Effects of ethanol on drug and metabolite pharmacokinetics

Therapeutic Effects of Myriocin in Experimental Alcohol-Related Neurobehavioral Dysfunction and Frontal Lobe White Matter Biochemical Pathology

Background & Objective

Chronic excessive alcohol consumption causes white matter degeneration with myelin loss and impaired neuronal conductivity. Subsequent rarefaction of myelin accounts for the sustained deficits in cognition, learning, and memory. Correspondingly, chronic heavy or repeated binge alcohol exposures in humans and experimental models alter myelin lipid composition leading to build-up of ceramides which can be neurotoxic and broadly inhibitory to brain functions.

Methods

This study examined the effects of chronic + binge alcohol exposures (8 weeks) and intervention with myriocin, a ceramide inhibitor, on neurobehavioral functions (Open Field, Novel Object Recognition, and Morris Water Maze tests) and frontal lobe white matter myelin lipid biochemical pathology in an adult Long-Evans rat model.

Results

The ethanol-exposed group had significant deficits in executive functions with increased indices of anxiety and impairments in spatial learning acquisition. Myriocin partially remediated these effects of ethanol while not impacting behavior in the control group. Ethanol-fed rats had significantly smaller brains with broadly reduced expression of sulfatides and reduced expression of two of the three sphingomyelins detected in frontal white matter. Myriocin partially resolved these effects corresponding with improvements in neurobehavioral function.

Conclusion

Therapeutic strategies that support cerebral white matter myelin expression of sulfatide and sphingomyelin may help remediate cognitive-behavioral dysfunction following chronic heavy alcohol consumption in humans.

Alcohol-medication interactions: A systematic review and meta-analysis of placebo-controlled trials

Alcohol and other xenobiotics may limit the therapeutic effects of medications. We aimed at investigating alcohol-medication interactions (AMI) after the exclusion of confounding effects related to other xenobiotics. We performed a systematic review and meta-analysis of controlled studies comparing the effects induced by alcohol versus placebo on pharmacodynamic and/or pharmacokinetic parameters of approved medications. Certainty in the evidence of AMI was assessed when at least 3 independent studies and at least 200 participants were available. We included 107 articles (3097 participants): for diazepam, cannabis, opioids, and methylphenidate, we found significant AMI and enough data to assign the certainty of evidence. Alcohol consumption significantly increases the peak plasma concentration of diazepam (low certainty; almost 290 participants), cannabis (high certainty; almost 650 participants), opioids (low certainty; 560 participants), and methylphenidate (moderate certainty; 290 participants). For most medications, we found some AMI but not enough data to assign them the certainty grades; for some medications, we found no differences between alcohol and placebo in any outcomes evaluated. Our results add further evidence for interactions between alcohol and certain medications after the exclusion of confounding effects related to other xenobiotics. Physicians should advise patients who use these specific medications to avoid alcohol consumption. Further studies with appropriate control groups, enough female participants to investigate sex differences, and elderly population are needed to expand our knowledge in this field. Short phrases suitable for indexing terms.

Influence of Ethanol on Darunavir Hepatic Clearance and Intracellular PK/PD in HIV-Infected Monocytes, and CYP3A4-Darunavir Interactions Using Inhibition and in Silico Binding Studies

PURPOSE

Although the prevalence of alcohol consumption is higher in HIV+ people than general public, limited information is available on how alcohol affects the metabolism and bioavailability of darunavir (DRV).

METHODS

DRV was quantified by using LC-MS/MS method. All in vitro experiments were performed using human liver microsomes and HIV-infected monocytic cells. CYP3A4 and DRV/Ritonavir (RTV) docking was performed using GOLD suite 5.8.

RESULTS

Ethanol (20 mM) significantly decreased apparent half-life and increased degradation rate constant of RTV-boosted DRV but not for DRV alone. Similarly, ethanol exposure increased hepatic intrinsic clearance for RTV-boosted DRV with no significant influence on DRV alone. Ethanol showed a limited influence on intracellular total DRV exposure in the presence of RTV without altering maximum concentration (C_max) values in HIV-infected monocytic cells. Ethanol alone elevated HIV replication but this effect was nullified with the addition of DRV or DRV + RTV. Additionally, inhibitory potency of DRV was significantly reduced in the presence of ethanol. Our docking results projected that ethanol increases the average distance between DRV and CYP3A4 heme, and alter the orientation of DRV-CYP3A4 binding.

CONCLUSIONS

Collectively these findings suggest that DRV metabolism is primarily influenced by ethanol in the liver, but has minor effect in HIV-residing monocytes.

Influence of ethanol on cannabinoid pharmacokinetic parameters in chronic users

Cannabis is not only the most widely used illicit drug worldwide but is also regularly consumed along with ethanol. In previous studies, it was assumed that cannabis users develop cross-tolerance to ethanol effects. The present study was designed to compare the effects of ethanol in comparison to and in combination with a cannabis joint and investigate changes in pharmacokinetics. In this study, 19 heavy cannabis users participated and received three alcohol dosing conditions that were calculated to achieve steady blood alcohol concentrations (BAC) of about 0, 0.5 and 0.7 g/l during a 5-h time window. Subjects smoked a Δ(9)-tetrahydrocannabinol (THC) cigarette (400 μg/kg) 3 h post-onset of alcohol dosing. Blood samples were taken between 0 and 4 h after smoking. During the first hour, samples were collected every 15 min and every 30 min thereafter. Mean steady-state BACs reached 0, 0.36 and 0.5 g/l. The apparent elimination half-life of THC was slightly prolonged (1.59 vs. 1.93 h, p < 0.05) and the concentration 1 h after smoking was slightly lower (24 vs. 17 ng/ml, p < 0.05) with the higher ethanol dose. The prolonged THC elimination might be explained by a small ethanol-mediated change in distribution to and from deep compartments. Concentrations and pharmacokinetics of 11-hydroxy-THC and 11-nor-9-carboxy-THC (THCA) were not significantly influenced by ethanol. However, THCA concentrations appeared lower in both ethanol conditions, which might also be attributable to changes in distribution. Though not significant in the present study, this might be relevant in the interpretation of cannabinoid concentrations in blood.

