Esomeprazole administered through a nasogastric tube provides bioavailability similar to oral dosing

Intestinal Drug Absorption After Subarachnoid Hemorrhage and Elective Neurosurgery: Insights From Esomeprazole Pharmacokinetics

OBJECTIVES

Subarachnoid hemorrhage (SAH) may critically impair cardiovascular, metabolic, and gastrointestinal function. Previous research has demonstrated compromised drug absorption in this group of patients. This study aimed to examine the impact of SAH on gastrointestinal function and its subsequent effect on the absorption of enterally administered drugs, using esomeprazole as a probe drug.

DESIGN

Prospective observational cohort study.

SETTING

Academic hospital in Germany.

PATIENTS

We included 17 patients with high-grade SAH and 17 controls, comparable in age, sex, body weight, and renal function, who underwent elective cranial surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Both groups received esomeprazole per standard protocol to prevent acid-associated mucosal damage, either orally or through a nasogastric tube. On day 4, esomeprazole was administered IV to estimate oral bioavailability. Esomeprazole serum concentrations were measured on days 1, 3, and 4 in both groups and on day 7 in the SAH group. Patients with high-grade SAH exhibited severely impaired drug absorption. Most patients showed no improvement in intestinal drug absorption even a week after hemorrhage.

CONCLUSIONS

Following SAH, significantly reduced drug absorption may be attributed to decreased intestinal motility and compromised intestinal mucosal function. Clinicians should anticipate the reduced effectiveness of enterally administered medications for at least seven days after high-grade SAH.

Drug administration via feeding tubes-a procedure that carries risks: systematic identification of critical factors based on commonly administered drugs in a cohort of stroke patients

PURPOSE

Drug administration via feeding tubes is considered a process with many uncertainties. This review aimed to give a comprehensive overview of data available on feeding tube application and to carry out risk assessments for drug substances commonly administered to stroke patients.

METHODS

Drugs frequently administered via feeding tubes were identified through a retrospective analysis of discharge letters from a stroke unit. Physicochemical, pharmacokinetic, and stability properties of these drugs and data on drug-enteral nutrition interactions were systematically searched for in the European Pharmacopoeia, Hagers Handbook of Pharmaceutical Practice, Birchers clinical-pharmacological data compilation, and the Martindale Complete Drug Reference, as well as from databases including DrugBank, DrugDex, PubChem, Google Scholar, and PubMed.

RESULTS

Of the drugs most commonly administered via feeding tubes in the present stroke patient cohort, bisoprolol, candesartan, and ramipril could be considered the least critical due to their overall favourable properties. Acetylsalicylic acid, amlodipine, hydrochlorothiazide, omeprazole and esomeprazole, simvastatin, and torasemide pose risks based on pH or light-dependent instability or proposed food effects. The most critical drugs to be administered via feeding tubes are considered to be furosemide, levodopa, and levothyroxine as they show relevant instabilities under administration conditions and substantial food effects; the latter two even possess a narrow therapeutic index. However, little information is available on drug-tube and drug-formula interactions.

CONCLUSION

Feeding tube administration of medications turned out to be a highly complex process with several unmet risks. Therefore, investigations that systematically assess these risk factors using clinically relevant model systems are urgently needed.

Enteral Delivery of Pravastatin Sodium Tablets: Effect of Compounding into a Liquid Form and Co-Administration of Enteral Nutrition

BACKGROUND

Compounding solid oral dosage forms into liquid preparations is a common practice for administering drug therapy to patients with swallowing difficulties. This is particularly relevant for those on enteral nutrition, where factors such as the administration procedure and co-administration of enteral nutrition play crucial roles in effective drug delivery. Due to the limited studies focused on this practice, the impact of co-administered nutrition remains unclear.

METHODS

Pravastatin tablets were compounded into two liquid formulations and administered through three independent tubes for ten cycles. The drug amount was quantified upstream and downstream of the tubes both with and without different (fiber content) nutritional boluses.

RESULTS

The compounding procedure did not lower the drug amount with respect to the original tablets. However, when the liquid formulation was pumped through the tubes, a statistically significant reduction in the pravastatin administered (between 4.6% and 11.3%) was observed. The co-administration of different nutritional boluses or the compounding procedure did not affect the general results.

