Pharmacokinetics and pharmacodynamics of intravenous midazolam in patients with severe alcoholic cirrhosis

Midazolam Indications and Dosing in Palliative Medicine: Results from a Multinational Survey

Despite sparse evidence and limited guidance on indications, use, and dosing, midazolam is widely used in palliative care. We aimed to describe and compare the use of midazolam in three different countries to improve clinical practice in palliative care. We performed an online survey among palliative care physicians in Norway, Denmark, and the United Kingdom (UK). The focus was indications, dosing, administration, and concomitant drugs. A web-based questionnaire was distributed to members of the respective national palliative medicine associations. The total response rate was 9.4%. Practices in the UK, Norway, and Denmark were overall similar regarding the indications of midazolam for anxiety, dyspnoea, and pain treatment in combination with opioids. However, physicians in the UK used a higher starting dose for anxiety, dyspnoea, and pain treatment compared to Norway and Denmark, as well as a higher maximum dose. Danish physicians preferred, to a higher degree, on-demand midazolam administration. Despite practice similarities in the UK, Norway, and Denmark, differences exist for midazolam dosing and administration in palliative medicine. We demonstrated a lack of consensus on how midazolam should be used in palliative care, setting the stage for future studies on the topic.

Safety of propofol sedation administered by interventional radiologists for radiofrequency ablation in patients with hepatocellular carcinoma

PURPOSE

To evaluate the safety of propofol sedation administered by interventional radiologists during radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Propofol sedation was administered by interventional radiologists in 72 patients (85 procedures, 93 tumors) during RFA for HCC between August 2018 and December 2020. Interventional radiologists equipped with adequate knowledge and skills in sedation and respiratory management were responsible for sedation. Sedation was carefully assessed based on vital signs, including end-tidal carbon dioxide, consciousness status, and bispectral index. The primary endpoint was the incidence of sedation-related complications, which were evaluated separately as respiratory and cardiovascular complications. Secondary endpoints were technical success rate, ablation-related complications, and local tumor control rate. Technical success was defined as completion of ablation in the planned area. Complications were evaluated using the Clavien-Dindo classification. Sedation-related complications, technical success rate, and ablation-related complications were evaluated on a procedure basis, and local tumor control was evaluated on a tumor basis.

RESULTS

Respiratory and cardiovascular complications were observed in eight (8/85, 9.4%) and two (2/85, 2.4%) patients, respectively. Four patients required the jaw thrust maneuver due to glossoptosis, whereas a decrease in oxygen saturation to < 90% was recorded in the other four patients. However, these were temporary, and none required manual ventilation or endotracheal intubation. Bradycardia (< 50 bpm) was detected in two patients; one recovered immediately without treatment, whereas the other rapidly improved after atropine sulfate administration. No severe hypotension (< 80 mmHg) was observed. The technical success rate was 100% (85/85). Grade 3 ablation-related complications were identified in three patients (3/85, 3.5%). The local tumor control rate was 95.7% (89/93).

CONCLUSION

Propofol sedation can be safely administered by interventional radiologists during RFA for HCC. Although it requires special safety considerations, it may be a sedation option during hepatic RFA.

Korean clinical practice guidelines for diagnostic and procedural sedation

Safe and effective sedation depends on various factors, such as the choice of sedatives, sedation techniques used, experience of the sedation provider, degree of sedation-related education and training, equipment and healthcare worker availability, the patient's underlying diseases, and the procedure being performed. The purpose of these evidence-based multidisciplinary clinical practice guidelines is to ensure the safety and efficacy of sedation, thereby contributing to patient safety and ultimately improving public health. These clinical practice guidelines comprise 15 key questions covering various topics related to the following: the sedation providers; medications and equipment available; appropriate patient selection; anesthesiologist referrals for high-risk patients; pre-sedation fasting; comparison of representative drugs used in adult and pediatric patients; respiratory system, cardiovascular system, and sedation depth monitoring during sedation; management of respiratory complications during pediatric sedation; and discharge criteria. The recommendations in these clinical practice guidelines were systematically developed to assist providers and patients in sedation-related decision making for diagnostic and therapeutic examinations or procedures. Depending on the characteristics of primary, secondary, and tertiary care institutions as well as the clinical needs and limitations, sedation providers at each medical institution may choose to apply the recommendations as they are, modify them appropriately, or reject them completely.

Development of a Pharmacokinetic Model That Accounts for the Plasma Concentrations of Conjugated and Unconjugated Bilirubin Observed in a Variety of Disease States

Introduction

For a large variety of liver pathologies, the plasma unconjugated (UB) and conjugated (CB) bilirubin concentrations appear to be coupled. For example, in alcoholic cirrhosis, UB and CB are roughly the same over a large range of total bilirubin, requiring an initial massive increase (about 40-fold) in plasma CB to reach the level of UB and then similar increases in UB and CB as the disease progresses. This coupling has been either unrecognized or ignored and this paper is the first attempt to try to explain it quantitatively in terms of known hepatic cell metabolic and membrane transport properties.

Methods

A simplified pharmacokinetic model is developed and applied to a variety of hyperbilirubinemic pathologies. A central feature of the model is based on the recent observation that double knockout of the rat OATP1A and OATP1B hepatic transporters produces a roughly 400-fold increase in plasma CB, indicating that there is a normal rapid recycling of CB from the cell to the plasma with reuptake via OATP. We use the experimental rat Km of OATP CB transport to show that OATP uptake becomes saturated at relatively low plasma CB concentrations, decreasing uptake, and producing massive (up to 1000-fold) increases in CB in some pathologies. It is assumed that UB and CB are competing for the OATP transporter, producing the increased plasma UB that is observed in "pure" CB pathologies.

Results

The model accurately describes the clinically observed UB and CB for pure UB (Gilbert's, hemolytic anemia) and CB (Dubin-Johnson, Rotor syndrome, biliary atresia) pathologies as well as in cirrhosis.

Conclusion

This model is a preliminary, first attempt to quantitatively describe UB and CB pharmacokinetics. It is hoped that it will stimulate more detailed measurements and analysis.

Liver Cirrhosis Affects the Pharmacokinetics of the Six Substrates of the Basel Phenotyping Cocktail Differently

BACKGROUND

Activities of hepatic cytochrome P450 enzymes (CYPs) are relevant for hepatic clearance of drugs and known to be decreased in patients with liver cirrhosis. Several studies have reported the effect of liver cirrhosis on CYP activity, but the results are partially conflicting and for some CYPs lacking.

OBJECTIVE

In this study, we aimed to investigate the CYP activity in patients with liver cirrhosis with different Child stages (A-C) using the Basel phenotyping cocktail approach.

METHODS

We assessed the pharmacokinetics of the six compounds and their CYP-specific metabolites of the Basel phenotyping cocktail (CYP1A2: caffeine, CYP2B6: efavirenz, CYP2C9: flurbiprofen, CYP2C19: omeprazole, CYP2D6: metoprolol, CYP3A: midazolam) in patients with liver cirrhosis (n = 16 Child A cirrhosis, n = 15 Child B cirrhosis, n = 5 Child C cirrhosis) and matched control subjects (n = 12).

RESULTS

While liver cirrhosis only marginally affected the pharmacokinetics of the low to moderate extraction drugs efavirenz and flurbiprofen, the elimination rate of caffeine was reduced by 51% in patients with Child C cirrhosis. For the moderate to high extraction drugs omeprazole, metoprolol, and midazolam, liver cirrhosis decreased the elimination rate by 75%, 37%, and 60%, respectively, increased exposure, and decreased the apparent systemic clearance (clearance/bioavailability). In patients with Child C cirrhosis, the metabolic ratio (ratio of the area under the plasma concentration-time curve from 0 to 24 h of the metabolite to the parent compound), a marker for CYP activity, decreased by 66%, 47%, 92%, 73%, and 43% for paraxanthine/caffeine (CYP1A2), 8-hydroxyefavirenz/efavirenz (CYP2B6), 5-hydroxyomeprazole/omeprazole (CYP2C19), α-hydroxymetoprolol/metoprolol (CYP2D6), and 1'-hydroxymidazolam/midazolam (CYP3A), respectively. In comparison, the metabolic ratio 4-hydroxyflurbiprofen/flurbiprofen (CYP2C9) remained unchanged.

