Long-term stability of cimetidine in total parenteral nutrition

A.S.P.E.N. clinical guidelines: parenteral nutrition ordering, order review, compounding, labeling, and dispensing

BACKGROUND

Parenteral nutrition (PN) is a high-alert medication available for patient care within a complex clinical process. Beyond application of best practice recommendations to guide safe use and optimize clinical outcome, several issues are better addressed through evidence-based policies, procedures, and practices. This document provides evidence-based guidance for clinical practices involving PN prescribing, order review, and preparation.

METHOD

A systematic review of the best available evidence was used by an expert work group to answer a series of questions about PN prescribing, order review, compounding, labeling, and dispensing. Concepts from the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) format were applied as appropriate. The specific clinical guideline recommendations were developed using consensus prior to review and approval by the American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) Board of Directors. The following questions were addressed: (1) Does education of prescribers improve PN ordering? (2) What is the maximum safe osmolarity of PN admixtures intended for peripheral vein administration? (3) What are the appropriate calcium intake and calcium-phosphate ratios in PN for optimal neonatal bone mineralization? (4) What are the clinical advantages or disadvantages of commercially available premade ("premixed") multichambered PN formulations compared with traditional/customized PN formulations? (5) What are the clinical (infection, catheter occlusion) advantages or disadvantages of 2-in-1 compared with 3-in-1 PN admixtures? (6) What macronutrient dosing limits are expected to provide for the most stable 3-in-1 admixtures? (7) What are the most appropriate recommendations for optimizing calcium (gluconate) and (Na- or K-) phosphate compatibility in PN admixtures? (8) What micronutrient contamination is present in parenteral stock solutions currently used to compound PN admixtures? (9) Is it safe to use the PN admixture as a vehicle for non-nutrient medication delivery? (10) Should heparin be included in the PN admixture to reduce the risk of central vein thrombosis? (11) What methods of repackaging intravenous fat emulsion (IVFE) into smaller patient-specific volumes are safe? (12) What beyond-use date should be used for (a) IVFE dispensed for separate infusion in the original container and (b) repackaged IVFE?

Continuous infusion of methylprednisolone via paediatric parenteral nutrition: A pharmacokinetic animal study

BACKGROUND & AIMS

The aim of our study consisted to measure the pharmacokinetic parameters of methylprednisolone administered in a continuous infusion of a paediatric parenteral nutrition mixture for 24h in the rabbit.

METHODS

Fourteen rabbits were split into two groups and assigned a different administration vehicle (all-in-one or two-in-one nutrition mixture). We used USC PACK* pharmacokinetics software to compare the influence of the composition of the paediatric parenteral nutritional solutions on the values of the pharmacokinetic parameters of methylprednisolone.

RESULTS

Neither the steady-state plasma concentrations of methylprednisolone hemisuccinate nor the values of the pharmacokinetic parameters of methylprednisolone differed significantly when administered in two-in-one or all-in-one nutrition mixtures.

CONCLUSIONS

The composition of the nutritional medium had no discernable effect on the bioavailability of methylprednisolone. Neither the speed at which the steady-state plasma concentration was reached, nor the values of the pharmacokinetic parameters of methylprednisolone were significantly modified.

Stability and compatibility of histamine H2-receptor antagonists in parenteral nutrition mixtures

PURPOSE OF REVIEW

To examine the stability and compatibility of histamine H2-receptor antagonists in parenteral nutrition admixtures in order to provide well tolerated and effective therapy.

RECENT FINDINGS

Many stability investigations were carried out before 2005, but no critical appraisal of published data has been undertaken. H2-receptor antagonists are stable in most parenteral nutrition admixtures for 2-48 h, with long-term stability up to 4 weeks claimed for a few combinations. Some earlier data are questionable in the light of more recent analytical technology and pharmaceutical knowledge regarding stability assessment. As stability is dependent upon the source of constituents, we have listed all products tested and their respective manufacturers. A general recommendation is made not to store H2-receptor antagonists in parenteral nutrition for more than 24 h at refrigerated temperature before use.

SUMMARY

Administration of H2-receptor antagonists in parenteral nutrition admixtures has several clinical and economical advantages, but, in order for these benefits to be well tolerated and efficacious, the stability and compatibility of the drugs, as well as the parenteral nutrition components after mixing, have to be ascertained. Factors that influence stability are assessed, the need for more controlled study protocols is evaluated and recommendations are made for safe storage and administration.