CONCLUSIONS

Pravastatin loss appears unavoidable when administered via the enteral tube. Although, in this case, the loss was of limited clinical relevance, it is important not to underestimate this phenomenon, especially with drugs having a narrow therapeutic index.

Oral Drug Absorption and Drug Disposition in Critically Ill Cardiac Patients

(1) Background: In critically ill cardiac patients, parenteral and enteral food and drug administration routes may be used. However, it is not well known how drug absorption and metabolism are altered in this group of adult patients. Here, we analyze drug absorption and metabolism in patients after cardiogenic shock using the pharmacokinetics of therapeutically indicated esomeprazole. (2) Methods: The pharmacokinetics of esomeprazole were analyzed in a consecutive series of patients with cardiogenic shock and controls before and after elective cardiac surgery. Esomeprazole was administered orally or with a nasogastric tube and once as an intravenous infusion. (3) Results: The maximum plasma concentration and AUC of esomeprazole were, on average, only half in critically ill patients compared with controls (p < 0.005) and remained lower even seven days later. Interestingly, esomeprazole absorption was also markedly compromised on day 1 after elective surgery. The metabolites of esomeprazole showed a high variability between patients. The esomeprazole sulfone/esomeprazole ratio reflecting CYP3A4 activity was significantly lower in critically ill patients even up to day 7, and this ratio was negatively correlated with CRP values (p = 0.002). The 5'-OH-esomeprazole and 5-O-desmethyl-esomeprazol ratios reflecting CYP2C19 activity did not differ significantly between critically ill and control patients. (4) Conclusions: Gastrointestinal drug absorption can be significantly reduced in critically ill cardiac patients compared with elective patients with stable cardiovascular disease. The decrease in bioavailability indicates that, under these conditions, any vital medication should be administered intravenously to maintain high levels of medications. After shock, hepatic metabolism via the CYP3A4 enzyme may be reduced.

Model-Based Prediction of Acid Suppression and Proposal of a New Dosing Regimen of Fexuprazan in Humans

Fexuprazan is a potassium-competitive acid blocker (P-CAB). The compounds in this newly developed drug family suppress intragastric acidity. As there are already other acid-suppressing drugs on the market, such as H₂ antagonists and proton pump inhibitors (PPIs), it would be informative to compare the biological effects of fexuprazan against another approved drug with the same indication. The drug concentration predicted by the pharmacokinetic (PK) model could serve as an input function for a pharmacodynamic (PD) model. The apparent pharmacokinetics of fexuprazan could be described by a simpler model. However, a physiologically based pharmacokinetic (PBPK) model was developed in a previous study. A one-compartment model was also proposed in the present study. Both the newly suggested model and the previously validated PBPK model were used as input functions of the PD models. Our simulation revealed that the effects of fexuprazan could be effectively simulated by the proposed PK–PD models. A PK–PD model was also proposed for the oral administration of the PPI reference drug esomeprazole. A model-based analysis was then performed for intragastric pH using several dosing methods. The expected pH could be predicted for both drugs under several dosing regimens using the proposed PK–PD models.

A systematic approach for assessing the suitability of enteral feeding tubes for the administration of controlled-release pellet formulations

Enteral nutrition plays an important role for patients who are unable to properly swallow food. In such patients, enteral feeding tubes are often used, through which food, but often also oral medications, are administered. However, this can pose the risk of tube clogging. Compared to the administration of crushed tablets, multiparticulate dosage forms are often considered easier to administer and furthermore have the advantage of enabling the administration of even controlled-release preparations. The objective of this systematic study was to identify tube- and formulation-related factors that contribute to successful administration of coated pellet formulations via a variety of commercially available feeding tube devices. The suitability of enteral feeding tubes for the administration of controlled-release pellet formulations that differed in size and type of starter core and functional coating was investigated in a stepwise approach using a novel in vitro setup. Results of the study indicate that pellet diameter and inner diameter of the feeding tube are by no means reliable parameters for estimating the tube's suitability for pellet administration, but that many other tube and formulation-related factors and combinations thereof must be considered to ensure safe and effective drug administration via enteral feeding tubes.