CONCLUSIONS

Liver cirrhosis affects the activity of CYP isoforms differently. This variability must be considered for dose adjustment of drugs in patients with liver cirrhosis.

CLINICAL TRIAL REGISTRATION

NCT03337945.

Pre-procedural Preparation and Sedation for Gastrointestinal Endoscopy in Patients with Advanced Liver Disease

Gastrointestinal endoscopy in patients with advanced liver disease poses various challenges, a major one being procedural sedation and its associated considerations. While sedation during endoscopy can improve patient comfort, decrease anxiety, and facilitate procedural completion, in patients with advanced liver disease, it is also associated with substantial and unique risks due to alterations in drug metabolism and other factors. As such, the choice of sedative agent(s) and related logistics may require careful inter-disciplinary planning and individualized considerations. Furthermore, a large proportion of agents require dose reductions and particular monitoring of the vital signs, level of consciousness, and other indices. In the present review, we provide a contemporary overview of procedural sedation considerations, commonly used intravenous sedatives, and second-line as well as novel sedatives for gastrointestinal endoscopy in patients with advanced liver disease.

Hepatic impairment as a risk factor of adverse drug reactions

There are a lot of clinical variants of hepatic impairment ranging from asymptomatic increase in transaminases to acute liver failure and fulminant hepatitis. Hepatic impairment is a polietiologic syndrome. According to the epidemiological study conducted in the United States (19982008), the main causes of hepatic impairment were paracetamol overdose (46%), idiopathic liver dysfunction (14%), other drugs (excluding paracetamol, 11%), viral hepatitis B (7%), other infectious and non-infectious diseases with liver damage (except for viral hepatitis) 7%, autoimmune hepatitis (5%), ischemic hepatitis (syn. hypoxic hepatitis, liver infarction) 4%, viral hepatitis A (3%) and Wilson's disease (2%). Hepatic impairment have a direct impact on the pharmacokinetics and pharmacodynamics of drugs decreasing clearance, elimination and excretion of drugs. Also Transjugular intrahepatic porto-systemic shunts, which are often used to treat portal hypertension in patients with liver cirrhosis, can significantly reduce the presystemic elimination of drugs, thereby increasing their absorption. Moreover, in patients with liver cirrhosis, concomitant renal dysfunction also requires an adjustment of the dose of drugs. Correction of pharmacotherapy in accordance to pharmacokinetic and pharmacodynamic changes of drugs ingested by patients with impaired liver function will improve the quality of medical care and reduce the risks of adverse drug reactions.

Review of the Physiology and Anesthetic Considerations for Pleuroscopy/Medical Thoracoscopy

Pleuroscopy or medical thoracoscopy is the second most common utilized procedure after bronchoscopy in the promising field of interventional pulmonology. Its main application is for the diagnosis and management of benign or malignant pleural effusions. Entry into the hemithorax is associated with pain and patient discomfort, whereas concurrently, notable pathophysiologic alterations occur. Therefore, frequently procedural sedation and analgesia is needed, not only to alleviate the patient's emotional stress and discomfort by mitigating the anxiety and minimizing the pain but also for yielding better procedural conditions for the operator. The scope of this review is to present the physiologic derangements occurring in pleuroscopy and compare the various anesthetic techniques and sedative agents that are currently being used in this context.

Liver and Biliary Disease of Pregnancy and Anesthetic Implications: A Review

Liver and biliary disease complicates pregnancy in varying degrees of severity to the mother and fetus, and anesthesiologists may be asked to assist in caring for these patients before, during, and after birth of the fetus. Therefore, it is important to be familiar with how different liver diseases impact the pregnancy state. In addition, knowing symptoms, signs, and laboratory markers in the context of a pregnant patient will lead to faster diagnosis and treatment of such patients. This review article discusses changes in physiology of parturients, patients with liver disease, and parturients with liver disease. Next, general treatment of parturients with acute and chronic liver dysfunction is presented. The article progresses to specific liver diseases with treatments as they relate to pregnancy. And finally, important aspects to consider when anesthetizing parturients with liver disease are discussed.

Effect of Liver Cirrhosis on the Pharmacokinetics, Metabolism, and Tolerability of Daridorexant, A Novel Dual Orexin Receptor Antagonist

BACKGROUND AND OBJECTIVE

Daridorexant is a dual orexin receptor antagonist in clinical development for insomnia. As daridorexant is cleared mainly via cytochrome P450 (CYP) 3A4, the effect of hepatic impairment on the pharmacokinetics (PK), metabolism, and tolerability of daridorexant was evaluated. Sleep disorders are common in patients with liver cirrhosis and, therefore, sleep-promoting drugs with a better tolerability than currently available would be preferable, a premise that dual orexin receptor antagonists may fulfill.

METHODS

This was a single-dose, open-label, phase I study. Subjects with mild (Child-Pugh A, N = 8) or moderate (Child-Pugh B, N = 8) liver cirrhosis and matched healthy control subjects (N = 8) received 25 mg of daridorexant orally. Blood samples were collected for 72 h post-dose for PK assessments of daridorexant and three major metabolites.

RESULTS

Compared with healthy subjects, patients showed a decrease in total daridorexant area under the plasma concentration-time curve from zero to infinity (AUC_0-inf) and maximum plasma concentration with a geometric mean ratio (GMR, 90% confidence interval [CI]) of 0.51 (0.28-0.92) and 0.50 (0.35-0.72) in Child-Pugh A and 0.74 (0.39-1.41) and 0.42 (0.29-0.60) in Child-Pugh B patients, respectively. Furthermore, the median time to reach maximum plasma concentration was slightly delayed (1.0 h [90% CI 0.0-2.0] in Child-Pugh A patients and 0.5 h [90% CI 0.0-1.5] in Child-Pugh B patients), while for Child-Pugh B patients, a doubling in half-life was observed (GMR [90% CI]: 2.09 [1.32-3.30]). Considering the high plasma protein binding (> 99%) and a 1.9-fold to 2.3-fold increase in the unbound fraction in patients, the PK of unbound daridorexant was also assessed. Compared with healthy subjects, Child-Pugh B patients had a higher AUC_0-inf (GMR [90% CI] 1.60 [0.93-2.73]), a lower apparent plasma clearance (GMR [90% CI] 0.63 [0.37-1.07]), and the same doubling in the half-life observed for total daridorexant, whereas maximum plasma concentration and apparent volume of distribution were not different. Unbound daridorexant PK in Child-Pugh A patients did not differ from healthy subjects. In addition, the metabolic ratios (parent to metabolite), i.e., a marker of CYP 3A4 activity, of the two most abundant daridorexant metabolites were higher in patients with liver cirrhosis compared with healthy subjects. All treatment-emergent adverse events were transient and of mild or moderate intensity and no other treatment-related effects were apparent.

CONCLUSIONS

No safety issue of concern was detected following administration of 25 mg of daridorexant in the study population. Moderate liver cirrhosis causes impaired hepatic clearance of unbound daridorexant, which prolongs the half-life. A 25-mg dose of daridorexant should, therefore, not be exceeded in Child-Pugh B patients. A dose adjustment is not required in Child-Pugh A patients, while avoidance of daridorexant in patients with Child-Pugh C cirrhosis is recommended.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03713242.

Management of status epilepticus in patients with liver or kidney disease: a narrative review

Introduction: Status epilepticus (SE) is a neurologic and medical emergency with significant related morbidity and mortality. Hepatic or renal dysfunction can considerably affect the pharmacokinetics of drugs used for SE through a variety of direct or indirect mechanisms.Areas Covered: This review aims to focus on the therapeutic management of SE in patients with hepatic or renal impairment, highlighting drugs' selection and dose changes that may be necessary due to altered drug metabolism and excretion. The references for this review were identified by searches of PubMed and Google Scholar until May 2020.Expert opinion: According to literature evidence and clinical experience, in patients with renal disease, the authors suggest considering lorazepam as the drug of choice in pre-hospital and intra-hospital early-stage SE, phenytoin in definite SE, propofol in refractory or super-refractory SE. In patients with liver disease, the authors suggest the use of lorazepam as drug of choice in pre-hospital and intra-hospital early-stage SE, lacosamide in definite SE, propofol in refractory or super-refractory SE. A list of preferred drugs for all SE stages is provided.

