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Even though there is an abundance of research related to the clinical and physiologic effects of parenteral nutrition and specific nutritional substrates, few new products have been released for clinical use. This review illustrates some of the directions being taken in the future development of parenteral nutrition products and some new perspectives related to the current effects (or lack of effects) of TPN. When considering the individual effects of specific nutrient substrates (arginine, glutamine, LCTs, MCTs, SCFAs) as reviewed here, it becomes apparent that the infusion of parenteral nutrition has the potential to produce a variety of metabolic responses that could be both beneficial and harmful. These effects depend on the type and quantity of substance infused as well as the disease and clinical condition of the patient. This also is true for those substances (GH, IGF-1) being evaluated to direct the effects of TPN infusions in a manner that improves protein accretion and supports the immunologic response of the body. At best, these investigations are producing a great amount of new and more specific information about the metabolic response to illness and the effects of TPN and individual substrate on that response.

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The advent of ready-to-use intravenous (IV) delivery systems, particularly small-volume parenterals less than 250 mL has contributed greatly to pharmacy and patient care. Since their introduction in the late 1970s, the availability and variety of systems have increased. The purpose of this article is to update practitioners on small-volume parenterals systems that have a large product availability requiring little manipulation to make the system patient-specific. Additional benefits such as extended stability, potential for decreasing waste of products, as well improved end-quality are also discussed. With the benefits described that these systems have over the traditional method of preparing small-volume parenterals, there is still hesitation to fully utilize these systems. The primary reason for this seems to be the issue of cost. With various rebate incentive programs offered by manufacturers as well as the benefits that the systems provide, ready-to-use IV delivery systems are comparable in price to the traditional method of preparing small-volume parenteral agents.

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Drug absorption from the gastrointestinal (GI) tract and the impact of GI surgery and disease on drug absorption are discussed. Recommendations are made to manage problems of drug malabsorption. Absorption from the GI tract is a first-order process described by its rate and extent. GI surgery changes the anatomy of the GI tract and alters important variables in the absorption process. In the wake of procedures which diminish small bowel surface area, the extent of absorption of phenytoin, digoxin, cyclosporin, aciclovir, hydrochlorothiazide and certain oral contraceptives is reported to be reduced. The underlying cause of the reduction is unknown. When gastric emptying time or pH are altered by surgery, the rate of drug absorption appears to be reduced. However, it is not clear which variable is more important in determining therapeutic effects. The effects of coeliac and inflammatory bowel diseases on the distribution and clearance of drugs must be considered before attributing abnormal serum concentrations of drugs to malabsorption. GI disease may slow gastric emptying and delay the complete absorption of drugs when their rate of absorption depends on gastric emptying time. Other inflammatory GI diseases such as graft-versus-host disease (GVHD) of the gut, Behçet's syndrome and scleroderma involving the GI tract may directly reduce absorption of drugs such as cyclosporin, amitriptyline, benzodiazepines, anticonvulsants, paracetamol (acetaminophen) and penicillamine. GI diseases which alter gut pH affect the absorption only of drugs with limited water solubility and pH-dependent dissolution such as ketoconazole. Clinicians should be aware of the variable absorption seen after GI disease and surgery and monitor their patients accordingly.

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It is well recognized that drug absorption from the gastrointestinal tract is influenced by gastric and intestinal motility, surface area available for absorption, and physicochemical properties of the drug. Disease and surgery have been shown to alter these factors. Consequently, drug absorption can be altered as well, and these affect drug therapy. Apparently this effect is variable, but the variability may be due in part to the complexities of performing studies in this area. For example, many patient factors as well as drug characteristics must be considered. In addition, appropriate interpretation of results requires that intravenous data be collected if changes in absorption are based on bioavailability. At this time, the alterations in drug absorption due to gastrointestinal disease and surgery are of unknown or little clinical significance; nevertheless, clinicians should be aware that the possibility of malabsorption exists and anticipate any monitoring of or alterations in therapy that may have to be made.

