Cocaethylene formation following ethanol and cocaine administration by different routes

Ethanol alters the hepatic biotransformation of cocaine, resulting in transesterification to a novel active metabolite, cocaethylene. Because of first pass metabolism, oral drug administration might be expected to produce relatively larger concentrations of cocaethylene than would intravenous or smoked administration. We, therefore, compared the effects of route of cocaine administration on the formation and elimination of cocaethylene. Six experienced cocaine users were tested in 6 sessions, approximately 1 week apart. Deuterium-labeled cocaine (d₅) was administered in all conditions. Oral cocaine-d₅ 2.0 mg/kg, intravenous cocaine-d₅ 1.0 mg/kg, and smoked cocaine-d₅ (200 mg) were administered after oral ethanol 1.0 g/kg or placebo. A small, intravenous dose of deuterated cocaethylene (d₃) also was administered with all conditions for determination of cocaethylene formation. Physiologic and subjective effects were recorded and plasma cocaine-d₅, cocaethylene-d₅, cocaethylene-d₃, and benzoylecgonine-d₅ were measured by gas chromatography-mass spectrometry. About 24% (± 11) of intravenous cocaine was converted to cocaethylene. The oral route (34% ± 20) was significantly greater than from the smoked route (18% ± 11) and showed a trend toward significance for greater formation of cocaethylene compared to the intravenous route. Within each route, the cocaine-ethanol combination produced greater increases in heart rate and rate-pressure product than cocaine alone. Global intoxication effects across time after smoking or intravenous administration were significantly greater when cocaine and ethanol were both given. Administration of cocaine by different routes alters the amount of cocaethylene formed through hepatic first-pass effects. Increased cardiovascular and subjective effects might explain the toxicity and popularity of the combined drugs.

The clinical pharmacology of intranasal l-methamphetamine

Background

We studied the pharmacology of l-methamphetamine, the less abused isomer, when used as a nasal decongestant.

Methods

12 subjects self-administered l-methamphetamine from a nonprescription inhaler at the recommended dose (16 inhalations over 6 hours) then at 2 and 4 (32 and 64 inhalations) times this dose. In a separate session intravenous phenylephrine (200 μg) and l-methamphetamine (5 mg) were given to define alpha agonist pharmacology and bioavailability. Physiological, cardiovascular, pharmacokinetic, and subjective effects were measured.

Results

Plasma l-methamphetamine levels were often below the level of quantification so bioavailability was estimated by comparing urinary excretion of the intravenous and inhaled doses, yielding delivered dose estimates of 74.0 ± 56.1, 124.7 ± 106.6, and 268.1 ± 220.5 μg for ascending exposures (mean 4.2 ± 3.3 μg/inhalation). Physiological changes were minimal and not dose-dependent. Small decreases in stroke volume and cardiac output suggesting mild cardiodepression were seen.

Conclusion

Inhaled l-methamphetamine delivered from a non-prescription product produced minimal effects but may be a cardiodepressant.

Catecholamine response to methamphetamine is related to glucocorticoid levels but not to pleasurable subjective response

INTRODUCTION

Corticosteroids may modulate addiction. We previously described subjective, physiological, and endocrine effects of 0.5 mg/kg of intravenous methamphetamine after augmenting cortisol level with hydrocortisone or blocking cortisol response with the corticosteroid synthesis inhibitor metyrapone in a double-blind, balanced crossover study. Although the pharmacologic manipulations produced the expected hormonal changes, pleasurable subjective effects of methamphetamine were unchanged. Metyrapone was followed by frequent premature ventricular complexes (PVCs) in two subjects during methamphetamine administration. In order to better understand these results, we examined changes in two plasma catecholamine metabolites, homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG), and their relationship to the previously reported hormonal changes and physiological and subjective responses.

METHODS

Plasma from 10 methamphetamine subjects from the earlier study was assayed for HVA and MHPG by high performance liquid chromatography.