Propofol vs midazolam sedation for elective endoscopy in patients with cirrhosis: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Patients with cirrhosis frequently require sedation for elective endoscopic procedures. Several sedation protocols are available, but choosing an appropriate sedative in patients with cirrhosis is challenging.

AIM

To conduct a systematic review and meta-analysis to compare propofol and midazolam for sedation in patients with cirrhosis during elective endoscopic procedures in an attempt to understand the best approach.

METHODS

This systematic review and meta-analysis was conducted using the PRISMA guidelines. Electronic searches were performed using MEDLINE, EMBASE, Central Cochrane, LILACS databases. Only randomized control trials (RCTs) were included. The outcomes studied were procedure time, recovery time, discharge time, and adverse events (bradycardia, hypotension, and hypoxemia). The risk of bias assessment was performed using the Revised Cochrane Risk-of-Bias tool for randomized trials (RoB-2). Quality of evidence was evaluated by GRADEpro. The meta-analysis was performed using Review Manager.

RESULTS

The search yielded 3,576 records. Out of these, 8 RCTs with a total of 596 patients (302 in the propofol group and 294 in the midazolam group) were included for the final analysis. Procedure time was similar between midazolam and propofol groups (MD: 0.25, 95%CI: -0.64 to 1.13, P = 0.59). Recovery time (MD: -8.19, 95%CI: -10.59 to -5.79, P < 0.00001). and discharge time were significantly less in the propofol group (MD: -12.98, 95%CI: -18.46 to -7.50, P < 0.00001). Adverse events were similar in both groups (RD: 0.02, 95%CI: 0-0.04, P = 0.58). Moreover, no significant difference was found for bradycardia (RD: 0.03, 95%CI: -0.01 to 0.07, P = 0.16), hypotension (RD: 0.03, 95%CI: -0.01 to 0.07, P = 0.17), and hypoxemia (RD: 0.00, 95%CI: -0.04 to 0.04, P = 0.93). Five studies had low risk of bias, two demonstrated some concerns, and one presented high risk. The quality of the evidence was very low for procedure time, recovery time, and adverse events; while low for discharge time.

CONCLUSION

This systematic review and meta-analysis based on RCTs show that propofol has shorter recovery and patient discharge time as compared to midazolam with a similar rate of adverse events. These results suggest that propofol should be the preferred agent for sedation in patients with cirrhosis.

Midazolam: an essential palliative care drug

Midazolam is a commonly used benzodiazepine in palliative care and is considered one of the four essential drugs needed for the promotion of quality care in dying patients. Acting on the benzodiazepine receptor, it promotes the action of gamma-aminobutyric acid. Gamma-aminobutyric acid action promotes sedative, anxiolytic, and anticonvulsant properties. Midazolam has a faster onset and shorter duration of action than other benzodiazepines such as diazepam and lorazepam lending itself to greater flexibility in dosing than other benzodiazepines. The kidneys excrete midazolam and its active metabolite. Metabolism occurs in the liver by the P450 system. This article examines the pharmacology, pharmacodynamics, and clinical uses of midazolam in palliative care.

Midazolam: Safety of use in palliative care: A systematic critical review

PURPOSE

The undesired effects of midazolam can be life-threatening. This paper delineates the findings related to the pharmacokinetics, adverse effects and drug-drug interactions as well as associated therapeutic implications for safe midazolam use.

METHODS

A systematic review of literature was conducted.

RESULTS

The pharmacokinetics of midazolam depends on hepatic and renal functions, fat tissue mass, route and duration of administration, as well as potential drug-drug interactions. Palliative care patients constitute a high-risk group prone to side effects of drugs, due to polytherapy and multi-organ failure.

CONCLUSION

Midazolam is one of three most frequently administered drugs in palliative care. The indications for its use include anxiety, dyspnea, seizures, vomiting refractory to treatment, agitation, myoclonus, status epilepticus, restlessness, delirium, pruritus, hiccups, insomnia, analgosedation, palliative sedation and preventing or counteracting undesired effects of ketamine.

Safety and effectiveness of midazolam for cirrhotic patients undergoing endoscopic variceal ligation

BACKGROUND/AIMS

Endoscopic variceal ligation (EVL) is an established treatment for esophageal variceal bleeding. Midazolam (MDZ) is most commonly used for sedation during endoscopic procedures. However, adverse events (AEs) may occur more frequently in patients with cirrhosis due to altered MDZ metabolism.

MATERIALS AND METHODS

We retrospectively reviewed the records of 325 patients with cirrhosis who received EVL.

RESULTS

No significant differences were found in treatment outcome and procedure time among 151 patients in the MDZ group and 169 patients in the non-MDZ group. Desaturation (23.2% vs. 7.7%, p<0.01), bradycardia (22.5% vs. 17.2%, p=0.03), and hepatic encephalopathy (HE) (6.6% vs. 0.6%, p<0.01) were more common in the MDZ group than in the non-MDZ group. Logistic regression analyses revealed that an Eastern Cooperative Oncology Group (ECOG) score of ≥2 (p<0.01) and the use of MDZ (p<0.01) were associated with the development of overall AEs. An ECOG score of ≥2 (p=0.01), high serum creatinine level (p=0.02), and the use of MDZ (p<0.01) were significant risk factors for HE.

CONCLUSION

Extreme caution should be taken when sedating patients with cirrhosis receiving EVL due to the AEs associated with the use of MDZ.

Nonalcoholic Fatty Liver Disease and Diabetes Are Associated with Decreased CYP3A4 Protein Expression and Activity in Human Liver

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease in the Western population. We investigated the association of nonalcoholic fatty liver disease (NAFLD) and diabetes mellitus on CYP3A4 activity in human liver tissue from brain dead donors ( n = 74). Histopathologically graded livers were grouped into normal ( n = 24), nonalcoholic fatty liver (NAFL, n = 26), and nonalcoholic steatohepatitis (NASH, n = 24) categories. The rate of conversion of midazolam to its 1-hydroxy metabolite was used to assess in vitro CYP3A4 activity in human liver microsomes (HLM). A proteomics approach was utilized to quantify the protein expression of CYP3A4 and related enzymes. Moreover, a physiologically based pharmacokinetic (PBPK) model was developed to allow prediction of midazolam concentration in NAFL and NASH livers. CYP3A4 activity in NAFL and NASH was 1.9- and 3.1-fold ( p < 0.05) lower than normal donors, respectively. Intrinsic clearance (CLint) was 2.7- ( p < 0.05) and 4.1-fold ( p < 0.01) lower in donors with NAFL and NASH, respectively. CYP3A4 protein expression was significantly lower in NAFL and NASH donors ( p < 0.05) and accounted for significant midazolam hydroxylation variability in a multiple linear regression analysis (β = 0.869, r² = 0.762, P < 0.01). Diabetes was also associated with decreased CYP3A4 activity and protein expression. Both midazolam CLint and CYP3A4 protein abundance decreased significantly with increase in hepatic fat accumulation. Age and gender did not exhibit any significant association with the observed alterations. Predicted midazolam exposure was 1.7- and 2.3-fold higher for NAFL and NASH, respectively, which may result in a longer period of sedation in these disease-states. Data suggests that NAFLD and diabetes are associated with the decreased hepatic CYP3A4 activity. Thus, further evaluation of clinical consequences of these findings on the efficacy and safety of CYP3A4 substrates is warranted.

Changes in cytochrome P450s-mediated drug clearance in patients with hepatocellular carcinoma in vitro and in vivo: a bottom-up approach

Hepatocellular carcinoma (HCC) accompanied by severe liver dysfunction is a serious disease, which results in altered hepatic clearance. Generally, maintenance doses depend upon drug clearance, so individual dosage regimens should be customized for HCC patients based on the condition of patients. Based on clearance of CYP isoform-specific substrates at the microsomal level (CL_M), microsomal protein per gram of liver (MPPGL), liver weight, hepatic blood flow, hepatic clearance values (CL_H) for 10 CYPs in HCC patients (n=102) were extrapolated using a predictive bottom-up pharmacokinetic model. Compared with controls, the CL_M values for CYP2C9, 2D6, 2E1 were significantly increased in HCC patients. Additionally, CYP1A2, 2C8, 2C19 CL_M values decreased while the values for CYP2A6, 2B6, 3A4/5 were unchanged. The MPPGL values in HCC tissues were significantly reduced. CL_H values of HCC patients for CYP1A2, 2A6, 2B6, 2C8, 2C19, and 3A4/5 were significantly reduced, while this for CYP2E1 were markedly increased and those for CYP2C9 and 2D6 did not change. Moreover, disease (fibrosis and cirrhosis) and polymorphisms of the CYP genes have influenced the CL_H for some CYPs. Prediction of the effects of HCC on drug clearance may be helpful for the design of clinical studies and the clinical management of drugs in HCC patients.