Effects of ethanol and phenobarbital on hemoglobin adducts formation in rats exposed to benzidine and Direct Black 38

The objective of this study was to evaluate the effects of pretreatment of ethanol (EtOH) and phenobarbital (PB), which are known to affect the metabolism of xenobiotics, in the formation of hemoglobin adducts in rats administered with benzidine (BZ) and Direct Black 38 (DB38). The experimental rats were divided into BZ and DB38 groups; each group was subdivided into control, EtOH, and PB groups. Blood samples were separated into hemoglobin and plasma immediately after obtaining and basic hydrolysis was done to convert the adducts into aromatic amines. Hydrolyzed BZ, monoacetylbenzidine (MABZ), and 4-aminobiphenyl (4ABP) were separated by reversed-phase liquid chromatography without derivatization. Then, quantitative analyses were performed using a high performance liquid chromatograph equipped with an electrochemical detector. The amount of metabolites was expressed in the hemoglobin binding index (HBI). As a result, the formations of hemoglobin in BZ-, MABZ-, and 4ABP-HBI of BZ-EtOH and BZ-PB groups were increased compared with those of BZ-control group. In DB38 group, all of HBIs except for BZ-HBI were increased more than those of DB38-control group regardless of the pretreatment. These results are attributable to the fact that EtOH and PB induced N-hydroxylation is related to the formation of hemoglobin adducts. They indicate that EtOH not only increases the adduct formation by inducing N-hydroxylation but also induces N-acetylation. PB induced N-hydroxylation and increased the adduct formation in BZ group, but decreased the adduct formation in DB38 group due to decreasing azo reduction. These results suggest that the effects of EtOH or PB should be considered in biochemical monitoring of BZ and DB38 for the assessment of intermittent exposure to BZ and DB38.

Pharmacokinetics and metabolism of a selective androgen receptor modulator in rats: implication of molecular properties and intensive metabolic profile to investigate ideal pharmacokinetic characteristics of a propanamide in preclinical study

S-1 [3-(4-fluorophenoxy)-2-hydroxy-2-methyl-N-[4-nitro-3-(trifluoromethyl)phenyl]-propanamide] is one member of a series of potent selective androgen receptor modulators (SARMs) that are being explored and developed for androgen-dependent diseases. Recent studies showed that S-1 holds great promise as a novel therapeutic agent for benign hyperplasia [W. Gao, J. D. Kearbey, V. A. Nair, K. Chung, A. F. Parlow, D. D. Miller, and J. T. Dalton (2004) Endocrinology 145:5420-5428]. We examined the pharmacokinetics and metabolism of S-1 in rats as a component of our preclinical development of this compound and continued interest in structure-activation relationships for SARM action. Forty male Sprague-Dawley rats were randomly assigned to treatment groups and received either an i.v. or a p.o. dose of S-1 at a dose level of 0.1, 1, 10, or 30 mg/kg. S-1 demonstrated a low clearance (range, 3.6-5.2 ml/min/kg), a moderate volume of distribution (range, 1460-1560 ml/kg), and a terminal half-life ranging from 3.6 to 5.2 h after i.v. doses. The oral bioavailability of S-1 ranged from 55% to 60%. Forty phase I and phase II metabolites of S-1 were identified in the urine and feces of male Sprague-Dawley rats dosed at 50 mg/kg via the i.v. route. The two major urinary metabolites of S-1 were a carboxylic acid and a sulfate-conjugate of 4-nitro-3-trifluoromethylphenylamine. Phase I metabolites arising from A-ring nitro reduction to an aromatic amine and B-ring hydroxylation were also identified in the urinary and fecal samples of rats. Furthermore, a variety of phase II metabolites through sulfation, glucuronidation, and methylation were also found. These studies demonstrate that S-1 is rapidly absorbed, slowly cleared, moderately distributed, and extensively metabolized in rats.

Interpretation of analytical toxicology results in life and at postmortem

Interpretation of analytical toxicology results from live patients is sometimes difficult. Possible factors may be related to: (i) the nature of the poison(s) present; (ii) sample collection, transport and storage; (iii) the analytical methodology used; (iv) the circumstances of exposure; (v) mechanical factors such as trauma or inhalation of stomach contents; and (vi) pharmacological factors such as tolerance or synergy. In some circumstances, detection of a drug or other poison may suffice to prove exposure. At the other extreme, the interpretation of individual measurements may be simplified by regulation. Examples here include whole blood alcohol (ethanol) in regard to driving a motor vehicle and blood lead assays performed to assess occupational exposure. With pharmaceuticals, the plasma or serum concentrations of drugs and metabolites attained during treatment often provide a basis for the interpretation of quantitative measurements. With illicit drugs, comparative information from casework may be all that is available. Postmortem toxicology is an especially complex area since changes in the composition of fluids such as blood depending on the site of collection from the body and the time elapsed since death, amongst other factors, may influence the result obtained. This review presents information to assist in the interpretation of analytical results, especially regarding postmortem toxicology. Collection and analysis of not only peripheral blood, but also other fluids/tissues is usually important in postmortem work. Alcohol, for example, can be either lost from, or produced in, blood especially if there has been significant trauma, hence measurements in urine or vitreous humour are needed to confirm the reliability of a blood result. Measurement of metabolites may also be valuable in individual cases.

Dietary resveratrol does not affect intestinal tumorigenesis in Apc(Min/+) mice

To determine its effect on intestinal tumorigenesis and the protumorigenic COX pathway in Apc(Min/+) mice, resveratrol was administered as a powdered admixture in the diet at 0, 4, 20, or 90 mg/kg body weight for 7 wk. In two separate experiments, resveratrol did not affect intestinal tumor load. It was stable in the diet under experimental conditions, circulated in the plasma as the glucuronide-conjugated form and reached the tumors as evidenced by significant decreases in PGE2 levels. However, immunohistochemical staining of intestinal tumors revealed no changes in COX-2 expression. This study demonstrates that resveratrol consumed ad libitum in the diet, does not modify tumorigenesis in Apc(Min/+) mice.

Toxicological interactions involving psychiatric drugs and alcohol: an update

This review focuses on the toxicological interactions between alcohol (ethanol) and psychiatric drugs (antidepressants and antipsychotics), including those leading to fatal poisoning. Acute or chronic ingestion of alcohol when combined with psychiatric drugs may lead to several clinically significant toxicological interactions. The metabolism of these drugs is generally but not always delayed by acute alcohol ingestion. Drugs undergoing metabolism may also show increased metabolic clearance with chronic alcohol ingestion. Therefore, the net effect may be influenced by internal (e.g. disease, age, gender), external (e.g. environment, diet) and pharmacokinetic (e.g. dose, timing of ingestion, gastrointestinal absorption, distribution and elimination) factors. Cases of fatal poisoning involving coadministration of psychiatric drugs, alcohol and other drugs prompted this review.