In vitro Approaches to Support Bioequivalence and Substitutability of Generic Proton Pump Inhibitors via Nasogastric Tube Administration

Administration of proton pump inhibitors (PPIs) through nasogastric tubes may present risks. If the PPI drug products are not prepared properly, clogging or obstruction of nasogastric tubes can pose a safety concern. In addition, the integrity of the enteric coating of the drug product may be damaged resulting in reduced bioavailability of the active moiety. From the perspective of administration of generic PPIs when compared to the reference drug product, differences in formulation can potentially result in a greater relative risk for the generic drug product. As part of the assessment of bioequivalence, the Office of Generic Drugs (OGD) has developed a suite of in vitro testing to compare the delivery of the generic and reference products via nasogastric tubes. These in vitro tests assess essential attributes associated with the likelihood of clogging and maintenance of the enteric coating. These in vitro tests include studies evaluating sedimentation, granule size distribution, drug recovery, and acid resistance. One of the challenges is that while the administration of PPIs through nasogastric tubes is common in clinical practice, this issue is not uniformly addressed in the FDA approved label of the reference drug products. This paper discusses the design and rationale for in vitro testing of PPI formulations with respect to bioequivalence via nasogastric tube administration and in addition, it summarizes commonly occurring deficiencies in the in vitro nasogastric tube testing of 14 recent Abbreviated New Drug Applications (ANDA) submitted for five generic PPI drug products.

In Vitro Evaluation of Nasogastric Tube Delivery Performance of Esomeprazole Magnesium Delayed-Release Capsules

Enteral feeding tubes are used to deliver food or drugs to patients who cannot swallow. To deliver delayed-release drugs that are formulated as enteric coated granules to these patients via feeding tubes requires that they be suspended in water before administration. Importantly, the suspension of enteric granules in water of varying pH can cause damage to the enteric coating and affect the bioavailability of the drug. Here, analytical methods for testing acid resistance stability and particle size distribution (PSD) of esomeprazole granules were used to monitor the integrity of the granule enteric coating after water pretreatment and delivery through an oral syringe and nasogastric (NG) tube. Granules from esomeprazole magnesium delayed-release capsules were transferred to an oral syringe, suspended in water, and delivered on the bench through an NG tube. Subsequently, acid resistance stability (i.e., the amount of drug released after 2-h acid dissolution) was determined via high-performance liquid chromatography, and the PSD were measured with a laser diffraction system. All the granules demonstrated acid resistance stability when the granules were delivered immediately (0 min incubation) through the oral syringe and NG tube. In contrast, some granules demonstrated significant drug release during acid exposure after a 15-min incubation period which mimics a possible delay in delivery of the drug from the syringe by the caregiver. A bimodal PSD was observed with these granules, which was attributed to debris from damaged enteric coating and particle agglomeration. The methods developed in this study could be used to distinguish batches with suboptimal product quality for delivery using NG tubes and to confirm the substitutability of generic drug products for this alternative route of administration.

Therapeutic concerns when oral medications are administered nasogastrically

WHAT IS KNOWN AND OBJECTIVE

Administering oral medications to patients with nasogastric tube (NGT) is a challenging patient-care issue. Inappropriate prescribing behaviour and incorrect procedure for extemporaneous preparation of oral suspensions given via NGT may result in significant harm to patients. There are many drugs which have not been tested regarding oral absorption profile and bioavailability derived from NGT dosing. Although several studies and case-reports have been reported, there is no up-to-date review of drug administration via NGT. The aim of this review is to increase awareness of rational drug administration via NGT and to encourage relevant research in this area.

METHODS

Full prescribing information from each currently available oral medication was reviewed for any data indicating that the medication could not be crushed or opened. Literature was identified by searching PubMed (1988 to Aug 2012).

RESULTS AND DISCUSSION

There is evidence to show that NGT dosing of some medications may bring both benefits (e.g. cost saving) and disadvantages (e.g. decrease in efficacy and/or safety). For medications with package inserts that warn that they should not be crushed or opened, alternatives are usually recommended. However, in some cases, there is evidence to support NGT dosing. Sometimes special procedures are required to avoid problems such as instability, interaction with enteral nutrition, adsorption, tube obstruction and low recovery when preparing extemporaneous oral suspensions.

WHAT IS NEW AND CONCLUSION

Physicians, pharmacists and nurses should know the procedures for drug administration by NGT, as well as the latest evidence on such administrations. There may not be bioequivalence between oral and nasogastric administrations. Care must be taken to avoid compromising the physicochemical, biopharmaceutical and pharmacological properties of drugs given by NGT to ensure their safety and efficacy.

