Effect of proton pump inhibitors on the development of hypomagnesemia induced by panitumumab.

Panitumumab, a therapeutic agent for unresectable advanced/recurrent colorectal cancer, is a human IgG2 monoclonal antibody that binds to and inhibits the activity of the epidermal growth factor receptor (EGFR). The onset of hypomagnesemia is a known side effect of anti-EGFR inhibitors, including panitumumab, and it is thought that inhibition of reabsorption of Mg in renal tubules is one of the causes. In addition, recent reports have shown that long-term administration of proton pump inhibitors (PPIs) reduces serum magnesium levels. Therefore, in this study, 102 patients who received oral PPIs treated with panitumumab were classified into a PPI combination group and a PPI non-combination group, and the effect of PPIs on the development of grade 2 or higher hypomagnesemia was investigated. The incidence of hypomagnesemia in the PPI combination group (46.9%, 15/32) was higher than that in the PPI non-combination group (25.7%, 18/70). A comparison of the backgrounds of the two groups of patients showed a significant difference in serum albumin levels. PPI administration was significantly associated with panitumumab-induced hypomagnesemia development when adjusted for known risk factors, serum albumin level, renal function, and oral magnesium oxide tablets in Cox proportional hazards regression analysis (hazard ratio 2.09; 95% confidence interval 1.03-4.22; P =0.040). These results indicate that detailed monitoring of serum magnesium levels is recommended for patients treated with panitumumab and co-administration of PPIs.

Headache prevalence and long working hours: the role of physical inactivity.

OBJECTIVES: Headaches and long working hours are important issues for workers. This study investigated the association between hours worked and the prevalence of headaches, and how that association varies with physical activity. STUDY DESIGN: Cross-sectional study with two-stage cluster sampling. METHODS: Using data from a nationally representative sample of households in Japan, people aged 20-65 years who worked ≥35 h/week were studied, and the cross-sectional association between the number of hours worked per week (35-45, 46-55 and >55 h/week) and the prevalence rates of headaches of different severity was evaluated. RESULTS: Of 721 workers, 307 reported experiencing at least one headache per month. Compared with working 35-45 h/week, the prevalence ratios of severe or disabling headaches among individuals working >55 h/week were 1.38 [95% confidence interval (CI) 1.06-1.78] and 1.63 (95% CI 1.09-2.43), respectively. After stratification by the level of physical activity, the prevalence ratios were greater in the low-physical-activity group: 1.56 (95% CI 1.11-2.19) for severe headaches and 2.20 (95% CI 1.31-3.68) for disabling headaches. The number of hours worked was not associated with headaches in the high-physical-activity group. CONCLUSIONS: Among workers in the general population, long working hours were associated with the prevalence of headaches, and the association may depend on a lack of physical activity.