Toxicological interactions between alcohol and benzodiazepines

BACKGROUND

We review recentfindings on the toxicological interactions between alcohol (ethanol) and benzodiazepines, and the combined use of benzodiazepines and alcohol in fatal poisoning. Acute ingestion of alcohol combined with benzodiazepines is responsible for several toxicological interactions that can have significant clinical implications. In general, metabolism of these drugs is delayed when combined with acute alcohol ingestion although some reports suggest otherwise. Alternately, the drugs metabolized during chronic alcohol ingestion have an increased clearance. The net effect may also be influenced by internal (e.g., disease, age) and external (e.g., environment, diet) factors. Fatal poisoning involving coadministration of alcohol and benzodiazepine, especially triazolam, continues to be a serious problem.

When midazolam fails

Significant distress is experienced by patients, families, and caregivers when a symptom or disorder, such as an agitated delirium, becomes an intractable, or a catastrophic event, such as irreversible stridor. When palliative sedation is indicated for these patients, midazolam is usually the preferred drug. In some cases, however, midazolam fails to provide adequate sedation. Two cases are presented to illustrate this phenomenon and explore the possible mechanisms underlying this lack of response. These mechanisms appear to be multifaceted. The heterogeneity of the GABA(A) receptor complex and the alterations that this complex can undergo functionally can explain, to some degree, the diversity of the physiological and pharmacological outcomes. Other factors responsible for the diversity in response may include concomitant medications, age, concurrent disease, overall health status, alcohol use, liver disease, renal disease, smoking and hormonal status. Evidence-based guidelines on alternative treatment options should midazolam fail are required. In the interim, a lower threshold for adding an alternative drug, such as phenobarbital, or substituting midazolam with another drug, such as propofol, should be considered in these circumstances.

Alcohol up-regulates UDP-glucuronosyltransferase mRNA expression in rat liver and in primary rat hepatocyte culture

The interactions between alcohol and cytochrome P-450 enzymes have been well investigated. However, the data regarding the effect of alcohol on the regulation of UDP-glucuronosyltranferase (UGT) activity are less clear. The aim of the present study was to determine the role of alcohol in the regulation of UGT mRNA expression by using whole animal and primary cultured hepatocytes. Chronic ethanol feeding of rats significantly increased the expression of liver UGT1A1 mRNA to 177% of control. The mRNA levels for UGT1A5, UGT2B1 and UGT2B3 were also enhanced, but did not reach statistical significance. In cultured hepatocytes, treatment with either ethanol or isopentanol significantly increased the expression of UGT1A1, UGT1A5, UGT2B1, and UGT2B3 mRNAs, but to different degrees. The induction of UGT1A1 and UGT2B1 mRNAs by ethanol or isopentanol was time-dependent and maximal changes occurred at 48 h. The expression of UGT1A6 mRNA was not significantly modified by either ethanol or isopentanol. In conclusion, ethanol and isopentanol have direct roles in the regulation of UGT.

Gender differences in depression and antidepressant pharmacokinetics and adverse events

OBJECTIVE

To review data generated by studies examining gender differences in the prevalence of depression, as well as in antidepressant pharmacokinetics, pharmacodynamics, and adverse events.

DATA SOURCES

Published articles and abstracts were identified through MEDLINE (January 1966-April 1999) using the following search terms: antidepressant, response, gender, pharmacokinetic, pharmacodynamic, female, side effect, and adverse events. All articles that assessed gender differences in antidepressant response, pharmacokinetics, and adverse events, as well as articles that evaluated postulated mechanisms for these differences, were reviewed. Additional articles were identified from bibliographies of retrieved articles.

STUDY SELECTION AND DATA EXTRACTION

All relevant abstracts, studies, and review articles were evaluated.

DATA SYNTHESIS

Gender differences in the prevalence of depression have been reported and may result from the interaction of several factors. Women have been shown to have a higher incidence of depression, which may be due to artifact, social, or biologic reasons. Studies suggest that the pharmacokinetic disposition of popular antidepressants varies between men and women, and women taking antidepressants may exhibit a different adverse event profile. Only one study specifically evaluated gender differences in antidepressant treatment response.

CONCLUSIONS

Further research elucidating gender differences in response to antidepressant treatment and on depression prevalence is needed. Some studies report that the pharmacokinetics of antidepressants may vary between men and women. Therefore, clinicians should be aware that potential differences in antidepressant pharmacokinetics may exist, and a dosage adjustment may be necessary for women to ensure a favorable drug response, compliance, and decreased incidence of adverse events.

Clinically significant pharmacokinetic drug interactions with benzodiazepines

The reports of interactions between benzodiazepines (BZPs) and other drugs (e.g., antidepressants, selective serotonin reuptake inhibitors, antiulcer drugs, antiepileptic drugs, macrolide antibiotics) during their combined use are reviewed. In general, metabolism of BZPs is delayed when combined with a number of other drugs but some reports have suggested otherwise. In recent years, the cytochrome P450 (P450 or CYP) isoenzyme that catalyses the metabolism of BZPs has also been identified. BZPs are mainly catalysed by CYP3A4. When published reports are studied, it appears necessary to be exceptionally careful about interactions mainly between BZPs and selective serotonin reuptake inhibitors, cimetidine, antiepileptic drugs, macrolide antibiotics and antimycotics. More information is necessary to identify individuals at greatest risk of drug interactions and adverse events.

Pharmacokinetic interactions between acute alcohol ingestion and single doses of benzodiazepines, and tricyclic and tetracyclic antidepressants -- an update

Recent reports of interactions between alcohol and benzodiazepines, tricyclic and tetracyclic antidepressants during their acute concomitant use are reviewed. Acute ingestion of alcohol (ethanol) with tranquilizers or hypnotics is responsible for several pharmacokinetic interactions that can have significant clinical implications. In general, metabolism of these drugs is delayed when combined with alcohol but some reports have suggested otherwise. The amount of alcohol consumed, the presence or absence of liver disease, and differences in the dosage and administration of these drugs may account for the observed discrepancies. In recent years, the cytochrome P450 (P450 or CYP) isoenzyme that catalyses the metabolism of these drugs has also been identified. However, since changes in the pharmacogenetic metabolism of benzodiazepines and tricyclic and tetracyclic antidepressants are mainly governed by CYP2C19 and CYP2D6, caution is needed when used together with alcohol.