Ultrathin disposable gastroscope for screening and surveillance of gastroesophageal varices in patients with liver cirrhosis: a prospective comparative study

BACKGROUND AND AIMS

This study aims to evaluate the role of unsedated, ultrathin disposable gastroscopy (TDG) against conventional gastroscopy (CG) in the screening and surveillance of gastroesophageal varices (GEVs) in patients with liver cirrhosis.

METHOD

Forty-eight patients (56.4 ± 1.3 years; 38 male, 10 female) with liver cirrhosis referred for screening (n = 12) or surveillance (n = 36) of GEVs were prospectively enrolled. Unsedated gastroscopy was initially performed with TDG, followed by CG with conscious sedation. The 2 gastroscopies were performed by different endoscopists blinded to the results of the previous examination. Video recordings of both gastroscopies were validated by an independent investigator in a random, blinded fashion. Endpoints were accuracy and interobserver agreement of detecting GEVs, safety, and potential cost saving.

RESULTS

CG identified GEVs in 26 (54%) patients, 10 of whom (21%) had high-risk esophageal varices (HREV). Compared with CG, TDG had an accuracy of 92% for the detection of all GEVs, which increased to 100% for high-risk GEVs. The interobserver agreement for detecting all GEVs on TDG was 88% (κ = 0.74). This increased to 94% (κ = 0.82) for high-risk GEVs. There were no serious adverse events.

CONCLUSIONS

Unsedated TDG is safe and has high diagnostic accuracy and interobserver reliability for the detection of GEVs. The use of clinic-based TDG would allow immediate determination of a follow-up plan, making it attractive for variceal screening and surveillance programs. (Clinical trial (ANZCTR) registration number: ACTRN12616001103459.).

Pharmacokinetics cannot explain the increased effective dose requirement for morphine and midazolam in rats during their extended administration alone or in combination

Objectives

Chronic administration of morphine and midazolam, alone or in combination, can induce tolerance to their effects. Data showed that co-administration of morphine and midazolam increased effective dose requirement of morphine, exceeding that observed with morphine alone.

Methods

To elucidate the pharmacokinetic component to the tolerance, we administered midazolam (2 mg/kg) and morphine (10 mg/kg) alone or their combination daily to rats for 12 days followed by a pharmacokinetic study on day 13. On the study day, each animal received a single bolus dose of 5 mg/kg morphine, and 2 mg/kg of midazolam 30 s later. Multiple blood samples were obtained for 6 h. Plasma drug concentrations were assayed by mass spectrometry optimized for small samples.

Key findings

Mean morphine clearance was as follows: 22.2, 27.2, 26.0 and 23.4 l/h per kg in the saline–saline, saline–midazolam, saline–morphine and midazolam–morphine groups, respectively. Corresponding midazolam clearances were 32.8, 23.0, 22.2 and 31.1 l/h per kg. ANOVA indicated no significant differences among the four groups in the clearances, half-lives, and volumes of distribution. Morphine and midazolam clearances were significantly correlated (R2 = 0.48, P &lt; 0.001).

Conclusions

This animal model suggests that altered pharmacokinetics cannot explain tolerance evidenced as increased dose requirement for morphine or midazolam, when administered alone or combination, for extended periods.

Effect of hepatic function on the EC50 of midazolam and the BIS50 at the time of loss of consciousness

OBJECTIVE

To explore the effect of hepatic function on loss of consciousness (LOC) and bispectral index (BIS) during sedation with midazolam (MDZ).

METHODS

Forty-five patients were assigned to three groups according to their liver function. Thirty of these patients with diagnoses of cholelithiasis were scheduled laparoscopic cholecystectomy, including 15 patients with normal liver function (normal group), and 15 patients with moderately abnormal liver function based on the results of ultrasonic diagnosis of a moderately fatty liver and elevated alanine transaminase levels of less than three times normal (moderate group). The other 15 patients with end-stage liver disease (severe group) underwent liver transplantation. Each patient was administered MDZ by way of target-controlled infusion to increase the concentration gradually. At the time of LOC, the BIS was recorded and a blood sample was withdrawn for measurement of the concentration of MDZ. The concentration of MDZ (EC50) and the BIS value (BIS50) at which 50% of patients lose consciousness were calculated using logistic regression.

RESULTS

At the time of LOC, the EC50 of MDZ and the BIS50 were similar in the normal and moderate groups (P>0.05). LOC occurred at a lower EC50 of MDZ and at a higher BIS50 in the severe group, compared with the normal and moderate groups (P<0.01).

CONCLUSIONS

Patients with end-stage liver disease were more sensitive to MDZ and this affected the prediction of their time of LOC following MDZ administration. There were no changes in response in patients with moderately abnormal hepatic function.

CYP3A activity in severe liver cirrhosis correlates with Child-Pugh and model for end-stage liver disease (MELD) scores

AIMS

Impaired liver function often necessitates drug dose adjustment to avoid excessive drug accumulation and adverse events, but a marker for the extent of the required adjustment is lacking. The aim of this study was to investigate whether Child-Pugh (CP) and model for end-stage liver disease (MELD) scores correlate with drug clearance.

METHODS

Midazolam was used as a CYP3A probe and its pharmacokinetics were analyzed in 24 patients with mild to severe liver cirrhosis (n = 4, 10 and 10 with CP class A, B and C, respectively) and six patients without liver disease.

RESULTS

Both scores correlated well with unbound midazolam clearance (CLu ), unbound midazolam fraction and half-life (all P < 0.01), whereas the unbound steady-state volume of distribution was not significantly changed. In patients with severe liver cirrhosis unbound midazolam clearance was only 14% of controls (CP C: CLu = 843 ± 346 l  h(-1), MELD ≥ 15: CLu = 805 ± 474 l  h(-1), controls: CLu = 5815 ± 2649 l  h(-1), P < 0.01).

CONCLUSION

The correlation with unbound midazolam clearance suggests that either score predicts the metabolic capacity of CYP3A, the most relevant drug metabolizing enzyme subfamily in humans.

Pharmacokinetic of antiepileptic drugs in patients with hepatic or renal impairment

Many factors influence choice of antiepileptic drugs (AEDs), including efficacy of the drug for the indication (epilepsy, neuropathic pain, affective disorder, migraine), tolerability, and toxicity. The first-generation AEDs and some newer AEDs are predominately eliminated by hepatic metabolism. Other recent AEDs are eliminated by renal excretion of unchanged drug or a combination of hepatic metabolism and renal excretion. The effect of renal and hepatic disease on the dosing will depend on the fraction of the AED eliminated by hepatic and/or renal excretion, the metabolic isozymes involved, as well as the extent of protein binding, if therapeutic drug monitoring is used. For drugs that are eliminated by renal excretion, methods of estimating creatinine clearance can be used to determine dose adjustments. For drugs eliminated by hepatic metabolism, there are no specific markers of liver function that can be used to provide guidance in dosage adjustments. Based on studies with probe drugs, the hepatic metabolic enzymes are differentially affected depending on the cause and severity of hepatic disease, which can aid in predicting dose adjustment when clinical data are not available. Several AEDs are also associated with laboratory markers of mild hepatic dysfunction and, rarely, more severe hepatic injury. In contrast, the risk of renal injury from AEDs is generally low. In general, co-morbid hepatic or renal diseases influence the decision for the selection of an AED. For some patients dosing changes to their existing AEDs may be appropriate. For others, a change to another AED may be a better option.

