Risk factors for the development of hypermagnesemia in patients prescribed magnesium oxide: a retrospective cohort study

Current Treatment Practices for Adult Patients with Constipation in Japan

BACKGROUND

The prevalence of constipation in Japan is estimated to be 2-5%. Constipation is a disease found in older adults. In particular, Japan is an aging society, with 65% of men and 80.5% of women aged 65 years or older accounting for the majority of its population. Chronic constipation may be associated with survival, cardiovascular events, decreased quality of life, and death. This study summarizes the recent findings regarding constipation treatment practice in Japan.

SUMMARY

Until recently, the diagnosis of constipation was mainly based on medical interviews; however, with the recent development of handheld ultrasound devices, both physicians and nurses can easily and objectively diagnose fecal retention. Magnesium oxide and stimulant laxatives have been the mainstay treatments; however, since 2012, more than five new drugs for treating constipation have become available in Japan.

KEY MESSAGES

Magnesium oxide is less effective in patients who use acid-secretion inhibitors and patients who have undergone total gastrectomy and should be cared for hypermagnesemia. In addition, regular use of stimulant laxatives may lead to colonic inertia and decreased bowel movements; therefore, they should be used only occasionally. The following is an overview of the different uses of conventional and newer laxatives for treating constipation.

Exploratory Study of Pharmacists' Monitoring Methods Based on Left Ventricular Function for Hypermagnesemia by Magnesium Oxide in Heart Failure

Serum magnesium (Mg) monitoring in patients with heart failure (HF) receiving magnesium oxide (MgO) is not adequately performed. Furthermore, the relationship between left ventricular function (LVF) and hypermagnesemia in HF is unknown. Here, we investigated the efficacy of serum Mg monitoring by protocol-based pharmaceutical management (PBPM) and the effect of LVF on hypermagnesemia. This protocol is for patients with an estimated glomerular filtration rate of <45 mL/min, receiving MgO, and admitted to the cardiology unit. The pharmacist includes the measurement of Mg when a blood test is ordered for a patient by their physician. Rates of serum Mg measurement and hypermagnesemia detection were compared at 2 years pre-PBPM (n = 88) and at 2 years post-PBPM (n = 55). LVF parameters and reported factors for hypermagnesemia were selected as explanatory factors on multivariate logistic regression. The measurement rate of serum Mg concentration significantly increased from 19.3% pre-PBPM to 80.0% post-PBPM (P < .001). The detection rate of hypermagnesemia also increased from 3.4% to 27.3%, respectively (P < .001). Our results suggest that serum Mg monitoring by PBPM may contribute to the early detection of hypermagnesemia and prevent its progression in HF. According to logistic regression, the adjusted odds ratio for hypermagnesemia with an exacerbation of HF was 9.57 (95% confidence interval: 1.594-57.477, P = .014), and the E/e' > 15, an index of reduced left ventricular diastolic capacity, was 6.46 (95% confidence interval: 1.291-32.364, P = .023). We propose that serum Mg monitoring should be performed during exacerbations of HF in patients with left ventricular diastolic dysfunction, with a pharmacist's assistance.

Association between hypomagnesemia and coagulopathy in sepsis: a retrospective observational study

BACKGROUND

Hypomagnesemia reportedly has significant associations with poor clinical outcomes such as increased mortality and septic shock in patients with sepsis. Although the mechanism underlying these outcomes mostly remains unclear, some experimental data suggest that magnesium deficiency could potentiate coagulation activation in sepsis. However, in sepsis, the association between serum magnesium levels and coagulopathy, including disseminated intravascular coagulation (DIC), remains unknown. Thus, we aimed to investigate the relationship between serum magnesium levels and coagulation status and the association between hypomagnesemia and DIC in patients with sepsis.

METHODS

This retrospective observational study was conducted at the intensive care unit (ICU) of a university hospital from June 2011 to December 2017. Patients older than 19 years who met the Sepsis-3 definition were included. We categorized patients into three groups according to their serum magnesium levels: hypomagnesemia (< 1.6 mg/dL), normal serum magnesium level (1.6-2.4 mg/dL), and hypermagnesemia (> 2.4 mg/dL). We investigated the association between serum magnesium levels and overt DIC at the time of ICU admission according to the criteria of the International Society on Thrombosis and Haemostasis.

RESULTS

Among 753 patients included in this study, 181 had DIC, 105 had hypomagnesemia, 552 had normal serum magnesium levels, and 96 had hypermagnesemia. Patients with hypomagnesemia had a more activated coagulation status indicated by lower platelet counts, lower fibrinogen levels, higher prothrombin time-international normalized ratios, higher thrombin-antithrombin complex, and more frequent DIC than those with normal serum magnesium levels and hypermagnesemia (DIC: 41.9% vs. 20.6% vs. 24.0%, P < 0.001). The coagulation status in patients with hypomagnesemia was more augmented toward suppressed fibrinolysis than that in patients with normal serum magnesium levels and hypermagnesemia. Multivariate logistic regression revealed that hypomagnesemia was independently associated with DIC (odds ratio, 1.69; 95% confidence interval, 1.00-2.84; P = 0.048) after adjusting for several confounding variables.