A review of the effects of moderate alcohol intake on psychiatric and sleep disorders

In this chapter we discuss the effects of moderate ethanol consumption on the treatment of psychiatric and sleep disorders. A review of the literature on the interactions of ethanol with neurotransmitters and psychotropic medications suggests that although ethanol affects the clinical course of psychiatric and sleep disorders by different mechanisms, it does so principally through perturbations it causes in the balance of central nervous system neurotransmitter systems, which may modify the clinical course of primary psychiatric and sleep disorders and undermine the therapeutic response to psychotropic medications. Neurotransmitter responses may also be manifested clinically by rebound phenomena, akin to a subsyndromal withdrawal, which affect sleep and precipitate anxiety and mood symptoms. In addition, ethanol also modifies the clearance and disposition of a variety of psychotropic metabolites and interferes with their clinical effectiveness. We recommend that most psychiatric patients, and all patients with sleep disorders, should abstain from even moderate ethanol use, as this may adversely affect their clinical course and response to treatment.

Ethnicity and antipsychotic response

OBJECTIVE

To review the data generated by studies examining interethnic/racial differences in response to antipsychotics.

DATA SOURCES

A MEDLINE search (1966-1996) identified all articles examining differences in antipsychotic response among Caucasians, Asians, Hispanics, and African-Americans, as well as articles evaluating postulated mechanisms for these differences.

STUDY SELECTION

All abstracts, studies, and review articles were evaluated.

DATA SYNTHESIS

Ethnic/racial differences in response to antipsychotic medications have been reported and may be due to genetics, kinetic variations, dietary or environmental factors, or variations in the prescribing practices of clinicians. Studies suggest that Asians may respond to lower doses of antipsychotics due to pharmacokinetic and pharmacodynamic differences. Research relevant to African-Americans is limited, but some studies suggest that differences in this group may be due to clinician biases and prescribing practices, rather than to pharmacokinetic or pharmacodynamic variability.

CONCLUSIONS

Future research directed at validating the hypotheses that different ethnic/racial groups show variations in response to antipsychotics should focus on homogeneous ethnic groups, use recent advances in pharmacogenetic testing, and control for such variables as observer bias, gender, disease chronicity, dietary and environmental factors, and exposure to enzyme-inducing and -inhibiting agents. Clinicians should be aware that potential interethnic/racial differences in pharmacodynamics and pharmacokinetics may exist that can alter response to antipsychotics.

Pharmacokinetic interactions between alcohol and other drugs

The frequent use of alcohol (ethanol) together with prescription drugs gives any described pharmacokinetic interaction significant clinical implications. The issue is both the effect of alcohol on the pharmacokinetics of various drugs and also the effect of those drugs on the pharmacokinetics of alcohol. This review discusses these pharmacokinetic interactions but also briefly describes some other effects of alcohol that are clinically relevant to drug prescribing. The use of several different study designs may be required before we can confidently state the presence or absence of any alcohol-drug interaction. Short term administration of alcohol in volunteers is the most common study design but studies of social drinking and prolonged moderate alcohol intake can be important in some situations. Community-based studies may illustrate the clinical relevance of any interaction. Alcohol can affect the pharmacokinetics of drugs by altering gastric emptying or liver metabolism (by inducing cytochrome P450 2E1). Drugs may affect the pharmacokinetics of alcohol by altering gastric emptying and inhibiting gastric alcohol dehydrogenase. The role of gastric alcohol dehydrogenase in the first-pass metabolism of alcohol is reviewed in this article and the arguments for and against any potential interaction between alcohol and H2 receptor antagonists are also discussed. The inhibition of the metabolism of acetaldehyde may cause disulfiram-like reactions. Pharmacodynamic interactions between alcohol and prescription drugs are common, particularly the additive sedative effects with benzodiazepines and also with some of the antihistamine drugs; other interactions may occur with tricyclic antidepressants. Alcohol intake may be a contributing factor to the disease state which is being treated and may complicate treatment because of various pathophysiological effects (e.g. impairment of gluconeogenesis and the risk of hypoglycaemia with oral hypoglycaemic agents). The combination of nonsteroidal anti-inflammatory drugs and alcohol intake increases the risk of gastrointestinal haemorrhage.

Role of CYP3A in ethanol-mediated increases in acetaminophen hepatotoxicity

CYP2E is considered the only form of cytochrome P450 responsible for ethanol-mediated increases in acetaminophen hepatotoxicity. However, in experimental systems used for investigating ethanol-mediated increases in acetaminophen hepatotoxicity, animals are withdrawn from ethanol for 16 to 24 hr before the administration of acetaminophen to ensure the clearance of ethanol from the circulation. In rats, CYP2E has been shown to decrease to control levels after this time period of withdrawal from ethanol. We have previously shown in cultured human and rat hepatocytes, and in intact rats, that ethanol induces CYP3A in addition to CYP2E. To determine if there might be a role for CYP3A in ethanol-mediated APAP hepatotoxicity in addition to the recognized role for CYP2E, we investigated the effect of triacetyloleandomycin (TAO) on acetaminophen hepatotoxicity in ethanol-pretreated rats, as well as the effect of 11 hr withdrawal from ethanol on hepatic levels of CYP3A and CYP2E. TAO was dissolved in saline instead of dimethylsulfoxide, the solvent most usually employed, since dimethylsulfoxide inhibits CYP2E. Rats were administered 6.3% ethanol as part of the Lieber-DeCarli diet for 7 days, followed by replacement of the liquid diet with water for 11 hr. This 11-hr withdrawal from ethanol resulted in a decrease in hepatic levels of ethanol-induced CYP2E; however, considerable induction was still evident. There was no significant decrease in CYP3A. TAO completely prevented the histologically observed liver damage from acetaminophen in ethanol-pretreated rats, but did not prevent the increase in serum levels of AST. In ethanol-pretreated rats, exposure to APAP in the absence of TAO was associated with a 75% decrease in CYP3A, compared to animals exposed to APAP in the presence of TAO. These results suggest that CYP3A may have been suicidally inactivated by acetaminophen in the absence of TAO. Our findings suggest that CYP3A has a major role in ethanol-mediated increases in acetaminophen hepatotoxicity.