Benzodiazepine-associated hepatic encephalopathy significantly increased healthcare utilization and medical costs of Chinese cirrhotic patients: 7-year experience

BACKGROUND AND OBJECTIVES

In cirrhosis, hypersensitivity to benzodiazepines (BZD) and precipitating hepatic encephalopathy (HE) have been reported. The aim of this study was to evaluate the safety, economic impact and modifiable factors that are associated with the excess risk of BZD-associated HE in cirrhotic patients.

METHODS

Between July 2005 and March 2012, 1,612 Chinese cirrhotic patients with and without using long-t 1/2-BZD or short-t 1/2-BZD were enrolled and followed up for 6 months.

RESULTS

Among BZD users, the per-person HE-related healthcare utilization and medical costs were found to have progressively increased from 2005 to 2012. Cirrhotic BZD users had a higher percentage of smoking, alcohol drinking, simultaneous consumption of non-BZD drugs, and had a higher incidence of non-cirrhotic chronic illness than non-BZD users. Multivariate analysis indicated that hypoalbuminemia (<3 g/dL), long-acting (t 1/2 > 12-h), high-dosage (>1.5 defined daily dose equivalents) and long-duration (>2-months) BZD use, carrier of variant genotypes (AG + GG) of GABRA 1 (rs2290732) and having the wild genotype (TT) of GABRG 2 (rs211037) were significant predictors of the development of BZD-associated HE in cirrhotic patients. Additionally, synergistic effects of the above significant predictors on BZD-associated HE risk could be identified.

CONCLUSIONS

Our study confirms the clinical and economic impact of BZD-associated HE in cirrhotic BZD-users. Accordingly, extra caution is needed when treating cirrhotic BZD users with the above risk factors in order to avoid the BZD-associated HE in cirrhotic patients.

Monitoring and managing hepatic disease in anaesthesia

Patients with liver disease have multisystem organ dysfunction that leads to physiological perturbations ranging from hyperbilirubinaemia of no clinical consequence to severe coagulopathy and metabolic disarray. Patient-specific risk factors, clinical scoring systems, and surgical procedures stratify perioperative risk for these patients. The anaesthetic management of patients with hepatic dysfunction involves consideration of impaired drug metabolism, hyperdynamic circulation, perioperative hypoxaemia, bleeding, thrombosis, and hepatic encephalopathy.

Review article: prescribing medications in patients with cirrhosis - a practical guide

BACKGROUND

Most drugs have not been well studied in cirrhosis; recommendations on safe use are based largely on experience and/or expert opinion, with dosing recommendations often based on pharmacokinetic (PK) changes.

AIM

To provide a practical approach to prescribing medications for cirrhotic patients.

METHODS

An indexed MEDLINE search was conducted using keywords cirrhosis, drug-induced liver injury, pharmacodynamics (PDs), PKs, drug disposition and adverse drug reactions. Unpublished information from the Food and Drug Administration and industry was also reviewed.

RESULTS

Most medications have not been adequately studied in cirrhosis, and specific prescribing information is often lacking. Lower doses are generally recommended based on PK changes, but data are limited in terms of correlating PD effects with the degree of liver impairment. Very few drugs have been documented to have their hepatotoxicity potential enhanced by cirrhosis; most of these involve antituberculosis or antiretroviral agents used for HIV or viral hepatitis. Paracetamol can be used safely when prescribed in relatively small doses (2-3 g or less/day) for short durations, and is recommended as first-line treatment of pain. In contrast, NSAIDs should be used cautiously (or not at all) in advanced cirrhosis. Proton pump inhibitors have been linked to an increased risk of spontaneous bacterial peritonitis (SBP) in cirrhosis and should be used with care.

CONCLUSIONS

Most drugs can be used safely in cirrhosis, including those that are potentially hepatotoxic, but lower doses or reduced dosing frequency is often recommended, due to altered PKs. Drugs that can precipitate renal failure, gastrointestinal bleeding, SBP and encephalopathy should be identified and avoided.

Safety and effectiveness of low-dose propofol sedation during and after esophagogastroduodenoscopy in child A and B cirrhotic patients

BACKGROUND

Effective and safe sedation for patients with liver cirrhosis is problematic.

AIM

To examine the safety and effectiveness of low-dose propofol sedation during and after esophagogastroduodenoscopy (EGD) in cirrhotic patients.

METHODS

Study 1 was a prospective study in cirrhotic patients who underwent diagnostic EGD under propofol sedation. Propofol was given by bolus injection with an age-adjusted standard protocol consisting of 40 mg for patients <70 years, 30 mg for patients aged 70-89 years; additional injections of 20 mg propofol were given up to a maximum of 120 mg. The principal parameter was the occurrence of adverse events within 24 h after EGD. Secondary parameters included successful procedures, complications, and full recovery within 60 min. In Study 2, the residual effects of propofol were evaluated using a driving simulator and blood propofol concentrations in a subset of cirrhotic patients undergoing EGD and compared with healthy individuals. The principal parameter was driving ability.

RESULTS

Study 1: Consecutive cirrhotic patients were entered and all 163 successfully completed EGD. The mean dose of propofol was 46 mg (range 30-120 mg). No complications occurred. Full recovery had occurred in 100 % 60 min after the procedure. No adverse events occurred within 24 h after EGD. Study 2: There were no significant differences in blood propofol levels between cirrhotic patients (n = 21) and healthy individuals (n = 20) after sedation. In cirrhotic patients, there was no deterioration in driving ability as compared with healthy individuals.

CONCLUSION

Low-dose propofol sedation provided safe and effective sedation for EGD in cirrhotic patients with rapid recovery.

Randomized controlled trial for endoscopy with propofol versus midazolam on psychometric tests and critical flicker frequency in people with cirrhosis

BACKGROUND AND AIM

People with cirrhosis are at increased risk of development of complications related to sedation. The aim of the present study was to compare the effects of sedation for upper gastrointestinal endoscopy (UGIE) with propofol and midazolam on psychometric tests and critical flicker frequency (CFF) in people with cirrhosis.

METHODS

A total of 127 people with cirrhosis were randomized into three groups: propofol group (n = 40), midazolam group (n = 42) and no sedation (n = 45). All patients underwent CFF test and combination of psychometry (number connection test-A and B [NCT-A,B]; digit symbol test [DST], line tracing test [LTT] and serial dotting test [SDT]) at baseline and at 2 h post-endoscopy. CFF was done at 30 min and repeated every 30 min for 2 h.

RESULTS

In the propofol group there was no deterioration in psychometry (NCT-A [55.6 ± 18.7 vs 56.4 ± 19.0 s], NCT-B [98.2 ± 35.1 vs 97.8 ± 34.6 s], DST [26.7 ± 5.7 vs 26.3 ± 5.3], LTT [112.9 ± 35.7 vs 113.7 ± 36.6 s], SDT [94.6 ± 34.1 vs 95.2 ± 34.5 s]). Significant deterioration from baseline (39.8 ± 2.9 Hz) was seen in CFF at 30 min (38.8 ± 2.3 Hz) and 1 h (39.2 ± 2.4 Hz), P = 0.01 but no difference thereafter. In the midazolam group, significant deterioration was observed on psychometry (NCT-A [56.0 ± 18.5 vs 60.4 ± 19.8 s], NCT-B [99.9 ± 29.1 vs 105.9.6 ± 30.3 s], DST [26.1 ± 4.7 vs 25.2 ± 4.3], LTT [129.1 ± 34.5 vs 132.9 ± 35.4 s], SDT [95.6 ± 34.2]). No deterioration was observed in psychometry and CFF in people with cirrhosis without sedation.

CONCLUSIONS

Propofol sedation for UGIE was associated with earlier recovery compared with midazolam, which causes deterioration of psychometric tests and CFF for a longer time in comparison with propofol.

Update of endoscopy in liver disease: More than just treating varices

The management of complications in liver disease is often complex and challenging. Endoscopy has undergone a period of rapid expansion with numerous novel and specialized endoscopic modalities that are of increasing value in the investigation and management of the patient with liver disease. In this review, relevant literature search and expert opinions have been used to provide a brief overview and update of the current endoscopic management of patients with liver disease and portal hypertension. The main areas covered are safety of endoscopy in patients with liver disease, the use of standard endoscopy for the treatment of varices and the role of new endoscopic modalities such as endoscopic ultrasound, esophageal capsule, argon plasma coagulation, spyglass and endomicroscopy in the investigation and treatment of liver-related gastrointestinal and biliary pathology. It is clear that the role of the endoscopy in liver disease is well beyond that of just treating varices. As the technology in endoscopy expands, so does the role of the endoscopist in liver disease.