Appropriateness of administration of nasogastric medication and preliminary intervention

A utilization study was performed in a 2200-bed tertiary care teaching hospital. Data mining was performed on all nasogastric medication prescriptions for patients hospitalized in 2011. Nurses were interviewed by questionnaire. A PDCA (Plan-Do-Check-Act) cycle was used for continuous quality improvement. The proportion of patients with nasogastric tubes (NGT) was 3.2%. A large number of medical orders (n = 6261) involved nasogastric medications with a package insert particularly noting that they should not be crushed or opened (group 1) or medications without a specific formulation recommendation in the package insert but having evidence discouraging NGT dosing (group 2). Of the nasogastrically administered sustained-release or controlled-release formulations, a sustained-release sodium valproate tablet formulation was the most prescribed drug and a sustained-release 2.5 mg felodipine tablet was prescribed with the highest proportion of NGT dosing [NGT/(NGT + oral) = 12.3%]. Among the nasogastrically administered enteric-coated formulations, a myrtol-standardized enteric-coated capsule formulation was the most prescribed drug and a pantoprazole tablet formulation was prescribed with the highest proportion of NGT dosing [NGT/(NGT + oral) = 19.3%]. Proportions of NGT dosing for amiodarone and carbamazepine (group 2) were 4.8% and 6.3%, respectively. The percentage of nurses with adequate knowledge about pharmaceutical dosage formulations was 60%. The rate of answering correctly as to whether medications in group 1 could be crushed or opened was only 30%. Awareness of evidence discouraging NGT dosing of medications in group 2 was zero. Most nurses (90%) left physicians and pharmacists with the entire responsibility for knowledge and decision-making concerning route of drug administration. After a 3-month preliminary intervention, irrational medical orders involving nasogastric administration of medications in group 1 were successfully abolished. The rate of answering correctly as to whether medications in group 1 could be crushed or opened increased to 100%. This utilization study indicates poor awareness concerning nasogastric administration of medication on the part of physicians and nurses, and preliminary intervention measures were efficient in improving knowledge through team cooperation and effort.

A new esomeprazole packet (sachet) formulation for suspension: in vitro characteristics and comparative pharmacokinetics versus intact capsules/tablets in healthy volunteers

BACKGROUND

A packet (sachet) formulation of esomeprazole for suspension has been developed for use in patients who have difficulty swallowing.

OBJECTIVES

This article reports the in vitro characteristics of the new esomeprazole formulation, including stability in suspension and suitability for administration orally or via enteral tubes. It also describes the pharmacokinetic profile of the esomeprazole 40-mg packet compared with that of existing solid dosage forms (capsules and tablets) in a clinical bioequivalence study.

METHODS

The stability in suspension of the packet formulation was assessed after reconstitution at various strengths (2.5, 10, and 40 mg) and a different pH (3.4-5.0) in strength-appropriate volumes of water held at temperatures ranging from 5 degrees C to 37 degrees C for up to 60 minutes. Suitability for oral administration was examined in terms of reconstitution time and the actual dose delivered after simulated oral administration, as well as in terms of the actual dose delivered by enteral tubes ranging in diameter from 6 to 20 Fr. Chemical stability and suspension characteristics were also analyzed using alternative reconstitution vehicles (applesauce, apple juice, and orange juice). The comparative pharmacokinetics of the packet, capsule, and tablet formulations of esomeprazole were evaluated in a randomized, open-label, 3-way crossover study in healthy volunteers, who received single 40-mg doses of each formulation. Bioequivalence was assumed if the 90% CIs for the ratios of the geometric mean AUC and CmaX were between 0.80 and 1.25. Reversephase liquid chromatography with ultraviolet detection was used to assess the esomeprazole content and/or degradation products of esomeprazole in the tests for in-suspension stability, dose delivery, and acid resistance. Normal-phase liquid chromatography was used to assess the esomeprazole content of the plasma samples in the bioequivalence study.

