Proton pump inhibitor-associated hypomagnesemia: what do FDA data tell us?

Review article: The nutritional and pharmacological consequences of obesity surgery

BACKGROUND

Obesity surgery is acknowledged as a highly effective therapy for morbidly obese patients. Beneficial short-term effects on common comorbidities are practically undisputed, but a growing data pool from long-term follow-up reveals increasing evidence of potentially severe nutritional and pharmacological consequences.

AIMS

To assess the prevalence, causes and symptoms of complications after obesity surgery, to elucidate and compare therapy recommendations for macro- and micronutrient deficiencies, and to explore surgically-induced effects on drug absorption and bioavailability, discussing ramifications for long-term therapy and prophylaxis.

METHODS

PubMed, Embase and MEDLINE were searched using terms including, but not limited to, bariatric surgery, gastric bypass, obesity surgery and Roux-en-Y, coupled with secondary search terms, e.g. anaemia, micronutrients, vitamin deficiency, bacterial overgrowth, drug absorption, pharmacokinetics, undernutrition. All studies in English, French or German published January 1980 through March 2014 were included.

RESULTS

Macro- and micronutrient deficiencies are common after obesity surgery. The most critical, depending on surgical technique, are hypoalbuminemia (3-18%) and deficiencies of vitamins B1 (≤49%), B12 (19-35%) and D (25-73%), iron (17-45%) and zinc (12-91%). Many drugs commonly administered to obese patients (e.g. anti-depressants, anti-microbials, metformin) are subject to post-operative and/or PPI-associated changes affecting bioavailability and absorption.

CONCLUSIONS

Complications are associated with pre-operative and/or post-operative malnutrition or procedure-related changes in intake, absorption and drug bioavailability. The high prevalence of nutrient deficiencies after obesity surgery makes life-long nutritional monitoring and supplementation essential. Post-operative changes to drug absorption and bioavailability in bariatric patients cast doubt on the validity of standard drug dosage and administration recommendations.

Proton pump inhibitors and hospitalization with hypomagnesemia: a population-based case-control study

BACKGROUND

Some evidence suggests that proton pump inhibitors (PPIs) are an under-appreciated risk factor for hypomagnesemia. Whether hospitalization with hypomagnesemia is associated with use of PPIs is unknown.

METHODS AND FINDINGS

We conducted a population-based case-control study of multiple health care databases in Ontario, Canada, from April 2002 to March 2012. Patients who were enrolled as cases were Ontarians aged 66 years or older hospitalized with hypomagnesemia. For each individual enrolled as a case, we identified up to four individuals as controls matched on age, sex, kidney disease, and use of various diuretic classes. Exposure to PPIs was categorized according to the most proximate prescription prior to the index date as current (within 90 days), recent (within 91 to 180 days), or remote (within 181 to 365 days). We used conditional logistic regression to estimate the odds ratio for the association of outpatient PPI use and hospitalization with hypomagnesemia. To test the specificity of our findings we examined use of histamine H2 receptor antagonists, drugs with no causal link to hypomagnesemia. We studied 366 patients hospitalized with hypomagnesemia and 1,464 matched controls. Current PPI use was associated with a 43% increased risk of hypomagnesemia (adjusted odds ratio, 1.43; 95% CI 1.06-1.93). In a stratified analysis, the risk was particularly increased among patients receiving diuretics, (adjusted odds ratio, 1.73; 95% CI 1.11-2.70) and not significant among patients not receiving diuretics (adjusted odds ratio, 1.25; 95% CI 0.81-1.91). We estimate that one excess hospitalization with hypomagnesemia will occur among 76,591 outpatients treated with a PPI for 90 days. Hospitalization with hypomagnesemia was not associated with the use of histamine H2 receptor antagonists (adjusted odds ratio 1.06; 95% CI 0.54-2.06). Limitations of this study include a lack of access to serum magnesium levels, uncertainty regarding diagnostic coding of hypomagnesemia, and generalizability of our findings to younger patients.

CONCLUSIONS

PPIs are associated with a small increased risk of hospitalization with hypomagnesemia among patients also receiving diuretics. Physicians should be aware of this association, particularly for patients with hypomagnesemia. Please see later in the article for the Editors' Summary.

Hypomagnesaemia associated with long-term use of proton pump inhibitors

Hypomagnesaemia and associated hypocalcaemia and hypoparathyroidism have been increasingly recognised as rare long-term side-effects of proton pump inhibitors (PPIs). The PPIs may inhibit active magnesium (Mg) absorption by interfering with transcellular transient receptor potential melastatin-6 and -7 (TRPM 6 and 7) channels. More recent cell culture studies have suggested concomitant inhibition of passive Mg absorption by omeprazole. After being treated with a range of PPIs, the four patients in our case series developed hypomagnesaemia, which responded to withdrawal of therapy and initiation of Mg replacement. Their clinical course and management demonstrate key aspects of hypomagnesaemia associated with long-term use of PPIs.

Strategies for prevention of re-bleeding after NSAIDs-related ulcers

AIM: To compare the therapeutic efficacy and safety of teprenone combined with short- versus long-term use of omeprazole in the prevention of re-bleeding after endoscopic hemostasis for NSAIDs-related ulcers.

METHODS: Patients with NSAIDs-related ulcers who underwent Monteggia liquid spraying for bleeding were randomly divided into four groups: a teprenone group (n = 28), an omeprazole group (n = 33), a short-term combination group (n = 31), and a long-term combination group (n = 35). The incidences of re-bleeding and adverse reactions occurring during the periods of 0-13, 14-26, 0-26 and 27-52 wk were compared among the four groups.

RESULTS: The rate of re-bleeding occurring between 0 and 13 wk was significantly higher in the teprenone group than in the other groups (all P < 0.05), and the differences were not statistically significant between the other three groups (all P > 0.05). During the periods between 14 and 26 weeks and between 27 and 52 wk, there were no statistically significant differences in the rates of re-bleeding between the four groups (all P > 0.05). The incidences of adverse reactions showed no significant differences between the four groups during the period of the first 26 weeks (all P > 0.05) or between the omeprazole group and long-term combination group during the period between 27 and 52 wk (P > 0.05), but were significantly higher in the omeprazole group and long-term combination group than in the short-term combination group (both P < 0.05).

CONCLUSION: Teprenone in combination with short-term use of omeprazole has comparable efficacy to long-term use of omeprazole but is associated with significantly less adverse reactions in preventing the occurrence of re-bleeding after NSAIDs-related ulcers.