Sedation during upper GI endoscopy in cirrhotic outpatients: a randomized, controlled trial comparing propofol and fentanyl with midazolam and fentanyl

BACKGROUND

Patients with liver cirrhosis frequently undergo diagnostic or therapeutic upper GI endoscopy (UGIE), and the liver disease might impair the metabolism of drugs usually administered for sedation.

OBJECTIVE AND SETTING

To compare sedation with a combination of propofol plus fentanyl and midazolam plus fentanyl in cirrhotic outpatients undergoing UGIE.

DESIGN

A prospective, randomized, controlled trial was conducted between February 2008 and February 2009.

MAIN OUTCOMES MEASUREMENTS

Efficacy (proportion of complete procedures using the initial proposed sedation scheme), safety (occurrence of sedation-related complications), and recovery time were measured.

RESULTS

Two hundred ten cirrhotic patients referred for UGIE were randomized to 2 groups: midazolam group (0.05 mg/kg plus fentanyl 50 μg intravenously) or propofol group (0.25 mg/kg plus fentanyl 50 μg intravenously). There were no differences between groups regarding age, sex, weight, etiology of cirrhosis, and Child-Pugh or American Society of Anesthesiologists classification. Sedation with propofol was more efficacious (100% vs 88.2%; P < .001) and had a shorter recovery time than sedation with midazolam (16.23 ± 6.84 minutes and 27.40 ± 17.19 minutes, respectively; P < .001). Complication rates were similar in both groups (14% vs 7.3%; P = .172).

LIMITATIONS

Single-blind study; sample size.

CONCLUSION

Both sedation schemes were safe in this setting. Sedation with propofol plus fentanyl was more efficacious with a shorter recovery time compared with midazolam plus fentanyl. Therefore, the former scheme is an alternative when sedating cirrhotic patients undergoing UGIE.

Blood concentrations of midazolam in status epilepticus using an appropriate condition of HPLC

BACKGROUND

The aim of the present study was to determine an index to evaluate the efficacy and safety of midazolam (MDZ) to treat status epilepticus (SE). An original system was therefore developed to measure blood concentrations of MDZ and 1-hydroxymidazolam (1-OHMDZ) as the main metabolite on high-performance liquid chromatography.

METHODS

This system was established through inspection of chromatograms, calibration curves and coefficient of correlations of MDZ. The clinical course of 11 SE patients, ranging from 4 months to 10 years of age, are described. These patients were treated with MDZ and measured at each blood concentration of MDZ. Moreover, patients were evaluated on cranial computed tomography and magnetic resonance imaging and video electroencephalogram (EEG), and it was determined that their seizures disappeared in accordance with the disappearance of convulsions and interictal EEG findings.

RESULTS

Reproducibility was good with this system. The standard curves of MDZ and 1-OHMDZ were almost straight, and the correlation coefficients of MDZ and 1-OHMDZ were r = 0.9999 and r = 0.9998, respectively. The convulsions in nine of 11 SE patients disappeared without side-effects and the blood concentrations of MDZ in all the patients were measured. The mean peak blood concentrations of MDZ and 1-OHMDZ were higher than those reported in other studies.

CONCLUSIONS

The clinical utility of this system has been demonstrated. An index to evaluate the efficacy and safety of MDZ is necessary, and MDZ blood concentrations measured on the present original precise measuring system could help in establishing a plan to successfully treat SE.

A semi-mechanistic model to predict the effects of liver cirrhosis on drug clearance

BACKGROUND AND OBJECTIVE

Liver cirrhosis is characterized by a decrease in functional hepatocytes, lowered circulating levels of plasma proteins and alterations in blood flow due to the development of portacaval shunts. Depending on the interplay between these parameters and the characteristics of an administered drug, varying degrees of impaired systemic clearance and first-pass metabolism are anticipated. The Simcyp Population-based ADME Simulator has already been used successfully to incorporate genetic, physiological and demographic attributes of certain subgroups within healthy populations into in vitro-in vivo extrapolation (IVIVE) of xenobiotic clearance. The objective of this study was to extend population models to predict systemic and oral drug clearance in relation to the severity of liver cirrhosis.

METHODS

Information on demographics, changes in hepatic blood flow, cytochrome P450 enzymes, liver size, plasma protein binding and renal function was incorporated into three separate population libraries. The latter corresponded to Child-Pugh scores A (mild), B (moderate) and C (severe) liver cirrhosis. These libraries, together with mechanistic IVIVE within the Simcyp Simulator, were used to predict the clearance of intravenous and oral midazolam, oral caffeine, intravenous and oral theophylline, intravenous and oral metoprolol, oral nifedipine, oral quinidine, oral diclofenac, oral sildenafil, and intravenous and oral omeprazole. The simulated patients matched the clinical studies as closely as possible with regard to demographics and Child-Pugh scores. Predicted clearance values in both healthy control and liver cirrhosis populations were compared with observed values, as were the fold increases in clearance values between these populations.

RESULTS

There was good agreement (lack of statistically significant difference, two-tailed paired t-test) between observed and predicted clearance ratios, with the exception of those for two studies of intravenous omeprazole. Predicted clearance ratios were within 0.8- to 1.25-fold of observed ratios in 65% of cases (range 0.34- to 2.5-fold).

CONCLUSION

The various drugs that were studied showed different changes in clearance in relation to disease severity, and a 'one size fits all' solution does not exist without considering the multiple sources of the changes. Predictions of the effects of liver cirrhosis on drug clearance are of potential value in the design of clinical studies during drug development and, clinically, in the assessment of likely dosage adjustment.

Endoscopic sedation of patients with chronic liver disease

Endoscopic procedures are often necessary in patients with chronic liver disease. The preprocedure evaluation of such patients should include an assessment of hepatic synthetic function and identification of neuropsychiatric findings suggestive of hepatic encephalopathy. It may be possible, in some cases, to perform diagnostic esophagogastroduodenoscopy without administration of sedation; this is desirable to eliminate the risks of sedation, especially encephalopathy. Nonetheless, most patients undergoing upper and lower endoscopy require sedation. Currently, the use of propofol is preferred to benzodiazepines and opioids for endoscopic sedation of patients with advanced liver disease due to its short biologic half-life and low risk of provoking hepatic encephalopathy. In appropriately selected patients, gastroenterologist-directed propofol administration seems safe.

Propofol sedation for upper gastrointestinal endoscopy in patients with liver cirrhosis as an alternative to midazolam to avoid acute deterioration of minimal encephalopathy: a randomized, controlled study

OBJECTIVE

Midazolam sedation for upper gastrointestinal (GI) endoscopy exacerbates minimal hepatic encephalopathy (HE) in patients with liver cirrhosis, therefore an alternative drug regimen for these patients is warranted. The aim of this randomized, controlled study was to assess whether the use of the short-acting propofol as a sedative for GI endoscopy could prevent the exacerbation of minimal HE in patients with liver cirrhosis.

MATERIAL AND METHODS

The study comprised patients with liver cirrhosis without clinical HE who had undergone upper GI endoscopy for therapeutic purposes (intended variceal band ligation). Sixty patients were randomly assigned into two groups to receive propofol (n=40) or midazolam (n=20) for upper GI endoscopy. The study groups were matched for age, gender and Child-Pugh score. All patients completed number connecting tests (NCTs), as well as a porto-systemic encephalopathy (PSE) syndrome test before and at 2 h after completion of the endoscopic procedure. Time needed to fulfill the tests was documented. Baseline results of the psychomotor test batteries were compared with the post-interventional evaluations. Data were also compared with the results of a healthy control group (n=20) that did not undergo endoscopic sedation. Recovery time and quality (score system) were evaluated.

RESULTS

The differences in the NCT times before and after sedation (median delta NCT, midazolam group, 11 s (95% CI, -1.2 to 16.1 s) versus the propofol group, -9.5 s (95% CI, -15.7 to -4.6 s), p=0.002) and in the PSE scores (median delta PSE, midazolam group, -1 (95% CI, -1.5 to 0.2) versus the propofol group, 1 (95% CI, 0.5 to 1.5), p=0.0009) differed significantly between the two groups. In addition, the recovery time and quality in patients receiving propofol were significantly improved compared with in the midazolam group (7.8+/-2.9 min versus 18.4+/-6.7 min, 6.1+/-1.1 versus 8.2+/-1.3, both p<0.001).