RESULTS

HVA levels were greater after hydrocortisone or metyrapone pretreatment compared to placebo, and MHPG levels were greater after metyrapone pretreatment. Hydrocortisone pretreatment diminished HVA and MHPG increases after methamphetamine (perhaps explaining the lack of expected increase in pleasurable effects), but metyrapone did not. HVA and MHPG concentrations were not correlated with pleasurable drug effects but were inversely related to reports of "Bad Drug Effect." Increases in MHPG and DHEA concentrations were positively correlated. Metyrapone pre-treated subjects with PVCs had lower HVA and MHPG concentrations.

CONCLUSION

Raising cortisol concentration and blocking cortisol synthesis did not produce opposite effects, perhaps because of metyrapone's effect on the hypothalamic-pituitary-adrenal axis, its stress-like effects, and its effects on neurosteroids.

Expanding treatment of tobacco dependence

Nicotine dependence is the leading preventable cause of adult morbidity and mortality in the world. New research on the treatment of this disorder ranges from studies evaluating access to treatment to studies elucidating the molecular mechanisms of nicotine addiction. As our understanding of the neurobiology of tobacco addiction grows, the number of potential therapeutic targets by which we can intervene in this pernicious disorder also increases. This paper presents an overview of recent research trends in the treatment of tobacco dependence. We review several novel mechanisms of action that may serve as therapeutic targets for the pharmacologic treatment of tobacco dependence, including drugs that affect monamine oxidase, selective nicotinic receptors, glutamate and gamma-aminobutyric acid receptors, and the endocannabinoid system. For each of these therapeutic targets, we discuss medications in development that affect these pathophysiologic mechanisms.

Repeated psychological stress testing in stimulant-dependent patients

Decreasing response to stress has been one goal of interventions aimed at reducing relapse to substances of abuse. A laboratory stress test that can be repeated would be helpful in testing the efficacy of interventions in decreasing the response to stress before more extensive trials are begun. The effects of two types of psychological stress tests, the Trier Social Stress Test (TSST) and a stress imagery test, on psychological, physiological, and hormonal responses (salivary cortisol and DHEA) were examined when each test was given twice to cocaine- or methamphetamine-dependent human subjects, 24 of whom completed at least one session. The stress imagery test produced significant changes in several of the subjective response measures in both first and second sessions, including several measures of negative affect and a craving measure. The TSST produced significant changes only in the second session. The stress imagery protocol showed better replicability across two sessions. Cocaine users and methamphetamine users did not respond similarly in their craving responses. Reported craving for methamphetamine after stress testing showed decreases or much smaller increases compared to that for cocaine. Neither stress test significantly increased salivary cortisol or DHEA, and changes in hormone concentrations were not related to subjective responses. These results suggest that stress imagery testing procedures may be useful as provocative tests of stress-induced affect and stimulant drug craving. Although less convincing because of the heterogeneity of the subjects, they also suggest that HPA axis responsivity is not clearly linked to acute stress-induced stimulant craving or affective response.

Fluoxetine attenuates adrenocortical but not subjective responses to cocaine cues

Preclinical data suggest a link between stress reactivity and cocaine self-administration by rodents. Serotonin appears to modulate the hypothalamic-pituitary-adrenal (HPA) axis. We studied the effects of chronic treatment with the serotonin reuptake inhibitor fluoxetine 40 mg/day on subjective and hormonal responses to cocaine cues in 22 subjects participating in a controlled clinical trial for cocaine dependence. Fluoxetine antagonized the cue-induced increase in cortisol but increased subjects' ratings of the likelihood of cocaine use in response to cocaine cues. Cortisol response to cocaine cues was not related to subjective craving. Activation of the HPA axis by cocaine cues does not appear to be a necessary mediator of cue-induced craving.

