostatic, metabolic diseases are implicated. Moreover, cardiac congenital anomalies in KS can contribute to the increase in mortality.

AREAS COVERED

In this study, we have systematically reviewed the relationships between KS and the cardiovascular system and the management of cardiovascular complication. In summary, patients with KS display increased cardiovascular risk profile, characterized by increased prevalence of metabolic alterations including dyslipidemia, diabetes mellitus (DM), and abnormalities in biomarkers of cardiovascular disease. KS subjects are characterized by subclinical abnormalities in endothelial function and in left ventricular (LV) systolic and diastolic function, which - when associated with chronotropic incompetence - may negatively influence cardiopulmonary performance. Moreover, KS patients appear to be at a higher risk for cardiovascular disease, due to thromboembolic events with high prevalence of recurrent venous ulcers, venous insufficiency, recurrent venous and arterial thromboembolism leading to deep venous thrombosis or pulmonary embolism.

EXPERT OPINION

Considering the unequivocal finding of increased mortality of KS patients, we suggest a periodic cardiovascular follow up in specialized centers with multidisciplinary care teams that comprise endocrinologists and cardiologists dedicated to KS syndrome.

Proton Pump Inhibitors and the Risk for Fracture at Specific Sites: Data Mining of the FDA Adverse Event Reporting System

Proton pump inhibitors (PPIs) are widely used to treat gastric acid-related disorders. Concerns have been raised about potential fracture risk, especially at the hip, spine and wrist. However, fracture risk at other bone sites has not been as well studied. We investigated the association between PPIs and specific fracture sites using an aggregated knowledge-enhanced database, the Food and Drug Administration Adverse Event Reporting System Data Mining Set (AERS-DM). Proportional reporting ratio (PRR) was used to detect statistically significant associations (signals) between PPIs and fractures. We analyzed both high level terms (HLT) and preferred terms (PT) for fracture sites, defined by MedDRA (Medical Dictionary for Regulatory Activities). Of PPI users reporting fractures, the mean age was 65.3 years and the female to male ratio was 3.4:1. Results revealed signals at multiple HLT and PT fracture sites, consistent for both sexes. These included fracture sites with predominant trabecular bone, not previously reported as being associated with PPIs, such as 'rib fractures', where signals were detected for overall PPIs as well as for each of 5 generic ingredients (insufficient data for dexlansoprazole). Based on data mining from AERS-DM, PPI use appears to be associated with an increased risk for fractures at multiple sites.

Mind the (treatment) gap: a global perspective on current and future strategies for prevention of fragility fractures

This narrative review considers the key challenges facing healthcare professionals and policymakers responsible for providing care to populations in relation to bone health. These challenges broadly fall into four distinct themes: (1) case finding and management of individuals at high risk of fracture, (2) public awareness of osteoporosis and fragility fractures, (3) reimbursement and health system policy and (4) epidemiology of fracture in the developing world. Findings from cohort studies, randomised controlled trials, systematic reviews and meta-analyses, in addition to current clinical guidelines, position papers and national and international audits, are summarised, with the intention of providing a prioritised approach to delivery of optimal bone health for all. Systematic approaches to case-finding individuals who are at high risk of sustaining fragility fractures are described. These include strategies and models of care intended to improve case finding for individuals who have sustained fragility fractures, those undergoing treatment with medicines which have an adverse effect on bone health and people who have diseases, whereby bone loss and, consequently, fragility fractures are a common comorbidity. Approaches to deliver primary fracture prevention in a clinically effective and cost-effective manner are also explored. Public awareness of osteoporosis is low worldwide. If older people are to be more pro-active in the management of their bone health, that needs to change. Effective disease awareness campaigns have been implemented in some countries but need to be undertaken in many more. A major need exists to improve awareness of the risk that osteoporosis poses to individuals who have initiated treatment, with the intention of improving adherence in the long term. A multisector effort is also required to support patients and their clinicians to have meaningful discussions concerning the risk-benefit ratio of osteoporosis treatment. With regard to prioritisation of fragility fracture prevention in national policy, there is much to be done. In the developing world, robust epidemiological estimates of fracture incidence are required to inform policy development. As the aging of the baby boomer generation is upon us, this review provides a comprehensive analysis of how bone health can be improved worldwide for all.

Effective and safe proton pump inhibitor therapy in acid-related diseases - A position paper addressing benefits and potential harms of acid suppression

BACKGROUND

The introduction of proton pump inhibitors (PPIs) into clinical practice has revolutionized the management of acid-related diseases. Studies in primary care and emergency settings suggest that PPIs are frequently prescribed for inappropriate indications or for indications where their use offers little benefit. Inappropriate PPI use is a matter of great concern, especially in the elderly, who are often affected by multiple comorbidities and are taking multiple medications, and are thus at an increased risk of long-term PPI-related adverse outcomes as well as drug-to-drug interactions. Herein, we aim to review the current literature on PPI use and develop a position paper addressing the benefits and potential harms of acid suppression with the purpose of providing evidence-based guidelines on the appropriate use of these medications.