CONCLUSIONS

The study demonstrates that propofol sedation for upper GI endoscopy does not cause acute deterioration of minimal hepatic encephalopathy and is associated with improved recovery in patients with liver cirrhosis. Propofol should be recommended for these patients as an alternative to midazolam.

Deep sedation with propofol does not precipitate hepatic encephalopathy during elective upper endoscopy

BACKGROUND

The risk of hepatic encephalopathy (HE) precipitated by propofol has not been established.

OBJECTIVE

To know whether the use of propofol for endoscopy in patients with cirrhosis induces minimal or overt HE.

DESIGN

A cohort study.

SETTING

A tertiary-referral university hospital endoscopy unit.

PATIENTS

Patients with cirrhosis who received an endoscopy with propofol sedation. We excluded patients with clinical HE. A group of patients without liver disease was included to compare the incidence of adverse effects.

INTERVENTIONS

Minimal HE (MHE) was diagnosed by using the psychometric hepatic encephalopathy score (PHES) battery of psychometric tests. Cognitive status before and 1 hour after the endoscopy was evaluated by measuring the critical flicker frequency (CFF).

MAIN OUTCOME MEASUREMENTS

Overt and minimal HE.

RESULTS

Twenty patients with cirrhosis and 20 patients without cirrhosis were included. There were no differences between groups in the incidence of adverse effects. Thirteen patients (65%) had MHE before the endoscopy. No patient developed overt HE after sedation. We did not observe differences in CFF before and after sedation in patients without MHE: median (25th-75th percentile), 40.8 Hz (37.1-46.0 Hz) versus 41.1 Hz (36.0-44.3 Hz), P = .8). None of the patients who were without MHE showed a decrease in the CFF under the cutoff of 39 Hz after sedation. There were not significant changes in CFF before and after propofol sedation in patients previously diagnosed of MHE: median (25th-75th percentile), 40.6 Hz (36.8-49.1 Hz) versus 42.7 Hz (36.8-52.4 Hz), P = .08.

LIMITATION

A small number of patients were included in the study.

CONCLUSIONS

The use of propofol in the sedation of patients with cirrhosis during endoscopic procedures does not precipitate minimal or overt HE.

Reduced duodenal cytochrome P450 3A protein expression and catalytic activity in patients with cirrhosis

The small intestine and liver express high levels of cytochrome P450 3A (CYP3A), an enzyme subfamily that contributes significantly to drug metabolism. In patients with cirrhosis, reduced metabolism of drugs is typically attributed to decreased liver function, but it is unclear whether drug metabolism in the intestine is also compromised. In this study, we compared CYP3A protein expression and in vitro midazolam hydroxylation in duodenal mucosal biopsies from subjects with normal liver function (controls; n = 20) and subjects with various levels of severity of cirrhosis (n = 23). In samples from subjects with cirrhosis, duodenal CYP3A expression and total midazolam hydroxylation were lower by 47 and 34%, respectively, as compared with samples from controls. Greater decreases in CYP3A expression were seen in subjects with more severe cirrhosis. Therefore, patients with advanced cirrhosis may have greater drug exposure following oral dosing as a result of both impaired liver function and decreased intestinal CYP3A expression and activity.

Irreversible CYP3A inhibition accompanied by plasma protein-binding displacement: a comparative analysis in subjects with normal and impaired liver function

In this study, quinine was used as a probe substrate and erythromycin as a prototypical irreversible inhibitor of CYP3A to ascertain whether, like reversible CYP inhibition, the magnitude of irreversible inhibition is also strictly dependent on the status of liver function. The effect of erythromycin on oral quinine disposition was studied in 10 healthy subjects and in 20 patients with cirrhosis of the liver who had varying degrees of liver dysfunction. This effect was shown to be the result of two types of interaction: (i) irreversible inhibition of CYP3A-mediated quinine metabolism, the extent of which proved to be independent of liver function, and (ii) displacement of quinine from plasma protein-binding sites, the magnitude of the displacement increasing dramatically as liver function worsened. Such an interaction causes limited increases in the total concentration of the displaced drug but disproportionate increases in its free concentration; the latter increases are magnified by liver dysfunction, thereby requiring that the monitoring of free drug concentrations be made mandatory.

Pharmacokinetics and dosage adjustment in patients with hepatic dysfunction

The liver plays a central role in the pharmacokinetics of the majority of drugs. Liver dysfunction may not only reduce the blood/plasma clearance of drugs eliminated by hepatic metabolism or biliary excretion, it can also affect plasma protein binding, which in turn could influence the processes of distribution and elimination. Portal-systemic shunting, which is common in advanced liver cirrhosis, may substantially decrease the presystemic elimination (i.e., first-pass effect) of high extraction drugs following their oral administration, thus leading to a significant increase in the extent of absorption. Chronic liver diseases are associated with variable and non-uniform reductions in drug-metabolizing activities. For example, the activity of the various CYP450 enzymes seems to be differentially affected in patients with cirrhosis. Glucuronidation is often considered to be affected to a lesser extent than CYP450-mediated reactions in mild to moderate cirrhosis but can also be substantially impaired in patients with advanced cirrhosis. Patients with advanced cirrhosis often have impaired renal function and dose adjustment may, therefore, also be necessary for drugs eliminated by renal exctretion. In addition, patients with liver cirrhosis are more sensitive to the central adverse effects of opioid analgesics and the renal adverse effects of NSAIDs. In contrast, a decreased therapeutic effect has been noted in cirrhotic patients with beta-adrenoceptor antagonists and certain diuretics. Unfortunately, there is no simple endogenous marker to predict hepatic function with respect to the elimination capacity of specific drugs. Several quantitative liver tests that measure the elimination of marker substrates such as galactose, sorbitol, antipyrine, caffeine, erythromycin, and midazolam, have been developed and evaluated, but no single test has gained widespread clinical use to adjust dosage regimens for drugs in patients with hepatic dysfunction. The semi-quantitative Child-Pugh score is frequently used to assess the severity of liver function impairment, but only offers the clinician rough guidance for dosage adjustment because it lacks the sensitivity to quantitate the specific ability of the liver to metabolize individual drugs. The recommendations of the Food and Drug Administration (FDA) and the European Medicines Evaluation Agency (EMEA) to study the effect of liver disease on the pharmacokinetics of drugs under development is clearly aimed at generating, if possible, specific dosage recommendations for patients with hepatic dysfunction. However, the limitations of the Child-Pugh score are acknowledged, and further research is needed to develop more sensitive liver function tests to guide drug dosage adjustment in patients with hepatic dysfunction.

Pharmacokinetics and dosage adjustment in patients with hepatic dysfunction

The liver plays a central role in the pharmacokinetics of the majority of drugs. Liver dysfunction may not only reduce the blood/plasma clearance of drugs eliminated by hepatic metabolism or biliary excretion, it can also affect plasma protein binding, which in turn could influence the processes of distribution and elimination. Portal-systemic shunting, which is common in advanced liver cirrhosis, may substantially decrease the presystemic elimination (i.e., first-pass effect) of high extraction drugs following their oral administration, thus leading to a significant increase in the extent of absorption. Chronic liver diseases are associated with variable and non-uniform reductions in drug-metabolizing activities. For example, the activity of the various CYP450 enzymes seems to be differentially affected in patients with cirrhosis. Glucuronidation is often considered to be affected to a lesser extent than CYP450-mediated reactions in mild to moderate cirrhosis but can also be substantially impaired in patients with advanced cirrhosis. Patients with advanced cirrhosis often have impaired renal function and dose adjustment may, therefore, also be necessary for drugs eliminated by renal exctretion. In addition, patients with liver cirrhosis are more sensitive to the central adverse effects of opioid analgesics and the renal adverse effects of NSAIDs. In contrast, a decreased therapeutic effect has been noted in cirrhotic patients with beta-adrenoceptor antagonists and certain diuretics. Unfortunately, there is no simple endogenous marker to predict hepatic function with respect to the elimination capacity of specific drugs. Several quantitative liver tests that measure the elimination of marker substrates such as galactose, sorbitol, antipyrine, caffeine, erythromycin, and midazolam, have been developed and evaluated, but no single test has gained widespread clinical use to adjust dosage regimens for drugs in patients with hepatic dysfunction. The semi-quantitative Child-Pugh score is frequently used to assess the severity of liver function impairment, but only offers the clinician rough guidance for dosage adjustment because it lacks the sensitivity to quantitate the specific ability of the liver to metabolize individual drugs. The recommendations of the Food and Drug Administration (FDA) and the European Medicines Evaluation Agency (EMEA) to study the effect of liver disease on the pharmacokinetics of drugs under development is clearly aimed at generating, if possible, specific dosage recommendations for patients with hepatic dysfunction. However, the limitations of the Child-Pugh score are acknowledged, and further research is needed to develop more sensitive liver function tests to guide drug dosage adjustment in patients with hepatic dysfunction.