Quantitative drug levels in stimulant psychosis: relationship to symptom severity, catecholamines and hyperkinesia

To examine the relationship between quantitative stimulant drug levels, catecholamines, and psychotic symptoms, nineteen patients in a psychiatric emergency service with a diagnosis of amphetamine- or cocaine-induced psychosis were interviewed, and plasma and urine were collected for quantitative assays of stimulant drug and catecholamine metabolite levels. Methamphetamine or amphetamine levels were related to several psychopathology scores and the global hyperkinesia rating. HVA levels were related to global hyperkinesia but not to psychopathology ratings. Although many other factors such as sensitization may play a role, intensity of stimulant-induced psychotic symptoms and stereotypies appears to be at least in part dose-related.

Pharmacokinetics and Subjective Effects of Sublingual Buprenorphine, Alone or in Combination with Naloxone

OBJECTIVE

Buprenorphine and buprenorphine/naloxone combinations are effective pharmacotherapies for opioid dependence, but doses are considerably greater than analgesic doses. Because dose-related buprenorphine opioid agonist effects may plateau at higher doses, we evaluated the pharmacokinetics and pharmacodynamics of expected therapeutic doses.

DESIGN

The first experiment examined a range of sublingual buprenorphine solution doses with an ascending dose design (n = 12). The second experiment examined a range of doses of sublingual buprenorphine/naloxone tablets along with one dose of buprenorphine alone tablets with a balanced crossover design (n = 8).

PARTICIPANTS

Twenty nondependent, opioid-experienced volunteers.

METHODS

Subjects in the solution experiment received sublingual buprenorphine solution in single ascending doses of 4, 8, 16 and 32 mg. Subjects in the tablet experiment received sublingual tablets combining buprenorphine 4, 8 and 16 mg with naloxone at a 4 : 1 ratio or buprenorphine 16 mg alone, given as single doses. Plasma buprenorphine, norbuprenorphine and naloxone concentrations and pharmacodynamic effects were measured for 48-72 hours after administration.

RESULTS

Buprenorphine concentrations increased with dose, but not proportionally. Dose-adjusted areas under the concentration-time curve for buprenorphine 32 mg solution, buprenorphine 1 6 mg tablet and buprenorphine/naloxone 16/4 mg tablet were only 54 +/- 16%, 70 +/- 25% and 72 +/- 17%, respectively, of that of the 4 mg dose of sublingual solution or tablet. No differences were found between dose strengths for most subjective and physiological effects. Pupil constriction at 48 hours after administration of solution did, however, increase with dose. Subjects reported greater intoxication with the 32 mg solution dose, even though acceptability of the 4 mg dose was greatest. Naloxone did not change the bioavailability or effects of the buprenorphine 16 mg tablet.

CONCLUSION

Less than dose-proportional increases in plasma buprenorphine concentrations may contribute to the observed plateau for most pharmacodynamic effects as the dose is increased.

The pharmacology of cocaethylene in humans following cocaine and ethanol administration

BACKGROUND

Concurrent use of cocaine and alcohol results in formation of a cocaine homolog and metabolite-cocaethylene.

METHODS

To characterize cocaethylene pharmacology, ten paid volunteer subjects were given deuterium-labeled (d(5)) cocaine (0.3, 0.6, and 1.2 mg/kg and cocaine placebo) by a 15-min constant rate intravenous injection 1 h after a single oral dose of ethanol (1 g/kg) or ethanol and cocaine placebo using a double-blind, crossover design. Six of the same volunteers subsequently received a 1.2 mg/kg dose of cocaine alone. A small (7.5 mg) nonpharmacologically active dose of deuterium-labeled cocaethylene-d(3) was concurrently administered with the cocaine to enable calculation of absolute cocaethylene formation and clearance. Plasma and urine cocaine, cocaethylene, and benzoylecgonine concentrations, physiologic and subjective effects were measured.