Pharmacokinetic studies using microdialysis probes in subcutaneous tissue: effects of the co-administration of ethanol and acetaminophen

Loop geometry microdialysis probes with membrane lengths of 40-60 mm were used to monitor the effects of acute and chronic doses of ethanol on acetaminophen pharmacokinetics in awake, freely-moving rats. Microdialysis probes used in this configuration provide very high concentration recoveries and good precision at flow rates below 2 microliters min-1. The ability of microdialysis to monitor pharmacokinetics in subcutaneous tissue and blood vessels is compared. Dialysates acquired simultaneously from both blood vessels and subcutaneous tissue showed corresponding disposition for acetaminophen. Acute intraperitoneal doses of ethanol (1 ml kg-1) are shown to increase the relative bioavailability, measured as AUC, by 40%, elimination half-life by 24%, and changes in CL and Vd were also observed. Larger doses of ethanol, up to 2 ml kg-1, had a similar incremental effect on the pharmacokinetic parameters in some animals, but apparent decreased abdominal blood flow in others caused diminished absorption and drastically altered pharmacokinetic parameters. Chronic doses of ethanol (5% in drinking water for 14 days) caused an increase in bioavailability and other pharmacokinetic parameters, but changes were not as significant as following acute doses. Acute doses of ethanol (1 ml kg-1) were also observed to change the pharmacokinetics of acetaminophen at hepatotoxic levels of the drug. However, acute intraperitoneal doses of acetaminophen (10 mg kg-1) were observed not to have an effect on ethanol pharmacokinetics.

Mechanisms of ethanol-drug-nutrition interactions

Mechanisms of the toxicologic manifestations of ethanol abuse are reviewed. Hepatotoxicity of ethanol results from alcohol dehydrogenase-mediated excessive hepatic generation of nicotinamide adenine dinucleotide and acetaldehyde. It is now recognized that acetaldehyde is also produced by an accessory (but inducible) pathway, the microsomal ethanol-oxidizing system, which involves a specific cytochrome P450. It generates oxygen radicals and activates many xenobiotics to toxic metabolites, thereby explaining the increased vulnerability of heavy drinkers to industrial solvents, anesthetics, commonly used drugs, over-the-counter medications and carcinogens. The contribution of gastric alcohol dehydrogenase to the first pass metabolism of ethanol and alcohol-drug interactions is now recognized. Alcohol also alters the degradation of key nutrients, thereby promoting deficiencies as well as toxic interactions with vitamin A and beta-carotene. Conversely, nutritional deficits may affect the toxicity of ethanol and acetaldehyde, as illustrated by the depletion in glutathione, ameliorated by S-adenosyl-L-methionine. Other supernutrients include polyenylphosphatidylcholine, shown to correct the alcohol-induced hepatic phosphatidylcholine depletion and to prevent alcoholic cirrhosis in non-human primates. Thus, a better understanding of the pathology induced by ethanol has now generated improved prospects for therapy.

Metabolic interaction of ethanol and cyclohexanone in rabbits

The interaction of ethanol (EtOH) and cyclohexanone (CHN) metabolism was studied to demonstrate the influence of alcohol beverage in cyclohexanone poisoning. Rabbits were administered CHN and EtOH separately or together, and the plasma concentration of CHN and cyclohexanol (CHL), a metabolite of CHN, and blood concentrations of EtOH were measured at various times. When CHN alone was administered orally, the time to maximum plasma concentration (Tmax) of CHN was as short as 15 min, but that of CHL was 120 min. The short Tmax of CHN was considered to be due to the first-pass effect. The plasma concentration of CHL was much greater than that of CHN. On the other hand, when the same amount of molar CHL was administered in rabbits for sake of comparison, only small amounts of CHN were detected in plasma. The interconversion between CHN and CHL at the time of equilibration tended to shift predominantly toward the formation of CHL, whose plasma concentration ratio was about 1:6 to 1:8. The coadministration of EtOH decreased the plasma concentration of CHN and increased that of CHL more than the administration of CHN alone. The blood concentration of EtOH was also decreased with the coadministration of CHN. The coadministration of EtOH with CHN demonstrated an acceleration in the metabolism of both CHN and EtOH, which may be due to an increase in the concentrations of the alcohol dehydrogenase-NADH and -NAD complexes.

Alcohol intoxication does not change [11C]cocaine pharmacokinetics in human brain and heart

There is increasing evidence that the combined use of cocaine and alcohol produces enhanced behavioral and toxic effects. We have used PET and tracer doses of [11C]cocaine in 7 normal human volunteers to assess if the distribution and clearance of cocaine are altered by alcohol intoxication. Each subject received 2 PET studies with [11C]cocaine (3-11 micrograms), one before and one during alcohol intoxication (1 g/kg). Regions of interest included the brain (n = 3) and heart (n = 4). Arterial plasma was assayed for unchanged cocaine and for labeled cocaethylene, a metabolite of cocaine found in individuals using cocaine and alcohol in combination (Hearn et al., 1991a). Alcohol intoxication did not change uptake and clearance or the steady-state distribution volume of [11C] cocaine in brain (striatum, thalamus, and cerebellum) or in heart. Moreover, labeled cocaethylene was not detected in the 10 minute plasma sample. These results suggest that the acute enhancement of behavior and toxicity associated with the combined use of cocaine and alcohol is not due to an alteration in cocaine's organ distribution or to cocaethylene formation but may be related to an additive effect resulting from the direct actions of each of these drugs.

Effect of an acute dose of alcohol on the pharmacokinetics of oral nifedipine in humans

Pharmacokinetic and pharmacodynamic interactions of alcohol and nifedipine were assessed in 10 healthy human volunteers. Doses of 20 mg (2 x 10-mg capsules) of nifedipine were administered with either 150 ml of orange juice or 75 ml of alcohol (94%) in 75 ml of orange juice according to a crossover randomized design. Plasma nifedipine levels were monitored for 16 hr after each dosing, along with pulse rate and blood pressure. The relative bioavailability of nifedipine, measured as AUC, was increased by 54% (533 vs 346 ng.hr/ml) after the dose of alcohol (P less than 0.0002). However, there were no significant differences between treatments in Cmax, tmax, or t1/2. Although there was no difference in the systolic and diastolic blood pressure and pulse rate between the two treatment groups, the time to reach peak heart rate was significantly faster in the group treated with alcohol (1.4 vs 2.2 hr). This study shows that ethanol increases the bioavailability of nifedipine and decreases the time for onset of increased heart rate.

