New once daily mesalamine formulations may improve adherence to medication usage.Response to Asacol and other forms of 5-aminosalicyclic acid(5-ASA)is better correlated with tissue concentrations and best predicted by...New once daily mesalamine formulations may improve adherence to medication usage.Response to Asacol and other forms of 5-aminosalicyclic acid(5-ASA)is better correlated with tissue concentrations and best predicted by concentrations of the drug within the lumen of the colon.Our group used computer simulation to predict colonic 5-ASA levels after Asacol administration.In our study,the model simulated Asacol distribution in the healthy colon,and during quiescent and active ulcerative colitis.An Asacol dosage of 800 mg,threetimes a day,was compared to 2400 mg given once a day.Under ideal conditions,the predicted maximum drug in the total colon and individual colonic segments over 100 d differed by less than 3%between single and multiple doses.Despite changes in motility and defection rates,the predicted maximum and average 5-ASA concentrations in the total colon and individual colonic segments differed by less than 10%between dosing regimens.Asymmetric distribution of 5-ASA in the colon was influenced by frequency of bowel movements and colonic transit rate.In active colitis,sigmoid 5-ASA concentration becomes negligible.Our model supports once daily administration of Asacol as standard treatment for ulcerative colitis.展开更多
BACKGROUND Enteric-coated medications are supposed to pass intact through the gastric environment and to release the drug content into the small intestine or the colon.Before dissolution of the enteric coating,they ma...BACKGROUND Enteric-coated medications are supposed to pass intact through the gastric environment and to release the drug content into the small intestine or the colon.Before dissolution of the enteric coating,they may appear hyperdense on computed tomography(CT).Unfortunately,few reports have been published on this topic so far.In this case report,the hyperdense appearance on contrastenhanced CT of an enteric-coated mesalamine tablet was initially misinterpreted as a jejunal gastrointestinal stromal tumor(GIST).CASE SUMMARY An asymptomatic 81-year-old male patient,who had undergone laparoscopic right nephrectomy four years earlier for stage 1 renal carcinoma,was diagnosed with a jejunal GIST at the 4-year follow-up thoraco-abdominal CT scan.He was referred to our hub hospital for gastroenterological evaluation,and subsequently underwent 18-fluorodeoxyglucose positron emission tomography,abdominal magnetic resonance imaging,and video capsule endoscopy.None of these examinations detected any lesion of the small intestine.After reviewing all the CT images in a multidisciplinary setting,the panel estimated that the hyperdense jejunal image was consistent with a tablet rather than a GIST.The tablet was an 800 mg delayed-release enteric-coated oral mesalamine tablet(Asacol®),which had been prescribed for non-specific colitis,while not informing the hospital physicians.CONCLUSION Delayed-release oral mesalamine(Asacol®),like other enteric-coated medications,can appear as a hyperdense image on a CT scan,mimicking a small intestinal GIST.Therefore,adetailed knowledge of the patients’medications and a multidisciplinary review of the images areessential.展开更多
文摘New once daily mesalamine formulations may improve adherence to medication usage.Response to Asacol and other forms of 5-aminosalicyclic acid(5-ASA)is better correlated with tissue concentrations and best predicted by concentrations of the drug within the lumen of the colon.Our group used computer simulation to predict colonic 5-ASA levels after Asacol administration.In our study,the model simulated Asacol distribution in the healthy colon,and during quiescent and active ulcerative colitis.An Asacol dosage of 800 mg,threetimes a day,was compared to 2400 mg given once a day.Under ideal conditions,the predicted maximum drug in the total colon and individual colonic segments over 100 d differed by less than 3%between single and multiple doses.Despite changes in motility and defection rates,the predicted maximum and average 5-ASA concentrations in the total colon and individual colonic segments differed by less than 10%between dosing regimens.Asymmetric distribution of 5-ASA in the colon was influenced by frequency of bowel movements and colonic transit rate.In active colitis,sigmoid 5-ASA concentration becomes negligible.Our model supports once daily administration of Asacol as standard treatment for ulcerative colitis.
文摘BACKGROUND Enteric-coated medications are supposed to pass intact through the gastric environment and to release the drug content into the small intestine or the colon.Before dissolution of the enteric coating,they may appear hyperdense on computed tomography(CT).Unfortunately,few reports have been published on this topic so far.In this case report,the hyperdense appearance on contrastenhanced CT of an enteric-coated mesalamine tablet was initially misinterpreted as a jejunal gastrointestinal stromal tumor(GIST).CASE SUMMARY An asymptomatic 81-year-old male patient,who had undergone laparoscopic right nephrectomy four years earlier for stage 1 renal carcinoma,was diagnosed with a jejunal GIST at the 4-year follow-up thoraco-abdominal CT scan.He was referred to our hub hospital for gastroenterological evaluation,and subsequently underwent 18-fluorodeoxyglucose positron emission tomography,abdominal magnetic resonance imaging,and video capsule endoscopy.None of these examinations detected any lesion of the small intestine.After reviewing all the CT images in a multidisciplinary setting,the panel estimated that the hyperdense jejunal image was consistent with a tablet rather than a GIST.The tablet was an 800 mg delayed-release enteric-coated oral mesalamine tablet(Asacol®),which had been prescribed for non-specific colitis,while not informing the hospital physicians.CONCLUSION Delayed-release oral mesalamine(Asacol®),like other enteric-coated medications,can appear as a hyperdense image on a CT scan,mimicking a small intestinal GIST.Therefore,adetailed knowledge of the patients’medications and a multidisciplinary review of the images areessential.