RESULTS

When co-administered with ethanol, 17+/-6% (mean+/-S.D.) of the cocaine was converted to cocaethylene. Cocaethylene peak plasma concentrations and AUC increased proportionally to the cocaine dose. Ethanol ingestion prior to cocaine administration decreased urine benzoylecgonine levels by 48% and increased urinary cocaethylene and ecgonine ethyl ester levels. Subjects liked and experienced more total intoxication after the combination of cocaine and ethanol than after either drug alone.

CONCLUSIONS

In the presence of ethanol, the altered biotransformation of cocaine resulted in 17% of an intravenous cocaine dose being converted to cocaethylene and relatively lower urinary concentrations of benzoylecgonine.

The bioavailability of intranasal and smoked methamphetamine

BACKGROUND

Patients in harm-reduction treatment programs are switching from intravenous to other routes of methamphetamine (INN, metamfetamine) administration to avoid risks associated with needle use. Relatively little has been reported about the bioavailability of methamphetamine when smoked or used intranasally.

METHODS

Eight experienced methamphetamine users were administered smoked or intranasal methamphetamine concurrently with an intravenous dose of deuterium-labeled methamphetamine. Plasma and urine concentrations were measured for calculation of bioavailability and other pharmacokinetic parameters by noncompartmental methods.

RESULTS

Methamphetamine was well absorbed after smoking or intranasal administration, with bioavailabilities of 79% after intranasal administration and 67% of the estimated delivered dose or 37.4% of the absolute (pipe) dose after smoking. Maximum methamphetamine concentrations occurred at 2.7 and 2.5 hours after intranasal and smoked doses. The elimination half-life was similar for intravenous (11.4 hours), intranasal (10.7 hours), and smoked (10.7 hours) methamphetamine. Clearance (272 mL x h(-1) x kg(-1)), steady-state volume of distribution (4.2 L/kg), and mean residence time (16 hours) of the intravenous dose were similar to previously reported values. Dextroamphetamine (INN, dexamfetamine) half-life (all routes) was 16.2 hours. Methamphetamine and dextroamphetamine renal clearances (all routes) were about 100 and 1100 mL x h(-1) x kg(-1), respectively.

CONCLUSIONS

Intranasal and smoked methamphetamine are well absorbed. Although intranasal or smoked routes may decrease the risk of transmission of blood-borne diseases, exposure to methamphetamine and the possibility of drug-related complications remain substantial.

Altering cortisol level does not change the pleasurable effects of methamphetamine in humans

Preclinical studies have linked corticosteroid secretion and levels with drug self-administration by animals. In a double-blind, cross-over study, subjective, physiological, and endocrine responses to intravenous doses of methamphetamine 0.5 mg/kg or placebo were assessed in eight methamphetamine-experienced subjects after three cortisol-modifying premedication conditions: augmenting cortisol level with oral hydrocortisone 50 mg, blocking cortisol response with the corticosteroid synthesis inhibitor metyrapone 1500 mg orally, or no premedication. Although the pharmacologic manipulations produced the expected hormonal changes, subjective response to the methamphetamine showed few differences. Diminishing cortisol response by pharmacologic blockade did not alter the pleasurable effects of methamphetamine. Hydrocortisone did increase self-reported 'bad drug effect' and decreased craving after saline placebo relative to the period following methamphetamine. Metyrapone was associated with significant premature ventricular complexes in two subjects during methamphetamine administration and may not be safe for those who use methamphetamine.

Subjective and hormonal effects of 3,4-methylenedioxymethamphetamine (MDMA) in humans

RATIONALE

3,4-Methylenedioxymethamphetamine (MDMA) is a widely used phenethylamine. Reports have described the effects of MDMA in a controlled laboratory setting, but the full range of effects of MDMA in humans is still not completely characterized.

OBJECTIVES

To describe the physiological, subjective, and hormonal changes after single doses of MDMA in a laboratory setting and examine relationships between these effects.

METHODS

Eight MDMA-experienced volunteers each received placebo, 0.5 mg/kg, and 1.5 mg/kg oral doses of MDMA in a double-blind crossover study.