Substance abuse and schizophrenia: impediments to optimal care

With lifetime prevalence estimates of substance abuse among schizophrenics as high as 47.01%, there is an increasing awareness of the importance of this dual diagnosis and the global deficiencies in our knowledge about this comorbid condition. Patients with substance abuse disorders and schizophrenia are problematic from a clinical, economic, and health care systems perspective. The lack of systematic research into phenomenology, etiology, and treatment approaches (both psychotherapeutic and psychopharmacologic) has hindered the development of an adequate strategy to care for the needs of these patients. Thus, these patients place a significant burden on the mental health delivery system through chronic disability, social dysfunction, frequent rehospitalizations, and poor overall treatment compliance. The authors critically review the contemporary literature relevant to concurrent substance abuse and schizophrenia, highlight major deficiencies in our knowledge, and call for research to reduce the individual, economic, and social costs of this condition.

Effects of ethanol on the pharmacokinetics of cephalexin and cefadroxil in the rat

Data are presented on the effect of ethanol on the intestinal absorption and excretion in rats of two beta-lactam antibiotics, cephalexin (CFX) and cefadroxil (CFD). A recirculating perfusion technique within an antibiotic concentration range of 0.5 to 50 mM was used. Ethanol was administered either in an acute form into the intestine or in a chronic form as a 15% drinking solution for 2 months. The results are normalized in relation to the metabolic body weight, intestinal length, and osmotic conditions. Acute ethanol treatment decreases the antibiotic absorption; biliary excretion of CFD is increased, while urinary excretion of CFX is lowered. Chronic treatment shows slight negative effects on the absorption of CFX and CFD. Results are interpreted on the basis of the effect of ethanol on biological membranes. Enhanced urinary excretion after acute ethanol treatment, as well as differences between transport mechanisms, are invoked to explain these effects.

Chronic ethanol consumption causes increased glucuronidation of morphine in rabbits

1. Male rabbits were given an i.p. injection of 15 mg/kg morphine and plasma concentrations of morphine and morphine-3-glucuronide (M3G) were simultaneously quantified by h.p.l.c. After 14 days of 10% ethanol in the rabbits' drinking water, a second injection of morphine was administered and plasma concentrations were determined again. 2. Morphine plasma clearance increased significantly by 42% after ethanol treatment. The area under the plasma concentration time curve (AUC) for morphine decreased by 23% while the AUC for the glucuronide increased by 22%. 3. The ratio of the AUCs (glucruonide/morphine) increased by 72%. These results demonstrate that chronic ethanol treatment of rabbits results in increased clearance of morphine after an i.p. dose. The increase in clearance is most likely due to induction of UDP-glucuronosyltransferase isozymes by ethanol.

The interaction of alcohol and beta-blockers in arterial hypertension

The acute effects of consuming alcohol after a single oral dose of 200 mg of metoprolol or placebo were examined in eight healthy men in a randomized, controlled study. Alcohol, in a dose of 0.75 g/kg body weight, did not abolish the antihypertensive effect of metoprolol upon supine systolic blood pressure. The interaction of alcohol with antihypertensive drugs requires further investigation as hypertensive patients who consume alcohol regularly are known to have less adequate blood pressure control.

Clomipramine metabolism. Model-based analysis of variability factors from drug monitoring data

A steady-state model is here developed as a framework for the analysis of blood concentrations of clomipramine, obtained during routine drug monitoring. A model is proposed to account for its major metabolic pathways, hydroxylation and demethylation, including first-pass effect. Impaired hydroxylation capacity is shown to lead to a dramatic increase in the concentration of demethyl-clomipramine, with a concomitant moderate increase in that of the parent drug. Deficient demethylation capacity is associated with a reduced ratio of demethyl metabolite to parent drug. A nomogram is provided to allow easy determination of hydroxylation and demethylation capacities from routinely measured blood concentrations. Data from 150 patients are analysed in order to identify interindividual variability factors. Average pseudo-clearances, calculated from trough blood concentrations at steady-state, are 17 L/h for hydroxylation, 23 L/h for demethylation and 40 L/h for elimination of hydroxylated metabolites. Maximum to minimum ratios are 8, 27 and 11, respectively. The metabolising capacity through either process significantly decreases with increasing age, clearance estimates being 40 to 50% lower for patients 75 years or older than for those 40 years or younger. Tobacco smoking and chronic alcohol consumption induce and reduce the demethylation clearance, respectively. Inhibition of hydroxylation in the presence of phenothiazine comedication is also shown. Finally, small but significant differences according to sex are observed. Potential implications of the proposed model-based approach include adaptation of the dosage regimen to individual characteristics at the very beginning of antidepressant therapy, and early detection of patients with impaired metabolising capacities.

Effects of ethanol on microsomal drug metabolism in aging female rats. III. In vivo

The effects of aging on ethanol inhibition of zoxazolamine metabolism in vitro and in vivo were studied in female Fischer 344 rats aged 4, 14 and 26 months. Zoxazolamine hydroxylase activity in freshly-isolated liver microsomes decreased significantly with age (1.88 +/- 0.32, 1.49 +/- 0.30 and 0.74 +/- 0.18 nmol/min per mg protein in young-adult, middle-aged and old rats, respectively). A substantial inhibition of zoxazolamine hydroxylation occurred in the presence of 40 mM ethanol. The extent of inhibition was the same in microsomes from all three age groups. The effect of aging on the duration of zoxazolamine paralysis in vivo reflected the effect of aging on zoxazolamine metabolism in vitro. Mean duration of paralysis following a standard 50 mg/kg dose of zoxazolamine increased significantly as a function of aging (0.5, 2.9 and 4.7 h in young-adult, middle-aged and old rats, respectively). Administration of ethanol (1.2 g/kg) 10 min before zoxazolamine treatment prolonged the duration of zoxazolamine paralysis in young-adult and middle-aged rats by about 2 to 2.5 h, but ethanol pretreatment did not affect paralysis time in old rats. Thus, the inhibitory effect of ethanol on zoxazolamine metabolism in vivo appeared to be attenuated in old age.

