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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Most relevant research papers on this topic
Investigation of drug absorption from the gastrointestinal tract of man. I. Metoprolol in the stomach, duodenum and jejunum.
Metoprolol absorption in the gastrointestinal tract is mainly from the duodenum and jejunum, with delivery being the rate-limiting factor.
Investigation of drug absorption from the gastrointestinal tract of man. II. Metoprolol in the jejunum and ileum.
Metoprolol is similarly absorbed in the jejunum and ileum, with absorption rates linearly related to perfusion rates and mean concentrations, indicating a first-order kinetic process.
Pharmacokinetics of Metoprolol in Patients with Hepatic Cirrhosis
Impaired liver function does not significantly affect the pharmacokinetics of metoprolol, with total body clearance and half-life related to galactose clearance and serum bilirubin.
Metoprolol for the Prevention of Acute Exacerbations of COPD
Metoprolol treatment for moderate or severe COPD patients without established indications showed similar time to first exacerbation but more hospitalization for exacerbation.
Use of metoprolol in dogs with acquired cardiac disease.
Metoprolol is well-tolerated in most dogs with naturally occurring dilated cardiomyopathy or endocardiosis, but further studies are needed to determine its benefits and side effects.
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