RESULTS

At the pH and temperature ranges investigated, the packet formulation was stable for up to 60 minutes after reconstitution. Chemical degradation was low (<0.1%) for all reconstitution vehicles investigated. Reconstitution time was 2 minutes with water and 9 to 10 minutes with apple or orange juice. Dose delivery was >/=98% after simulated oral administration and was generally >/=96% after administration via enteral tubes. Ninety-six healthy volunteers (56 women, 40 men; mean age, 24.9 years; mean weight, 68.9 kg) participated in the randomized, crossover, comparative pharmacokinetic study of the packet and capsule/tablet formulations. The estimated ratios of the geometric mean AUC and C(max) for the packet:capsule and packet: tablet formulations were 0.98 (90% CI, 0.93-1.03) and 0.99 (90% CI, 0.94-1.04), respectively.

CONCLUSIONS

In these analyses, the packet (sachet) formulation of esomeprazole was chemically stable in suspension and when administered orally and via enteral tubes. The formulation had a short reconstitution time, remaining fully dispersed in water for at least 30 minutes, and was dispersed in applesauce, apple juice, or orange juice without compromising its stability or dispersion characteristics. The packet formulation met the regulatory definition for bioequivalence to the tablet and capsule formulations.

Effect of timing of dosing in relation to food intake on the pharmacokinetics of esomeprazole

AIM

To investigate the pharmacokinetics of esomeprazole before a high-fat meal vs. fasting.

METHODS

This open-label, randomized, crossover study consisted of two 5-day dosing periods of esomeprazole 40 mg per day. On days 1 and 5, subjects received esomeprazole 15 min before a high-fat meal (fed) or 4 h before a non-high-fat meal (fasting).

RESULTS

On days 1 and 5, ratio of fed to fasting area under the plasma concentration-time curve [0.56, 90% confidence interval (CI) 0.50, 0.64, and 0.78, 90% CI 0.74, 0.82, respectively] and peak plasma concentration (0.34, 90% CI 0.28, 0.41, and 0.47, 90% CI 0.41, 0.52, respectively) were outside of the limits of bioequivalence.

CONCLUSIONS

Esomeprazole bioavailability was reduced when taken within 15 min before eating a high-fat meal vs. that while fasting.

An in vitro comparison of different providers to deliver four proton pump inhibitor products through a feeding tube

BACKGROUND

It is unclear how delivery through a feeding tube compares between esomeprazole in water, lansoprazole oral disintegrating tablet in water, omeprazole/NaHCO(3) in water and simplified lansoprazole suspension.

AIM

This in vitro study compared delivery through a narrow calibre (8F) feeding tube among four proton pump inhibitors when given by skilled [nurse; (n = 8)] or unskilled [lay; (n = 8)] providers.

METHODS

Following standard instruction, subjects were observed delivering each proton pump inhibitor in a sequential, but random, fashion to evaluate administration quality and time. Delivery was quantified using high-performance liquid chromatography methods and subject preferences were evaluated.

RESULTS

Delivery (%), similar between lansoprazole oral disintegrating tablet (95.7 +/- 3.2) and omeprazole/NaHCO(3) (96.1 +/- 3.0), was both greater for lansoprazole oral disintegrating tablet than esomeprazole in water (88.9 +/- 8.6; P = 0.006) or simplified lansoprazole suspension (86.1 +/- 9.5; P = 0.0001) and omeprazole/NaHCO(3) than esomeprazole in water (P = 0.004) or simplified lansoprazole suspension (P < 0.001), and was not affected by prior subject experience. Quality was higher with both omeprazole/NaHCO(3) and lansoprazole oral disintegrating tablet than simplified lansoprazole suspension. Administration was quicker for lansoprazole oral disintegrating tablet than esomeprazole in water. Subjects preferred lansoprazole oral disintegrating tablet and omeprazole/NaHCO(3).

CONCLUSIONS

When given through an in vitro feeding tube, omeprazole/NaHCO(3) and lansoprazole oral disintegrating tablet lead to greater drug delivery, improved administration quality and higher user satisfaction, than either esomeprazole in water or simplified lansoprazole suspension.

Delivery of esomeprazole magnesium through nasogastric and gastrostomy tubes using an oral liquid vehicle as a suspending agent in vitro

PURPOSE

The optimal delivery medium for esomeprazole magnesium enteric-coated pellets dispersed in various concentrations of Ora-Plus suspension through commonly used nasogastric and gastrostomy tubes using a previously used standardized in vitro protocol was studied.

