Metoprolol diarrhea
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Metoprolol and Diarrhea: Understanding the Connection
Metoprolol Absorption in the Gastrointestinal Tract
Metoprolol, a beta-adrenoceptor blocker, is primarily absorbed in the small intestine. Studies have shown that metoprolol is not absorbed in the stomach but begins its absorption process in the duodenum, with approximately 60% of the drug being absorbed from this segment. Further absorption occurs in the jejunum, where about 50% of the drug leaving the duodenum is absorbed . This absorption process is consistent throughout the small intestine, including the ileum, indicating a first-order kinetic process .
Metoprolol and Gut Motility
Research indicates that metoprolol does not affect gut motility. This was observed in studies where metoprolol was perfused in the jejunum and ileum, showing no significant impact on the movement of the gastrointestinal tract . This suggests that any gastrointestinal side effects, such as diarrhea, are unlikely to be due to changes in gut motility caused by metoprolol.
Hepatic Metabolism and Excretion
Metoprolol is primarily metabolized by the liver, with less than 5% of an oral dose being excreted unchanged in the urine . In patients with hepatic cirrhosis, the pharmacokinetics of metoprolol are altered, leading to higher systemic availability and prolonged elimination half-life . However, these changes are related to liver function and do not directly explain gastrointestinal symptoms like diarrhea.
Conclusion
While metoprolol is absorbed in the small intestine and does not affect gut motility, its primary metabolism occurs in the liver. The available research does not directly link metoprolol to causing diarrhea. Any gastrointestinal side effects experienced may be due to individual patient responses or other underlying conditions rather than the direct action of metoprolol on the gastrointestinal tract. Further research may be needed to explore any indirect mechanisms that could contribute to such side effects.
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