METHODS

The topics, identified by a Scientific Committee, were assigned to experts selected by three Italian Scientific Societies, who independently performed a systematic search of the relevant literature using Medline/PubMed, Embase, and the Cochrane databases. Search outputs were distilled, paying more attention to systematic reviews and meta-analyses (where available) representing the best evidence. The draft prepared on each topic was circulated amongst all the members of the Scientific Committee. Each expert then provided her/his input to the writing, suggesting changes and the inclusion of new material and/or additional relevant references. The global recommendations were then thoroughly discussed in a specific meeting, refined with regard to both content and wording, and approved to obtain a summary of current evidence.

RESULTS

Twenty-five years after their introduction into clinical practice, PPIs remain the mainstay of the treatment of acid-related diseases, where their use in gastroesophageal reflux disease, eosinophilic esophagitis, Helicobacter pylori infection, peptic ulcer disease and bleeding as well as, and Zollinger-Ellison syndrome is appropriate. Prevention of gastroduodenal mucosal lesions (and symptoms) in patients taking non-steroidal anti-inflammatory drugs (NSAIDs) or antiplatelet therapies and carrying gastrointestinal risk factors also represents an appropriate indication. On the contrary, steroid use does not need any gastroprotection, unless combined with NSAID therapy. In dyspeptic patients with persisting symptoms, despite successful H. pylori eradication, short-term PPI treatment could be attempted. Finally, addition of PPIs to pancreatic enzyme replacement therapy in patients with refractory steatorrhea may be worthwhile.

CONCLUSIONS

Overall, PPIs are irreplaceable drugs in the management of acid-related diseases. However, PPI treatment, as any kind of drug therapy, is not without risk of adverse effects. The overall benefits of therapy and improvement in quality of life significantly outweigh potential harms in most patients, but those without clear clinical indication are only exposed to the risks of PPI prescription. Adhering with evidence-based guidelines represents the only rational approach to effective and safe PPI therapy. Please see related Commentary: doi: 10.1186/s12916-016-0724-1 .

Proton Pump Inhibitor Use and Magnesium Concentrations in Hemodialysis Patients: A Cross-Sectional Study

Magnesium concentration is a proven predictor of mortality in hemodialysis patients. Recent reports have indicated that proton pump inhibitor (PPI) use affects serum magnesium levels, however few studies have investigated the relationship between PPI use and magnesium levels in hemodialysis patients. This study aimed to clarify the association between PPI use and serum magnesium levels in hemodialysis patients. We designed this cross sectional study and included 1189 hemodialysis patients in stable condition. Associations between PPI and magnesium-related factors, as well as other possible confounders, were evaluated using a multiple regression model. We defined hypomagnesemia as a value < 2.0 mg/dL, and created comparable logistic regression models to assess the association between PPI use and hypomagnesemia. PPI use is associated with a significantly lower mean serum magnesium level than histamine 2 (H2) receptor antagonists or no acid-suppressive medications (mean [SD] PPI: 2.52 [0.45] mg/dL; H2 receptor antagonist: 2.68 [0.41] mg/dL; no acid suppressive medications: 2.68 [0.46] mg/dL; P = 0.001). Hypomagnesemia remained significantly associated with PPI (adjusted OR, OR: 2.05; 95% CI: 1.14–3.69; P = 0.017). PPI use is associated with an increased risk of hypomagnesemia in hemodialysis patients. Future prospective studies are needed to explore magnesium replacement in PPI users on hemodialysis.

Molecular modelling studies on 2-substituted octahydropyrazinopyridoindoles for histamine H2 receptor antagonism

The human histamine H2 receptor (hH2HR) is a G-protein coupled receptor protein with seven transmembrane (TM)-spanning helices primarily involved in regulation of gastric acid secretion. Antagonists targeting hH2HR are useful in the treatment of hyperacidic conditions such as peptic ulcers, gastresophageal reflux disease and gastrointestinal bleeding. We have previously reported the antagonism of 2-substituted pyrazinopyridoindoles at the human histamine H1 receptor and mode of binding of these compounds at the hH1HR using in silico methods. Interestingly, some of the compounds in the series also showed promising activity towards hH2HR that prompted us to investigate the mode of binding of these compounds at hH2HR. In the absence of the crystal structure of hH2HR a homology model has been constructed using multiple sequence alignment, using the X-ray crystal structures of Turkey β1-adrenergic receptor (tβ1AR), Human histamine H1 receptor (hH1HR), Human β2-adrenergic receptor (hβ2AR) and Human D3 dopamine receptor (hD3R). The important residues for binding were depicted in TMIII, TMV, TMVI and TMVII by the homology modelled hH2HR for 2-substituted pyrazinopyridoindoles. A comparative study for deducing the selectivity regarding the binding towards hH1HR and hH2HR has been carried out, which may be useful in designing of selective hH1HR/hH2HR antagonists in these classes of compounds.