METHODS

The study was conducted in two phases. In phase A, 60 size 14 French nasogastric tubes were used to compare esomeprazole pellet delivery via tap water or 30, 50, or 70% Ora-Plus concentrations (15 tubes for each). In phase B, tap water and the concentration that yielded the best pellet delivery from phase A were used with the narrower size 8 and shorter size 20 French tubes. In both phases, the appropriate volume of water was added. All capsules were assumed to have 1,240 pellets. At the end of each administration, pellet retention counts were performed.

RESULTS

The results showed excellent delivery of esomeprazole pellets using water as a medium for tube delivery. When compared with tap water as a delivery medium, no differences in pellet retention were observed when 30% and 50% Ora-Plus were used; thus, these Ora-Plus concentrations are feasible alternatives to tap water for nasogastric tube delivery of esomeprazole pellets.

CONCLUSION

Administration of esomeprazole magnesium enteric-coated pellets dispersed in tap water or Ora-Plus through size 14 French nasogastric tubes in vitro delivered over 99% of capsule contents, regardless of the Ora-Plus concentration used. For immediate bedside administration, Ora-Plus at 50% concentration is a feasible alternative to water when delivering the pellets through size 14 French tubes, while 30% Ora-Plus is an alternative to water for all tubes studied.

Proton pump inhibitor formulary considerations in the acutely ill. Part 1: Pharmacology, pharmacodynamics, and available formulations

OBJECTIVE

To review important proton pump inhibitor (PPI) pharmacologic, pharmacokinetic, and pharmacodynamic principles in acutely ill patients, compare PPI formulation options for patients unable to swallow a tablet or capsule, and provide clinicians with guidance when making hospital formulary decisions with this class of agents.

DATA SOURCES

MEDLINE (1966-May 2005) and the Cochrane Library databases were searched using the key words proton pump inhibitor, acid suppression, peptic ulcer disease, gastrointestinal bleeding, stress ulcer prophylaxis, and critical illness. Bibliographies of cited references were reviewed, and a manual search of abstracts from recent gastroenterology, critical care, and surgery scientific meetings was completed.

STUDY SELECTION AND DATA EXTRACTION

All articles identified from the data sources were evaluated, and all information deemed relevant was included for this review.

DATA SYNTHESIS

PPIs have become a mainstay for acute acid suppression in hospitalized patients over other therapeutic options. Various commercially available PPI products are available for administration, either enterally or parenterally, to patients unable to swallow a tablet or capsule. Newer oral PPI formulations offer numerous advantages over older products. The results of studies comparing the pharmacokinetics and pharmacodynamics of different PPI dosage forms and routes of administration are among the factors to consider when making formulary decisions.

CONCLUSIONS

While the introduction of new PPI products has expanded the therapeutic options for acid suppression in acutely ill patients, a number of unresolved questions remain surrounding the interchangeability of these products, the clinical significance of one PPI formulation over the other, and how oral/enteral PPI therapy should be used as step-down therapy after parenteral PPI therapy.

Comparative study and optimisation of the administration mode of three proton pump inhibitors by nasogastric tube

Patients in intensive care often develop stress-induced ulcers. As a preventive measure, proton pump inhibitors (PPIs) are administered by nasogastric tube. However, some PPIs can block the tube. The aim of this study was to compare the behaviour of three PPIs (omeprazole, lanzoprazole and esomeprazole) during the transit of the granules through the tube and to optimise their modes of administration. For each IPP, the experiment was designed to study the influence of four variables: the tube material (silicone or polyurethane), the solvent used to dilute the granules (water or apple juice), the mode of administration (in two or three doses) and the rinse volume (10 or 20 ml). We counted the granules before transit and at the tube outlet, and assayed the active drug ingredient by UV spectrometry. The assay showed complete transit of esomeprazole through the tube, but average losses of omeprazole and lanzoprazole of 39 and 33%, respectively, were observed. No significant improvement was obtained by the variables 'diluent' and 'mode of administration'. The variable 'rinse' had a significant influence. For lanzoprazole, a polyurethane tube allowed recovery of on average 86% of the active ingredient. Esomeprazole is thus the choice PPI for the treatment of patients by nasogastric tube. Using a polyurethane tube and a rinse volume of 20 ml, the administration of lanzoprazole by tube can be considered. Use of omeprazole is not recommended because none of the modes of administration tested ensured that a sufficient concentration of active ingredient reached the stomach.