The budget impact of endoscopic screening for esophageal varices in cirrhosis

BACKGROUND

The cost-effectiveness of screening for esophageal varices in cirrhosis remains uncertain. Previous analyses found that screening with upper endoscopy (EGD) may not be cost effective versus empiric beta-blocker (BB) therapy. However, these models were conducted before advances in variceal screening, including capsule endoscopy (CE), and they did not measure the budget impact (vs cost-effectiveness) of variceal screening.

OBJECTIVE

To compare the managed care budget impact of variceal screening strategies.

DESIGN

Budget impact model.

SETTING

Hypothetical managed care organization with 1 million covered lives.

PATIENTS

Patients with compensated cirrhosis.

INTERVENTIONS

Compared 5 strategies: (1) empiric BB, (2) screening EGD followed by BB if varices present (EGD --> BB), (3) EGD followed by endoscopic band ligation if varices present (EGD --> EBL), (4) CE followed by BB if varices present (CE --> BB), and (5) CE followed by EBL if varices present (CE --> EBL).

MAIN OUTCOME MEASUREMENT

Per-member per-month cost.

RESULTS

BB was the least expensive, and CE --> EBL was the most expensive. Substituting CE --> BB in lieu of BB cost each member an additional $0.20 per month to subsidize. Compared with CE --> BB, both EGD-based strategies were more expensive. However, CE was not viable in managed care organizations capable of reducing the cost of endoscopy below $410, unless the cost of CE was reduced in lockstep.

LIMITATIONS

Data on CE remain limited.

CONCLUSIONS

Screening for varices may have an acceptable budget impact but is highly sensitive to local costs of EGD and CE. In managed care organizations willing to subsidize EBL for variceal prophylaxis, it is inefficient to screen with CE compared with EGD.

Alfentanil-induced miosis as a surrogate measure of alfentanil pharmacokinetics in patients with mild and moderate liver cirrhosis

OBJECTIVES

(i) To evaluate the pupillary response to alfentanil as a surrogate measure of alfentanil pharmacokinetics in cirrhotic patients and to compare the data observed in cirrhotic patients with those found in healthy volunteers (historical control group); and (ii) to compare this test with other liver function tests in cirrhotic patients.

METHODS

Six patients with mild cirrhosis (Child-Pugh grade A) and six patients with moderate cirrhosis (Child-Pugh grade B) were studied after a single 15 microg/kg bolus of alfentanil. Alfentanil plasma concentrations were measured by liquid chromatography-tandem mass spectrometry, and pupillary responses were measured with a Pupilscan II pupillometer. Alfentanil pharmacokinetics (plasma concentration, area under the plasma concentration-time curve from time zero to infinity [AUC(infinity(p))] and from time zero to 2 hours [AUC(2(p))], apparent volume of distribution at steady state, clearance and terminal elimination half-life [t((1/2)(p))]) and miosis pseudo-kinetic parameters [AUC(infinity)((miosis)), AUC(2)((miosis)), t((1/2))((miosis))] were determined using a noncompartmental analysis method. In six patients (three Child-Pugh grade A and three Child-Pugh grade B), antipyrine (measure of liver intrinsic activity) and D-sorbitol (measure of liver blood flow) tests were performed.

RESULTS

A significant correlation was found between the alfentanil AUC(infinity(p)) and AUC(infinity)((miosis)) (r = 0.6, p < 0.05) in cirrhotic patients. This correlation was even more significant if AUC determinations were limited to the first 2 hours after alfentanil administration (r = 0.9, p < 0.01). Statistically significant differences in pharmacokinetics and miosis pseudo-kinetic parameters were observed between cirrhotic patients and healthy volunteers from our previous experiment (historical control group). The correlations were significant between alfentanil clearance and antipyrine clearance (n = 6, r = 0.9, p < 0.05), alfentanil clearance and steady-state hepatic blood clearance [CL(H(b))] measured by the D-sorbitol test (n = 6, r = 0.9, p < 0.05).

CONCLUSION

Alfentanil pharmacokinetic parameters were correlated with miosis pseudo-kinetic parameters in cirrhotic patients. There was a significant decrease in pharmacokinetics and miosis pseudo-kinetics in cirrhotic patients compared with volunteers from the historical control group. Alfentanil-induced miosis has the advantage of being noninvasive and can be limited to miosis measurements during the first 2 hours after alfentanil administration in cirrhotic patients. We thus propose to substitute the AUC(2(miosis)) for alfentanil pharmacokinetics in cirrhosis.

Dose adjustment in patients with liver disease

Unfortunately, there is no endogenous marker for hepatic clearance that can be used as a guide for drug dosing. In order to predict the kinetic behaviour of drugs in cirrhotic patients, agents can be grouped according to their extent of hepatic extraction. For drugs with a high hepatic extraction (low bioavailability in healthy subjects), bioavailability increases and hepatic clearance decreases in cirrhotic patients. If such drugs are administered orally to cirrhotic patients, their initial dose has to be reduced according to hepatic extraction. Furthermore, their maintenance dose has to be adapted irrespective of the route of administration, if possible, according to kinetic studies in cirrhotic patients. For drugs with a low hepatic extraction, bioavailability is not affected by liver disease, but hepatic clearance may be affected. For such drugs, only the maintenance dose has to be reduced, according to the estimated decrease in hepatic drug metabolism. For drugs with an intermediate hepatic extraction, initial oral doses should be chosen in the low range of normal in cirrhotic patients and maintenance doses should be reduced as for high extraction drugs. In cholestatic patients, the clearance of drugs with predominant biliary elimination may be impaired. Guidelines for dose reduction in cholestasis exist for many antineoplastic drugs, but are mostly lacking for other drugs with biliary elimination. Dose adaptation of such drugs in cholestatic patients is, therefore, difficult and has to be performed according to pharmacological effect and/or toxicity. Importantly, the dose of drugs with predominant renal elimination may also have to be adapted in patients with liver disease. Cirrhotic patients often have impaired renal function, despite a normal serum creatinine level. In cirrhotic patients, creatinine clearance should, therefore, be measured or estimated to gain a guideline for the dosing of drugs with predominant renal elimination. Since the creatinine clearance tends to overestimate glomerular filtration in cirrhotic patients, the dose of a given drug may still be too high after adaptation to creatinine clearance. Therefore, the clinical monitoring of pharmacological effects and toxicity of such drugs is important. Besides the mentioned kinetic changes, the dynamics of some drugs is also altered in cirrhotic patients. Examples include opiates, benzodiazepines, NSAIDs and diuretics. Such drugs may exhibit unusual adverse effects that clinicians should be aware of for their safe use. However, it is important to realise that the recommendations for dose adaptation remain general and cannot replace accurate clinical monitoring of patients with liver disease treated with critical drugs.

An overview of psychiatric issues in liver disease for the consultation-liaison psychiatrist

Liver disease is a common cause of morbidity and mortality in the United States and elsewhere. Arising from infectious, hereditary, or toxin-induced sources, the detection of liver disease often requires a high index of suspicion. Clinical presentations are highly variable and are often accompanied by neuropsychiatric symptoms. This fact, along with an increased incidence of liver disease among patients with primary psychiatric disorders and the presence of varied drug use, complicates the tasks of providing care to patients with liver disease. To assist the consultation-liaison psychiatrist, the authors present the first of a two-part series focused on psychiatric issues in liver disease.