Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Continuous enteral feedings through a nasogastric tube is the preferred route of nutritional support for malnourished patients with inadequate spontaneous oral intake. However, in patients also receiving oral medications, the use of continuous nasogastric feedings may cause malabsorption of the drugs and consequently increase the risk of an inadequate clinical response. We report a case of an elderly patient with subtherapeutic theophylline serum concentrations and recurrent bronchospasm while receiving oral theophylline and continuous enteral feedings.
Ther Drug Monit 1986
PMID:Interference with oral theophylline absorption by continuous nasogastric feedings. 382 26

A 24-year-old woman experienced grand mal seizures temporally related to cisplatin, vinblastine, and bleomycin (CVB) administration. A second episode of seizures occurred when the patient's phenytoin level was estimated to be in the range of 15 micrograms/ml. Her plasma phenytoin level at the time had dropped to 2 microgram/ml despite a recent dosage increase. To evaluate the cause of the subtherapeutic phenytoin levels, daily plasma phenytoin levels and 24-h urine collections were obtained during her next CVB cycle. Data revealed a mean phenytoin absorption of 32% (normal greater than 80%), establishing that phenytoin malabsorption occurred. The disruption of phenytoin absorption at a cellular level by CVB therapy is the proposed mechanism. Frequent monitoring of plasma phenytoin levels is recommended for patients receiving CVB.
Ther Drug Monit 1984
PMID:Impaired phenytoin bioavailability secondary to cisplatinum, vinblastine, and bleomycin. 620 33

The case of a patient with pancreatitis in whom low theophylline concentrations were observed on oral aminophylline is presented. Therapeutic theophylline concentrations were obtained with intravenous aminophylline. However, serum levels following oral doses were only 20 to 40% of those observed with intravenous administration, suggesting malabsorption. The most reasonable explanation for this was the patient's pancreatic dysfunction, since adequate absorption of oral aminophylline had been demonstrated on a previous admission not associated with pancreatis, and other possible causes of malabsorption were ruled out.
Ther Drug Monit 1981
PMID:Suspected malabsorption of aminophylline in pancreatis. 733 73

Ciprofloxacin is a fluoroquinolone antibiotic effective in the treatment of lower respiratory tract infections (LRTI). The aim of this study was to assess the pharmacokinetic appropriateness of a standard switch i.v./os regimen of ciprofloxacin (200 mg i.v. bid for 3 to 5 days followed by 500 mg os bid for 7 to 10 days) frequently used in routine clinical practice in the treatment of elderly patients with mild to moderate LRTI. The pharmacokinetic study was performed on a cohort of 17 elderly inpatients. Blood samples were collected in steady state conditions at appropriate intervals. Ciprofloxacin serum concentrations were analyzed using an HPLC method and pharmacokinetic parameters were estimated using the WinNonlin software package. The pharmacokinetic data were at least partially different from those obtained by other authors in elderly patients (lower Cmax after i.v. administration and higher CL both after i.v. and oral administration). Cmax after a 1-hour 200-mg infusion were similar to those observed during the 500 mg bid peroral regimen (2.1 +/- 0.9 mg/L vs 2.6 +/- 1.0 mg/L; p = 0.054). The absolute oral bioavailability (84.1%) allowed a total body exposure 2.1-fold greater after 500 mg bid oral administration than after 200 mg bid i.v. administration (AUC(0-tau) 11.4 +/- 4.3 mg/L x h vs 5.5 +/- 1.8 mg/L x h). The results show that in malabsorption-free elderly patients a regimen of 500 mg os bid may be considered a valid therapeutic approach from the beginning of therapy for mild to moderate LRTI caused by sensitive microorganisms (MIC < 0.1 mg/L). In fact, because the peak serum level to MIC ratio (Cmax/MIC) and the area under the inhibitory serum concentration-time curve (AUIC24 = AUC24h/MIC) are actually considered major pharmacodynamic determinants for the outcome of treatment with fluoroquinolones, this regimen could guarantee both a better pharmacokinetic exposure than the 200 mg i.v. bid regimen and a cost-effective treatment of LRTI. However, because of the great pharmacokinetic interindividual variability observed a normalized dosage per kg (3 mg/kg/12h i.v. and 8 mg/kg/12h os) should be considered, especially for body weight >90 kg and, whenever possible, TDM of AUC(0-tau) or at least of Cmax should be performed to individualize therapy in this subpopulation.
Ther Drug Monit 2000 Aug
PMID:Ciprofloxacin disposition in elderly patients with LRTI being treated with sequential therapy (200 mg intravenously twice daily followed by 500 mg per os twice daily): comparative pharmacokinetics and the role of therapeutic drug monitoring. 1094 76