Effects of ethanol on microsomal drug metabolism in aging female rats. II. Inhibition

The effect of aging on the inhibition by ethanol of drug metabolism activity was examined in liver microsomes of female Fischer 344 rats aged 4, 14 and 24 months. Inhibition of aniline hydroxylase activity in microsomes from 4-month-old females occurred at low concentrations of ethanol (0.1 mM) and was predominantly competitive. Aging was associated with a significant increase in apparent Km for aniline in the absence of ethanol (24 +/- 2, 20 +/- 2 and 32 +/- 1 microM in microsomes from 4-, 14- and 24-month-old rats, respectively) and a change from competitive to non-competitive inhibition by ethanol. Inhibition of benzphetamine N-demethylase activity occurred only at high concentrations of ethanol (100 mM) and was non-competitive in nature. There were no significant effects of aging on the kinetics of the reaction or the type of inhibition produced by ethanol. Microsomal ethanol oxidation rates were measured in liver microsomes of 4-, 15- and 25-month-old Fischer 344 rats of both sexes. Ethanol oxidation in males was greater than in females and was decreased significantly in old age. Ethanol oxidation in female rats was unaffected by aging. The results suggest that significant changes in drug/ethanol interactions can occur as a consequence of aging.

Alcohol and drug interactions

Interactions of ethyl alcohol with various drugs are common. Their consequences vary depending on the effects of the drugs concerned, the doses of drugs and alcohol given and their mode of administration. Pharmacokinetic interactions refer to altered tissue concentrations of alcohol or drugs or both and their metabolites which sometimes lead to serious toxic reactions. The kinetic interactions take place in the absorption or metabolism of alcohol or the drug, whereas significant interactions in their distribution phase are rare. Pharmacodynamic interactions refer to the combined actions, even serious ones, which primarily take place at the tissue (receptor?) level, with or without an important pharmacokinetic component of interaction. Acute substantial doses of alcohol given quickly tend to inhibit microsomal drug metabolism and thus enhance the effects of drugs. Chronic administration of alcohol usually induces the synthesis of cytochrome P-450 isoenzyme P-450 II E1, thus accelerating the metabolism of its own and, depending on the circumstances, of various drugs as well. Reduced actions of the agents may then ensue. If the (toxic) effect of a drug (e.g., paracetamol) depends on the formation of active metabolites acute intake of alcohol may, paradoxically, reduce the drug effect, while chronic alcohol intake enhances it. Induction of hepatic enzymes by alcohol may affect the turnover of endogenous vitamins and hormones, or even produce carcinogenic substances.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic alcohol dehydrogenase activity in chick hepatocytes towards the major alcohols present in commercial alcoholic beverages: comparison with activities in rat and human liver

We have compared hepatic alcohol dehydrogenase activities in chick, rat and human liver with the major alcohols in commercial alcoholic beverages. 1. Chick and rat hepatic alcohol dehydrogenase was greater when assayed at a physiological pH in buffer containing chloride ions, as compared with the activity in pyrophosphate buffer at alkaline pH. 2. In contrast to reports of instability of ADH to freezing, we found the enzyme from all three species stable to freezing in 0.25 M sucrose. 3. Rat liver enzymatic activity was unstable in the presence of substrate, where as that of chick and human was not. 4. For all three species, the Km of hepatic ADH for substrate decreased with increasing chain length of alcohols. In both chick and human samples, the Vmax values for the higher chain alcohols were similar to that with ethanol, while in rat samples, ADH activity was dramatically lower with the higher chain alcohols compared to ethanol.

Combined effects of midazolam and ethanol on sleep and on psychomotor performance in normal subjects

A study was carried out on the effects of midazolam 15 mg in conjunction with ethanol 0.5 g/kg on objective and subjective sleep parameters and psychomotor performance in normal subjects. Midazolam significantly decreased total wake time. Total sleep time (TST) increase was related to larger amounts of stage 2 NREM sleep. Ethanol showed similar effects on sleep, although TST increase was associated with nonsignificant increments of NREM sleep and REM sleep. Ethanol slightly potentiated midazolam effects on sleep. Accordingly, total wake time, REM sleep time and number of wakes showed further depression than with midazolam alone. Subjective evaluations showed relatively good correlation with sleep laboratory findings. In addition, the different treatments did not impair subject's psychomotor performance the morning after their administration.

Purification and characterization of an ethanol-induced UDP-glucuronosyltransferase

A UDP-glucuronosyltransferase (GT) enzyme was isolated from ethanol-induced male New Zealand white rabbit hepatic protein. The animals were pretreated for 2 weeks with 10% ethanol in their drinking water. The GT enzyme was purified by anion-exchange and affinity chromatography and was shown to be homogeneous by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. The molecular mass of the ethanol-induced UDP-glucuronosyltransferase was determined to be 57,000 Da. Tryptic digests of the ethanol-induced GT and a similarly purified GT from control rabbit liver appeared to be different by HPLC analysis, even though the molecular masses of the enzymes were indistinguishable. Amino acid compositions of the two proteins were different for six amino acids. The apparent Km values for the ethanol-induced GT enzyme for 1-naphthol and morphine as substrates were 43 and 109 microM, respectively. The apparent Vmax values for the ethanol-induced GT enzyme for these substrates were 83 and 4.6 nmol/min/mg protein. The increases in catalytic efficiencies, apparent Vmax/Km for 1-naphthol and for morphine, for the ethanol-induced isozyme compared to the control isozyme activities were 2.0- and 2.4-fold. A polyclonal antibody raised in sheep to the rabbit ethanol-induced GT demonstrated a 520-fold selectivity for precipitation of the ethanol-induced protein rather than the control protein. These results demonstrate the production of an unique isozyme of UDP-glucuronosyltransferase that is produced in rabbits as a result of chronic ethanol exposure.

Effects of ethanol on microsomal drug metabolism in aging female rats. I. Induction

The purpose of this study was to determine how aging affects the induction by ethanol or acetone of the hepatic microsomal monooxygenase system of female Fischer 344 rats. Young-adult, middle-aged and old rats (4, 14 and 25 months) were fed an ethanol-containing or control liquid diet for 15 days. Cytochrome P-450, cytochrome c reductase, aniline hydroxylase, nitrophenol hydroxylase, nitroanisole O-demethylase and benzphetamine N-demethylase activities were measured in hepatic microsomes. All of the drug metabolism activities except benzphetamine N-demethylase were 20-35% lower in old than in young-adult rats fed the control diet. In addition, the increase in drug metabolism produced by feeding the regular ethanol diet (36% of calories as ethanol) was 50-60% lower in the old rats. However, there was no difference in the magnitude of ethanol induction when ethanol intakes were matched. The effects of chronic acetone consumption (1.2g/day per kg body weight for 15 days) paralleled those of ethanol consumption, except that the extent of induction was greater with acetone. Acetone-induced levels of hepatic microsomal cytochrome P-450, nitrophenol hydroxylase, nitroanisole O-demethylase and aniline hydroxylase were similar in all three age groups. The results of this study indicate that induction of hepatic microsomal drug metabolism by ethanol or acetone is unaffected by the aging process.