CONCLUSIONS

Patients with hypomagnesemia had a significantly activated coagulation status and suppressed fibrinolysis. Hypomagnesemia was independently associated with DIC in patients with sepsis. Therefore, the treatment of hypomagnesemia may be a potential therapeutic strategy for the treatment of coagulopathy in sepsis.

Safety and Efficacy of Elobixibat, an Ileal Bile Acid Transporter Inhibitor, in Elderly Patients With Chronic Idiopathic Constipation According to Administration Time: Interim Analysis of Post-marketing Surveillance

Background/Aims

Elobixibat, an ileal bile acid transporter (apical sodium-dependent bile acid transporter) inhibitor, was recently launched in Japan for the treatment of chronic idiopathic constipation. We conducted an interim analysis of post-marketing surveillance to evaluate the safety and efficacy of elobixibat in elderly patients with chronic constipation and compared the efficacy according to administration time.

Methods

Safety and efficacy outcomes were evaluated through patient interviews for 4 weeks.

Results

Adverse drug reactions (ADRs) were observed in 5.24% of the 1049 patients analyzed; diarrhea (2.19%) and abdominal pain (1.81%) were the most common. A serious ADR of death was reported in one patient (0.10%). The incidence of ADRs in the ≥ 65-year old or ≥ 75-year-old subpopulation was similar to that in the total patient population. Mean bowel movements per week significantly increased from 2.9 ± 2.5 at baseline to 5.0 ± 3.1 (P < 0.001) at Week 2 and 5.3 ± 2.6 (P < 0.001) at Week 4. The mean Bristol Stool Form Scale score significantly increased from 2.3 ± 1.4 at baseline to 3.8 ± 1.3 (P < 0.001) at Week 2 and 3.9 ± 1.1 at Week 4 (P < 0.001). Bowel movements significantly increased in the elderly population and subpopulations receiving elobixibat before breakfast, lunch, or dinner. The median time to bowel movement was 5 hours.

Conclusion

The results suggested that elobixibat was well-tolerated and efficacious in elderly patients with chronic constipation and can be administered before any meals.

Magnesium Oxide in Constipation

Magnesium oxide has been widely used as a laxative for many years in East Asia, yet its prescription has largely been based on empirical knowledge. In recent years, several new laxatives have been developed, which has led to a resurgence in interest and increased scientific evidence surrounding the use of magnesium oxide, which is convenient to administer, of low cost, and safe. Despite these advantages, emerging clinical evidence indicates that the use of magnesium oxide should take account of the most appropriate dose, the serum concentration, drug-drug interactions, and the potential for side effects, especially in the elderly and in patients with renal impairment. The aim of this review is to evaluate the evidence base for the clinical use of magnesium oxide for treating constipation and provide a pragmatic guide to its advantages and disadvantages.

The Combined Effects of Magnesium Oxide and Inulin on Intestinal Microbiota and Cecal Short-Chain Fatty Acids

Constipation is a common condition that occurs in many people worldwide. While magnesium oxide (MgO) is often used as the first-line drug for chronic constipation in Japan, dietary fiber intake is also recommended. Dietary fiber is fermented by microbiota to produce short-chain fatty acids (SCFAs). SCFAs are involved in regulating systemic physiological functions and circadian rhythm. We examined the effect of combining MgO and the water-soluble dietary fiber, inulin, on cecal SCFA concentration and microbiota in mice. We also examined the MgO administration timing effect on cecal SCFAs. The cecal SCFA concentrations were measured by gas chromatography, and the microbiota was determined using next-generation sequencing. Inulin intake decreased cecal pH and increased cecal SCFA concentrations while combining MgO increased the cecal pH lowered by inulin and decreased the cecal SCFA concentrations elevated by inulin. When inulin and MgO were combined, significant changes in the microbiota composition were observed compared with inulin alone. The MgO effect on the cecal acetic acid concentration was less when administered at ZT12 than at ZT0. In conclusion, this study suggests that MgO affects cecal SCFA and microbiota during inulin feeding, and the effect on acetic acid concentration is time-dependent.

Real-World Comparison of Elobixibat and Lubiprostone Treatment in Patients with Chronic Constipation: A Propensity Score-Matched Analysis

INTRODUCTION

Elobixibat is a new laxative, but its efficacy and adverse events (AEs) are insufficiently examined compared with those of other laxatives. Hence, by propensity score (PS) matching, we compared the effects and AEs between elobixibat and lubiprostone.

METHODS

We retrospectively analyzed 1,887 Japanese patients with chronic constipation (CC) treated at our hospital between October 2013 and April 2020. Enrolled patients were divided into three treatment groups, namely, elobixibat (10 mg daily) (E10 group, n = 293), lubiprostone (24 μg daily) (L24 group, n = 772), and lubiprostone (48 μg daily) (L48 group, n = 822), as their first treatment. We then investigated the changes on the weekly average number of spontaneous bowel movements, stool consistency scores (SCSs), and AEs starting from the baseline until the end of the 2-week treatment. To adjust for patients' background, we performed one-to-one nearest neighbor matching without replacement between elobixibat- and lubiprostone-treated patients according to the individual estimated PSs.