RESULTS

The 1.5 mg/kg dose (comparable to that typically used by most participants) produced significant subjective effects, peaking at about 2 h after dosing, including some effects commonly associated with stimulant drugs, hallucinogens, and entactogens. MDMA significantly increased plasma cortisol, prolactin, and dehydroepiandrosterone (DHEA) levels. Increase in plasma cortisol after the 1.5 mg/kg dose correlated with increased heart rate, rate-pressure product, and drug liking. Rise in DHEA correlated with euphoria.

CONCLUSIONS

A typically used dose of MDMA produced effects commonly associated with stimulants and hallucinogens. Subjects liked MDMA. Correlations between cortisol and DHEA levels and some physiological and psychological effects are consistent with animal data suggesting that hormones modulate some responses to drugs of abuse.

Movement disorder, memory, psychiatric symptoms and serum DHEA levels in schizophrenic and schizoaffective patients

OBJECTIVE

Reports of low levels of dehydroepiandrosterone (DHEA) or its sulphate (DHEA-S) in some schizophrenic patients and in some persons with poorer motoric and cognitive functioning led us to examine clinical correlates of serum DHEA and DHEA-S levels in schizophrenic patients.

METHOD

Ratings of abnormal movements, memory and psychiatric symptoms in 17 medicated chronic schizophrenic or schizoaffective inpatients at a state hospital were correlated with serum DHEA and DHEA-S levels, and their ratios with serum cortisol.

RESULTS

Controlling for age, higher DHEA levels and/or higher DHEA/cortisol ratios were significantly correlated with lower symptom ratings on the Brief Psychiatric Rating Scale, better performance on some measures of memory, and lower ratings of parkinsonian symptoms.

CONCLUSION

Relatively low DHEA levels or DHEA/cortisol ratios may identify a particularly impaired subgroup of medicated patients with chronic schizophrenia. Potential implications are discussed.

Buprenorphine and naloxone co-administration in opiate-dependent patients stabilized on sublingual buprenorphine

Buprenorphine and naloxone sublingual (s.l.) dose formulations may decrease parenteral buprenorphine abuse. We evaluated pharmacologic interactions between 8 mg s.l. buprenorphine combined with 0, 4, or 8 mg of naloxone in nine opiate-dependent volunteers stabilized on 8 mg s.l. buprenorphine for 7 days. Combined naloxone and buprenorphine did not diminish buprenorphine's effects on opiate withdrawal nor alter buprenorphine bioavailability. Opiate addicts stabilized on buprenorphine showed no evidence of precipitated opiate withdrawal after s.l. buprenorphine-naloxone combinations. Buprenorphine and naloxone bioavailability was approximately 40 and 10%, respectively. Intravenous buprenorphine and naloxone produced subjective effects similar to those of s.l. buprenorphine and did not precipitate opiate withdrawal.

Extending the Fatigue Severity Scale to an obese population

The Fatigue Severity Scale (FSS) is a self-report instrument used to assess levels of fatigue and its effect on daily functioning. The FSS was normed on individuals with multiple sclerosis and has been used in studies examining such factors as obstructive sleep apnea and aerobic exercise. Current research has extended it to obese subjects to assess their level of fatigue in conjunction with a 16-week obesity treatment program. Participants were 118 females with an average age of 45.24 (SD = 11.44). The results yield high pre- and post-test reliability for the FSS and weight loss.

Peripherally inserted central catheters: placement and use in a family practice hospital

BACKGROUND

The peripherally inserted central catheter (PICC) is increasingly used in protracted intravenous therapy. The device has several advantages for family practice, but its use has been chiefly described in nursing and interventional radiology literature. We investigated the use of the PICC in a family practice teaching hospital.

METHODS

Forty PICCs were inserted from 1993 to 1995 in 29 patients. Available records and radiographs were reviewed for indication, nature of placement attempts, indwelling time, PICC role in therapy, and attendant complications.