Published data suggest that therapeutic drug monitoring of human immunodeficiency virus protease inhibitors would improve the management of antiretroviral therapy. The authors have developed a high-pressure liquid chromatographic assay allowing simultaneous determination of six protease inhibitors (ritonavir, saquinavir, indinavir, nelfinavir, amprenavir, and lopinavir), using carbamazepine as internal standard. Detection was based on a dual wavelength ultraviolet spectrophotometer and can be improved by the use of a photodiode array detector. Monitoring was performed 1 month after initiation of therapy or in instances of therapeutic failure, side effects, suspicion of noncompliance, drug interactions, or malabsorption. Trough concentrations were 0.15 to 13.6 mg/L for ritonavir, 0.06 to 9.7 mg/L for indinavir, 0.03 to 5.5 mg/L for saquinavir, and 0.15 to 4.15 mg/L for nelfinavir. Concentrations below the limit of quantification were observed in 63/438 (14%) of the patients. Target concentrations are not well established, and reported in vitro inhibitory concentrations may be of limited value. The authors therefore chose to compare observed concentrations with mean plasma concentrations reported in clinical trials. Observed saquinavir and indinavir concentrations were often below or close to these target concentrations, particularly when used as a single protease inhibitor. Concentration-controlled studies should now be used to select proper target concentrations for each protease inhibitor, either prescribed alone or in combination.
Ther Drug Monit 2001 Dec
PMID:Therapeutic drug monitoring of HIV protease inhibitors using high-performance liquid chromatography with ultraviolet or photodiode array detection. 1180 4

Jejunoileal bypass (JIB) is a weight loss procedure in which malabsorption is produced by connecting a short length of proximal jejunum to the distal ileum. Because 90% of the small intestine is bypassed, it may have impact on the dose-concentration response of oral cyclosporine (CsA). The authors characterized the dose-adjusted blood concentrations of CsA obtained 2 hours (C2) after oral microemulsion CsA (ME-CsA) in a liver transplant (LTx) subject with an intact JIB, as compared with those from seven LTx controls without JIB. The biliary reconstruction involved choledochocholedochostomy without external drainage in all patients. ME-CsA was administered via a nasogastric tube within 24 hours after graft reperfusion. Oral fluconazole was given prophylactically to the study subject only for 6 days after LTx. During the first week after LTx, the dose-adjusted C2 (mean +/- SD) for the study subject and for controls was 53 +/- 10 and 106 +/- 47 ng/mL, respectively (P < 0.001). The corresponding value during the period from day 7 to day 107 was 105 +/- 40 and 257 +/- 86 ng/mL, respectively (P < 0.001). Multiple linear regression revealed that dosage, days after LTx, and the presence of a JIB were all independent predictors of C2 (R2 = 0.798, P = 0.037). Lack of bile resulting in malabsorption of ME-CsA was not thought to be significant contributor to her low dose-adjusted C2 because there was no external bile drainage and a portion of terminal ileum, where most bile acid reabsorption occurred, was still available after JIB. The fact that fluconazole failed to increase the dose-adjusted C2 in the study subject supports that enteric clearance of CsA may become clinically unimportant after JIB. Therefore, the low dose-adjusted C2 is most likely explained by the reduced bowel length and associated absorptive surface area after JIB. In conclusion, patients with JIB may require higher doses of ME-CsA.
Ther Drug Monit 2003 Dec
PMID:Dose-adjusted cyclosporine c2 in a patient with jejunoileal bypass as compared to seven other liver transplant recipients. 1463 52

The prevalence of primary adult lactose malabsorption (LM) in 23 ethnic groups was matched with national data on milk consumption and mortality rates from ischaemic heart disease (HD). In 6 other ethnic groups prevalence of LM was related to unquantified assessments of milk consumption and frequency of IHD. On the available data, populations with a prevalence of LM over 30%, and whose consumption of milk is low or is largely in low lactose form, have a lower risk of IHD mortality than populations with a prevalence of LM under 30% and a high milk consumption. There is evidence against attributing these findings to genetic linkage between susceptibility to IHD mortality and persistent lactose absorption, or to differences in socio-economic development, cigarette consumption or intake of animal fats. The findings are compatible with an hypothesis that, if the correlation reported previously between milk consumption and IHD mortality is causal, lactose could be the responsible dietary factor.
 ...
PMID:Hypothesis: is lactose a dietary risk factor for ischaemic heart disease? 1872 62

Currently, therapeutic drug monitoring (TDM) of antiretroviral therapy (ART) is not performed in the United States as part of routine clinical care of an HIV-infected adolescent patient. TDM is recommended to rule out subtherapeutic drug concentrations and to differentiate among malabsorption, drug interactions, poor adherence, or increased drug metabolism or clearance as possible causes of decreased drug exposure. The use of TDM is also considered to assist in finding the optimal dose of a drug in patients whose virus has shown reduced susceptibility to that drug. The dosing of antiretroviral (ARV) drugs in adolescent patients with HIV infection depends on the chronologic age, weight, height, and the stage of sexual maturation. As a result of the limited data on the pharmacokinetics of ART during puberty, the transition of a dosing regimen from higher pediatric (weight and surface-based) to adult (fixed) range is not well defined. Developmental pharmacokinetic differences contribute to high variability in pediatric and adolescent patients and an increased frequency of suboptimal ARV exposure as compared to in adults. Individualized, concentration-targeted optimal dosing of ARV medications can be beneficial to patients for whom only limited dosing guidelines are available. This article describes three cases of the application of TDM in treatment-experienced adolescent patients whose ART was optimized using ARV TDM. TDM of ARV drugs is useful in managing the pharmacotherapy of HIV in adolescent patients and is well received by the adolescent patients with HIV and their families. Among others, the benefits of TDM provide evidence for adherence interventions and create grounds for enhanced education of the adolescent patient and involved adult caregivers about ART. Finally, TDM in adolescents provides valuable information about the clinical pharmacology of ART during puberty.
Ther Drug Monit 2010 Jun
PMID:Can therapeutic drug monitoring improve pharmacotherapy of HIV infection in adolescents? 2044 85