RESULTS

After treatment, for SCSs, both the L24 and L48 groups significantly improved compared with the E10 group (p < 0.05), but their stools were soft (Bristol Stool Form Scale: 4.8). Notably, the E10 group had less frequent AEs than the L24 group (26 [9.0%] vs. 43 [14.8%], p = 0.03). Particularly, nausea was significantly less in the E10 group than that in the L48 group (2 [0.7%] vs. 7 [2.4%], p = 0.01).

CONCLUSION

Elobixibat is a beneficial drug for patients with mildly symptomatic CC and is safe to use, given its few AEs.

Variations in Magnesium Concentration Are Associated with Increased Mortality: Study in an Unselected Population of Hospitalized Patients

Dysmagnesemia is a serious disturbance of microelement homeostasis. The aim of this study was to analyze the distribution of serum magnesium concentrations in hospitalized patients according to gender, age, and result of hospitalization. The study was conducted from February 2018 to January 2019 at the Central Clinical Hospital in Warsaw. Laboratory test results from 20,438 patients were included in this retrospective analysis. When a lower reference value 0.65 mmol/L was applied, hypermagnesemia occurred in 196 patients (1%), hypomagnesemia in 1505 patients (7%), and normomagnesemia in 18,711 patients (92%). At a lower reference value of 0.75 mmol/L, hypomagnesemia was found in 25% and normomagnesemia in 74% of patients. At a lower reference value of 0.85 mmol/L, hypomagnesemia was found in 60% and normomagnesemia in 39% of patients. Either hypo- or hyper-magnesemia was associated with increased risk of in-hospital mortality. This risk is the highest in patients with hypermagnesemia (40.1% of deaths), but also increases inversely with magnesium concentration below 0.85 mmol/L. Serum magnesium concentration was not gender-dependent, and there was a slight positive correlation with age (p < 0.0001, r = 0.07). Large fluctuations in serum magnesium level were associated with increased mortality (p = 0.0017). The results indicate that dysmagnesemia is associated with severe diseases and generally severe conditions. To avoid misdiagnosis, an increase of a lower cut-off for serum magnesium concentration to at least 0.75 mmol/L is suggested.

Appropriate Use of Laxatives in the Older Person

Constipation is a common condition, affecting up to half of all older adults during their lifetime. Untreated constipation has significant impacts, decreasing quality of life and potentially leading to urinary and/or faecal incontinence, faecal impaction and, in severe cases, hospitalisation. The increased constipation prevalence among older populations is multifactorial, with a number of age-related factors contributing to the rise in prevalence with aging. Laxatives are the mainstay of constipation management and are commonly used among older populations for both treatment and prevention of constipation. A range of laxative types including bulk forming agents, softeners and emollients, osmotic agents, stimulants, and the newer prokinetic and secretory agents are available. Despite laxatives being freely available without prescription in many countries and commonly used by older individuals, evidence regarding the effectiveness or safety of most laxatives in older populations is lacking. Additionally, age-related changes increase the risk of adverse effects associated with laxatives, such as electrolyte disturbances, among older persons. Caution must be taken when extrapolating recommendations for general adult populations to older populations. Laxative choice for older individuals should be tailored after careful assessment and consideration of comorbid conditions, concomitant medications and the potential for adverse effects.

Clinical features of hypermagnesemia in patients with functional constipation taking daily magnesium oxide

Although magnesium oxide is widely used as a laxative, alterations in serum magnesium concentrations among patients taking daily magnesium oxide have not been clarified. The present retrospective, cross-sectional study investigated the risk factors for hypermagnesemia in patients taking daily oral magnesium oxide. Of 2,176 patients administered daily magnesium oxide, 193 (8.9%) underwent assays of serum magnesium concentrations and were evaluated. High serum magnesium concentration and hypermagnesemia were defined as serum magnesium concentrations ≥2.5 mg/dl and ≥3.0 mg/dl, respectively. Of the 193 patients taking daily magnesium oxide, 32 (16.6%) had high serum magnesium concentration and 10 (5.2%) had hypermagnesemia. Factors associated with hypermagnesemia included chronic kidney disease (CKD) grade 4 (p = 0.014) and magnesium oxide dosage (p = 0.009). Factors associated with high serum magnesium concentration included magnesium oxide dosage >1,000 mg/day (p = 0.004), CKD grades 4 (p = 0.000) and concomitant use of stimulant laxatives (p = 0.035). Age, however, was not associated with hypermagnesemia or high serum magnesium concentration. In conclusion, renal function and magnesium oxide dosage, but not age, were associated with hypermagnesemia and high serum magnesium concentration in patients with functional constipation taking daily magnesium oxide.