RESULTS

Successful placement was achieved in 95 percent of instances requiring PICC use. Fluoroscopically guided placement, usually without venography, was found to be preferable to unguided bedside placement. In a few cases in which PICCs were placed, no other access was subsequently required to complete therapy. Few clinically serious complications were encountered. Most complications were related to placement at bedside.

CONCLUSIONS

Our experience supports the PICC as a minimally invasive, economical alternative for protracted intravenous therapy. Fluoroscopically guided placement was found preferable to unguided bedside placement. Physicians ordering or placing PICCs should understand fully how to assess placement.

Polarized distribution of glucose transporter isoforms in Caco-2 cells

We have examined the expression and cellular location of facilitated glucose transporter proteins (GLUT1, -3, and -5) in a human colonic epithelial cell line (Caco-2) by using peptide-specific antibodies. A differential cellular distribution of these transporters was observed in differentiated (greater than 14 days postconfluence) Caco-2 cells by immunofluorescence and immunoelectron microscopy. GLUT1 was localized primarily to the basolateral membrane, whereas GLUT3 was predominantly localized to the apical membrane. GLUT5, which was detected in only approximately 40% of fully differentiated Caco-2 cells, was found primarily in the apical membrane but was also present in both basolateral and intracellular membranes. A Na(+)-independent glucose transport system in the apical membrane of Caco-2 cells has been described previously [Blais, A., Bissonnette, A. & Berteloot, A. (1987) J. Membr. Biol. 99, 113-125], and we propose that GLUT3 mediates this process. The amino acid sequence identity (57%) and structural conservation between GLUT1 and GLUT3 may make these transporters an ideal model system for examining the molecular basis for polarized sorting of membrane proteins.

Translocation of the glucose transporter (GLUT4) to the cell surface in permeabilized 3T3-L1 adipocytes: effects of ATP insulin, and GTP gamma S and localization of GLUT4 to clathrin lattices

Insulin stimulates the movement of two glucose transporter isoforms (GLUT1 and GLUT4) to the plasma membrane (PM) in adipocytes. To study this process we have prepared highly purified PM fragments by gently sonicating 3T3-L1 adipocytes grown on glass coverslips. Using confocal laser immunofluorescence microscopy we observed increased PM labeling for GLUT1 (2.3-fold) and GLUT4 (eightfold) after insulin treatment in intact cells. EM immunolabeling of PM fragments indicated that in the nonstimulated state GLUT4 was mainly localized to flat clathrin lattices. Whereas GLUT4 labeling of clathrin lattices was only slightly increased after insulin treatment, labeling of uncoated PM regions was markedly increased with insulin. These data suggest that GLUT4 recycles from the cell surface both in the presence and absence of insulin. In streptolysin-O permeabilized adipocytes, insulin, and GTP gamma S increased PM levels of GLUT4 to a similar extent as observed with insulin in intact cells. In the absence of an exogenous ATP source the magnitude of these effects was considerably reduced. Removal of ATP per se caused a significant increase in cell surface levels of GLUT4 suggesting that ATP may be required for intracellular sequestration of these transporters. When insulin and GTP gamma S were added together, in the presence of ATP, PM GLUT4 levels were similar to levels observed when either insulin or GTP gamma S was added individually. Addition of GTP gamma S was able to overcome this ATP dependence of insulin-stimulated GLUT4 movement. GTP gamma S had no effect on constitutive secretion of adipsin in permeabilized cells. In addition, there was no effect of insulin or GTP gamma S on GLUT4 movement to the PM in noninsulin sensitive streptolysin-O-permeabilized 3T3-L1 fibroblasts overexpressing GLUT4. We conclude that the insulin-stimulated movement of GLUT4 to the cell surface in adipocytes may require ATP early in the insulin signaling pathway and a GTP-binding protein(s) at a later step(s). We propose that the association of GLUT4 with clathrin lattices may be important in maintaining the exclusive intracellular location of this transporter in the absence of insulin.