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We used a novel approach to cost-justify clinical pharmacy services on a general surgery team in nine diagnosis-related group cases. The clinical pharmacist monitored nine patients longitudinally on a general surgery team from admission to discharge and intervened in their therapeutic management. Each recommendation was analyzed for rationale, acceptance, perceived impact on quality and/or cost of patient care, whether self-initiated or solicited, and impact on patient outcome. Types of recommendations and outcomes were categorized by process and outcome measurement criteria. Total cost avoidance per patient was calculated using costs of drug therapy, laboratory tests, and length of stay. Accounting for cost of clinical pharmacy services, net cost avoidance per patient was calculated. The clinical pharmacist made 101 recommendations on nine patients. Physicians accepted 82 percent of the recommendations; 77 percent of the recommendations were self-initiated and 23 percent were solicited. Recommendations had a perceived impact on cost, quality, or both at 13, 31, and 56 percent, respectively. Most recommendations (79 percent) brought patient therapy to a level of conformance with current standards of practice as documented in the medical literature. Recommendations that potentially preserved a major organ function by preventing drug-induced toxicity or the exacerbation of existing problems constituted 16 percent of the total. None of the accepted recommendations adversely affected patient outcome and 23 percent directly resulted in a measurable positive outcome in patient care. A total of four hospital days was potentially saved for two cases. Based on objective outcome criteria, a 1.9-day increase in therapeutic control was documented per patient.(ABSTRACT TRUNCATED AT 250 WORDS)

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The stability of amino acids in total parenteral nutrient (TPN) solutions stored for 30 days and the potential for stored TPN solutions to support growth of microbial contaminants were studied. Solutions of 3.5% crystalline amino acids and 25% dextrose with electrolytes were prepared either by using a commercially available amino acid solution with electrolytes or by adding electrolytes individually to a base TPN solution. Solutions were stored in polyvinyl chloride bags at refrigerated (4 degrees C) or room (25 degrees C) temperature for 30 days. Some bags were inoculated with Candida albicans or Pseudomonas maltophilia before storage to serve as positive controls for evaluation of microbial contamination. At appropriate intervals, bags of each type of solution under each storage condition were analyzed for amino acid content. Microbial growth was evaluated by filtering the contents of each bag and incubating the filter in brain-heart infusion broth. No microbial growth was detected in any of the study solutions, but all solutions inoculated with C. albicans and 2 of 16 solutions inoculated with Ps. maltophilia had evidence of growth. No significant decreases in the concentrations of any of the amino acids were noted for solutions stored at refrigerated temperature, but significant decreases in the concentrations of arginine and methionine were noted for solutions stored at room temperature. Total parenteral nutrient solutions can be stored for up to 30 days if they are kept at refrigerated temperatures and protected from light; however, quality assurance measures for these solutions should include end-product microbiologic testing.

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The effects of chronic phenytoin therapy on serum calcium, phosphorus, folate, and various hematological indices were assessed. One hundred and fifty-one patients, ages 18 months to 81 years, received phenytoin in a previously-conducted, double-blind, placebo-controlled study. Of the patients receiving phenytoin, initially 127 were evaluable while for control patients receiving placebo, 116 were evaluable. All patients had various laboratory parameters monitored at one day post-loading dose, one week, 1,3,6,9,12,15,18,21, and 24 months. Laboratory values examined were serum calcium, phosphorus, folate, white blood cell count with differential, hemoglobin, hematocrit, and red blood cell and platelet counts. A statistical analysis using the t-test method was employed to evaluate data. Data are reported as mean values +/- standard deviation. Patients suffering early hypersensitivity, manifested by a morbilliform skin rash, were removed from the drug by day 30 and were not included in the chronic therapy review. Results indicate that the various laboratory values examined were not significantly affected by phenytoin administration in the patient population. Therefore, chronic phenytoin therapy following the initial hypersensitivity period does not cause abnormal laboratory values as followed in this study.

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