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Approach to Parenteral Nutrition
Topic 9
Module 9.3
Compounding, Drugs and Nutritional Admixtures in PN
Stefan Mühlebach
University Hospital Berne
Berne, Switzerland
Learning Objectives
• To know the different systems for parenteral nutrition; their advantages and limits;
• To know the risks associated with the compounding/ready-to-use preparation of AiO PN
admixtures (GMP and potential incompatibility reactions) and the pharmacist’s tasks and
responsibility for an admixing service;
• To understand the general advice not to admix drugs to PN AiO admixtures, unless documented
or of a vital need;
• To understand to apply a risk assessment for adding an i.v. drug to an AiO admixture for both
the influence of a drug on a PN admixture and the influence of a PN admixture on the fate of a
drug.
Contents
1. Introduction
1.1. PN: from separate nutrient infusion to the all-in-one admixture
1.2. AiO admixtures: prerequisites, benefits, and limits
1.3. Industrial PN admixtures: the multi-chamber bag
2. PN compounding and admixing
2.1. Good Manufacturing Practice (GMP)
2.2. Aseptic preparation technique
2.3. Compatibility and stability aspects of AiO admixtures
2.4. Drug admixing to an AiO PN formulation
3. Summary
Key Messages
• The all-in-one concept is a milestone in the search for safe, efficient, and convenient PN in
acute and (home) long-term treatment. It has stimulated technical and pharmaceutical
developments;
• Standard AIO regimes are used in most cases for PN treatment of adult patients in hospital
acute care. Nevertheless, individualised and tailor-made PN admixtures are also needed to meet
the specific nutritional requirements of children (growth), those with severe illnesses including
organ failures, and patients on a long-term (home) PN. Well designed cost-effectiveness studies
are still lacking;
• The compounding of AiO admixtures or the final ready-to-use preparation of industrial AIO
premixes are critical pharmaceutical issues. Good manufacture practice (GMP) rules have to be
respected when compounding AiO PN or admixing nutritional components and drugs. The
pharmacist as the manufacturing supervisor has to take specific responsibility to guarantee
quality and stability of ready-to-use prepared admixtures. As a nutrition support team member
he has to define and implement standards of correct storage and handling of AiO admixtures.
These standards must reflect professional state of the art practice;
• Because of their complex composition and the character of o/w emulsions, PN AiO admixtures
have high and potentially harmful instability risks. Instability reactions include physico-chemical
Copyright © 2007 by ESPEN
incompatibilities and microbial instability due to incorrect aseptic manipulation technique both
of which represent avoidable medication errors. The most important incompatibility and
instability reactions in AiO admixture can be classified according to their physico-chemical
reaction type: emulsion deterioration, lipid peroxidation, oxidation of vitamins, and formation
of insoluble precipitates. Measures to avoid them therefore need pharmaceutical expertise and
advice and depend on the characteristics of the pharmaceutical nutrient or drug concerned;
• AiO admixtures are not suitable as drug vehicles due to their complex formulation and the high
potential for interaction in vivo and in vitro. If admixture of a drug is necessary, it is helpful to
have a simple and easy to understand procedure for risk assessment, based on the degree of
need for the medication and on the physico-chemical profiles of the AiO admixture and the
drug.
Copyright © 2007 by ESPEN
1. Introduction
1.1 PN: From Separate Nutrient Infusion to the All-In-One Admixture
From its early beginnings, parenteral nutrition (PN) encountered multiple (pharmaceutical)
challenges (1), (Table 1). Over the last 40 years PN has evolved technically from a difficult to
handle multi-bottle (MB) system to a partial PN admixture, and eventually to an all-in-one
admixture system. Ideally, an AiO PN admixture is administered in a single container containing the
whole daily nutritional requirements through a single central i.v. line (2), (Fig. 1).
Table 1 Challenges in PN
Type Issue
Parenteral formulation of nutrients Pharmaceutical
Need for hypertonic solutions for volume limitation Pharmaceutical
Long-term (central) venous access (catheters) Technical
Practicability, efficacy, and safety of (long-term) PN Medical, nursing care-
related, pharmaceutical
Strict asepsis during compounding and administration Pharmaceutical
Prevent/correct metabolic, physico-chemical disturbances Medical, pharmaceutical
Figure 1 PN from multiple bottles to AIO admixtures
The large number of dissolved components in AiO PN mixtures forms a complex pharmaceutical
formula which, even in vitro, has an important number of potential physico-chemical interactions
(incompatibilities), which may adversely affect the stability of the mixture and its individual
components. These pharmaceutical aspects have a major impact on the quality, safety, and
effectiveness of PN (3, 4, 5).
The incompatibility issue becomes even more complicated if drugs have to be added to an AiO
formula (6), (Fig. 2). Correct pharmaceutical advice is necessary to avoid incompatibilities to be
seen as preventable medical errors.
Copyright © 2007 by ESPEN
Figure 2 Drug admixing to PN: Aspects of concern
Ready-to-use AIO admixtures fulfil stability requirements only under restricted and specific
conditions of storage and administration; the main restriction is imposed by their limited shelf life
of only a few days once all the ingredients have been added. This does not allow the large scale
industrial preparation of fully ready to use AIO admixtures. The final ready to use product depends
therefore upon the availability of a specialist compounding service, in hospital or centrally, with the
capability of delivering the freshly compounded product to its site of use.
1.2 AiO Admixtures: Prerequisites, Benefits, and Limits
The specific needs of different nutrients in each patient lead to a small therapeutic index of a clinical
nutrition formula in a given individual (Table 2).
Table 2 PN Nutrient requirements
Neonate Adult AIO Admixture “1850-16”
Mean for a 75 kg patient
[absolute dose]
Energy requirements [kcal/kg]
Non protein energy 90-110 30 1875
Basic metabolic rate 35-50 15-20
Growth 45 -
Macronutrients [g/kg]
Glucose 16-20 5 350 (1400 kcal)
Triglycerides 2-3 1 50 (450 kcal)
Essential FA (C18:2) 0.1-0.25 0.02-0.04 27
Protein (aa pattern!) 2.0-3,5 0.8-1.8 100g (16 g N)
Electrolytes [mmoles/kg]
Na 2.5 1 100
K 1-3 1 60
Ca 1-2 0.05 4
Mg 0.5 0.15 5
Phosphate 2 0.2 24
Water [ml/kg] 60-130 30 1950
Micronutrients (RDA)
Vitamins
Vit. A (retinol) 1000 μg 1000 *
Vit D (cholecalciferol) 5-10 μg 5.5 *
Copyright © 2007 by ESPEN
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