Proton pump inhibitors for acid suppression in the intensive care unit: Formulary considerations

PURPOSE

The rationale for limiting the proton pump inhibitor (PPI) products included in an institutional formulary, factors to consider when making formulary decisions about PPI products, the results and limitations of cost-effectiveness analyses of PPI therapy in critically ill patients, the role of clinical practice guidelines in improving PPI use in the intensive care setting, and how these guidelines can be developed are discussed.

SUMMARY

Therapeutic interchange may make it possible to limit the number of PPI products included in the formulary and reduce costs without compromising the efficacy or safety of drug therapy. The results of studies comparing the pharmacokinetics, pharmacodynamics, and efficacy of different PPI dosage forms and routes of administration; practical considerations; safety; and costs are among the factors to consider when making formulary decisions. Some of the newer oral PPI products offer advantages over older ones in improved palatability and ease of preparation, storage, and administration. The cost-effectiveness of intravenous (i.v.) PPIs for preventing the recurrence of peptic ulcer bleeding has been demonstrated, but the cost-effectiveness of oral therapy for this indication and both oral and i.v. therapy for preventing stress-related mucosal bleeding has not been well established.

CONCLUSION

Intravenous PPIs are cost-effective for patients at risk for the recurrence of peptic ulcer bleeding. The introduction of new oral PPI products that can be administered as a suspension has expanded the therapeutic options for critically ill patients. The use of clinical practice guidelines can optimize the use of PPIs in the intensive care setting.

Overview of pharmacologic agents for acid suppression in critically ill patients

PURPOSE

The physiology of acid secretion, rationale and goals for acid suppression in critically ill patients, and mechanism of action, pharmacokinetics, pharmacodynamics, and safety of histamine H2-receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) are discussed.

SUMMARY

Acid-suppressant therapy may be used in critically ill patients to prevent stress-related mucosal disease or the recurrence of peptic ulcer bleeding. The intragastric pH goal is 3.5-4.5 and 6 or higher, respectively. H2RAs block only one of three pathways in acid secretion and provide less potent acid suppression than PPIs, which block the final common pathway in acid secretion. In addition, tolerance that occurs with H2RAs does not occur with PPIs. All PPIs work in a similar manner, but differences exist in the pharmacokinetic profiles and binding to the proton pump; the clinical relevance of these differences remains debated. The safety profiles of H2RAs and PPIs are similar; however, the H2RA dose, but not the PPI dose, must be adjusted for patients with renal dysfunction. The risk of drug interactions mediated by cytochrome P-450 enzymes is lower with PPIs than with cimetidine, an H2RA. Several new PPI dosage forms have been introduced, facilitating drug administration in the critical care setting.

CONCLUSION

Both H2RAs and PPIs are safe agents to use for providing acid suppression in critically ill patients, but PPIs offer several potential advantages over H2RAs.

Preventing the gastrointestinal consequences of stress-related mucosal disease

Stress-related mucosal disease (SRMD) and subsequent upper gastrointestinal (GI) bleeding remain significant concerns in critically ill patients and place them at a high risk of death. Even under circumstances in which GI bleeding is detected, it is difficult to control. Thus, appropriate preventative therapy is the key to reducing mortality in patients at risk for stress-related ulceration and bleeding. Although several factors (e.g., hypoperfusion of the GI tract, reflux of bile salts) contribute to the development of stress-related ulceration, acid is presumed to be a major contributor to this disease state. Current preventative treatment strategies use histamine2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs), which suppress acid secretion, and sucralfate, which provides a protective barrier against acid in the GI tract. For the past several years, H2RAs have been preferentially used over PPIs in the hospital setting because H2RAs are available in liquid and intravenous formulations, easing administration problems in the critically ill. However, extemporaneously compounded oral PPI suspensions and the recently approved intravenous formulations of pantoprazole and lansoprazole have eliminated some of the administration issues previously associated with PPIs. Additionally, study data with PPI formulations suggest efficacy in stress ulcer prophylaxis compared with H2RAs. This article provides an overview of SRMD and compares and contrasts the 3 drug classes (i.e., H2RAs, PPIs, and sucralfate) currently used for prevention of this serious complication observed in critically ill patients.