The treatment of alcohol withdrawal

Abrupt cessation of regular use of alcohol in a dependent person causes a withdrawal syndrome that may range from mild to extremely severe. Most patients require pharmacologic intervention, especially those with severe symptoms. Historically, the pharmacotherapy of alcohol withdrawal has involved a wide variety of agents. Benzodiazepines are currently preferred due to their consistently high degree of efficacy and laudable record of safety. In addition, beta blockers and clonidine are useful, as both effectively combat the hypertension and tachycardia commonly associated with withdrawal. They are ineffective as anticonvulsants; however. Opinions differ concerning the best treatment for withdrawal seizures. Prophylaxis with benzodiazepines may be all that is required, although some authors advocate the use of phenytoin for 5 days, especially in persons with a history of prior seizures during alcohol withdrawal. Once established, delirium tremens are difficult to treat. Benzodiazepines are most commonly used to provide sedation, and extremely large doses may be required. Careful clinical assessment is essential to the proper treatment of patients undergoing alcohol withdrawal since the coexistence of medical problems may complicate the condition.

Interaction of alcohol and transdermally administered scopolamine

In a placebo-controlled, randomized, double-blind cross-over study in 12 healthy volunteers the effect of acute alcohol intake during treatment with transdermally administered scopolamine (TTS-scopolamine) was investigated. One group of six subjects reached maximal blood alcohol concentrations (BAC) of 80 mg/dL and another group of six subjects a BAC of 130 mg/dL. There was no significant potentiation of alcohol effects on critical flicker fusion frequency by TTS-scopolamine. Sensorimotor function (choice reaction task) was also not significantly more influence by the combination. There was no effect of scopolamine on the elimination of alcohol. The urinary excretion of scopolamine was not influenced by oral intake of alcohol. TTS-scopolamine caused only minor side effects in a few volunteers, such as dry mouth (2 of 12) and blurred vision (1 of 12).

Experimental model for the investigation of kinetic and/or dynamic interactions between drugs and ethanol in humans

This study was performed to establish an experimental method for the investigation of interactions between ethanol and drugs under predictable and controlled conditions. The model was tested with flumazenil (Ro 15-1788), a short-acting benzodiazepine antagonist with an elimination half-life of 1 h. Six healthy volunteers (5 males, 1 female) were administered ethanol by intravenous infusion with stepwise changing rates. The infusion rates were adapted to each subject on the basis of individual disposition parameters of ethanol, which were derived from preceding short-term infusions of 120 min duration (1.0 mg/kg in males, 0.8 mg/kg in the female). This two-step procedure led to individual ethanol plasma levels between 1.47 +/- 0.04 and 1.71 +/- 0.03 g/L, which were reached after 2.5 h and thereafter maintained over another 6 h. Within the period of constant ethanol levels, single doses of flumazenil and placebo, respectively, were injected intravenously as a bolus (2 min) in a double-blind fashion according to a randomized two-way crossover design. Three subjects received a dose of 0.10 mg/kg of flumazenil, and the remaining three subjects received a dose of 0.20 mg/kg. Evaluation of the plasma concentration time curves of flumazenil did not reveal evidence of an effect of ethanol on the pharmacokinetics of this drug.

The influence of nutrition on the systemic availability of drugs. Part II: Drug metabolism and renal excretion

Plasma concentrations of an active compound vary between individuals and within a subject, even if the same drug dosage is used. These differences are related to variations of drug absorption from the gastrointestinal tract, of presystemic drug metabolism in the intestine or the liver, and of drug elimination from the systemic circulation, for instance by hepatic metabolism or renal excretion. All of these processes can be modified by nutrition. However it is necessary to emphasize the significance of the pharmaceutical formulation for variations of both drug absorption and elimination. The role of nutrition should receive adequate attention during therapeutic use of drugs as well as in drug disposition studies. Recent guidelines for the assessment of the systemic availability of drugs therefore do recommend nutrition to be controlled.

The effect of ethanol on serum cyclosporine A levels in renal transplant recipients

Following an alcohol binge, cyclosporine A (CyA) levels rose by 100% in a 51-year-old transplant recipient treated with CyA. As CyA and ethanol are both metabolized by the cytochrome P-450 enzyme system, ethanol could theoretically interfere with CyA metabolism. Therefore, eight male renal transplant recipients were assessed in a crossover study to determine the effects of acute ethanol ingestion on CyA serum concentrations. CyA serum concentrations did not rise following 50 mL of 100% alcohol. We conclude that heavy alcohol intake may increase CyA levels but that acute moderate intake does not.

Reinterpretation of the pharmacokinetic mechanism of oral benzodiazepine ethanol interaction

Previously published studies investigating the oral benzodiazepine ethanol interaction have utilized a single dose of ethanol, a single dose of oral benzodiazepine, and measured plasma benzodiazepine concentration over varying time periods. Most studies reported an increase or no change in benzodiazepine plasma concentrations following ethanol administration, which the investigators usually ascribed to an ethanol-induced increase in the benzodiazepine absorption rate constant. However, ethanol decreases the hepatic clearance of benzodiazepines that are biotransformed via the P450 enzyme system and this effect was not taken into account in evaluation of the results of these studies. Computer simulations have been used to investigate possible mechanisms of the oral benzodiazepine-ethanol interaction. The effects of a constant or transient decrease in clearance and an increase in absorption rate constant upon maximum concentration, time of maximum concentration, and area under the benzodiazepine plasma concentration curve (AUC) have been examined. A transient 75% decrease in benzodiazepine clearance resulted in a 13.6% increase in AUC (0-36 hr), a 3.4% increase in Cmax and a 5.7% increase in tmax. These changes are qualitatively consistent with, but quantitatively shy, of those observed in most studies. Consequently, an effect of ethanol upon benzodiazepine absorption must still be considered.