Overview of HOMEChem: House Observations of Microbial and Environmental Chemistry.

The House Observations of Microbial and Environmental Chemistry (HOMEChem) study is a collaborative field investigation designed to probe how everyday activities influence the emissions, chemical transformations and removal of trace gases and particles in indoor air. Sequential and layered experiments in a research house included cooking, cleaning, variable occupancy, and window-opening. This paper describes the overall design of HOMEChem and presents preliminary case studies investigating the concentrations of reactive trace gases, aerosol particles, and surface films. Cooking was a large source of VOCs, CO2, NOx, and particles. By number, cooking particles were predominantly in the ultrafine mode. Organic aerosol dominated the submicron mass, and, while variable between meals and throughout the cooking process, was dominated by components of hydrocarbon character and low oxygen content, similar to cooking oil. Air exchange in the house ensured that cooking particles were present for only short periods. During unoccupied background intervals, particle concentrations were lower indoors than outdoors. The cooling coils of the house ventilation system induced cyclic changes in water soluble gases. Even during unoccupied periods, concentrations of many organic trace gases were higher indoors than outdoors, consistent with housing materials being potential sources of these compounds to the outdoor environment. Organic material accumulated on indoor surfaces, and exhibited chemical signatures similar to indoor organic aerosol.

Effect of opioid dependence pharmacotherapies on zidovudine disposition.

Injection drug users are frequently infected with human immunodeficiency virus (HIV) and receive opioid dependence pharmacotherapies and zidovudine (ZDV), the latter as a component of highly active antiretroviral therapy. We previously reported that methadone substantially increases ZDV concentrations. We now report on oral ZDV pharmacokinetics in 52 subjects receiving the opioid dependence pharmacotherapies l-alpha-acetylmethadol LAAM, buprenorphine, or naltrexone, and 17 non-opioid-treated controls. Relative to the area under the time-concentration curve (AUC) of ZDV in control subjects, no statistically significant differences in ZDV AUC were observed in participants treated with LAAM (p = .75), buprenorphine (p = .37), or naltrexone (p = .34). While methadone maintenance may result in ZDV toxicity and possibly require dose adjustments, other opioid pharmacotherapies should not produce ZDV toxicity.

Sex differences in self-reported and physiological response to oral cocaine and placebo in humans.

Self-report and physiological data from 27 male and 8 female cocaine-abusing volunteers exposed to cocaine (80 mg/70 kg p.o.) and placebo were examined for sex differences in their responses. Females reported significantly greater baseline ratings on the Pentobarbital-Chlorpromazine-Alcohol Group (PCAG) (sedation) and Lysergic Acid Diethylamide (LSD) (dysphoria) subscales of the Addiction Research Center Inventory-Short Form (ARCI) relative to males. In addition, females reported significantly greater ratings on the Visual Analogs Scales (VAS) Bad Drug Effects and Anxious/Nervous scales relative to males, regardless of drug. Cocaine produced greater increase in systolic blood pressure in males following cocaine, whereas females showed greater increases following placebo. These results suggest that a placebo control is necessary to determine sex differences in response to an active drug.

Interaction of methadone with didanosine and stavudine.

For opiate-dependent injection drug users infected with HIV, methadone therapy may facilitate adherence to complex highly active antiretroviral therapy (HAART) regimens. Current HAART regimens include one or more nucleoside analogues. We investigated the effects of methadone on the pharmacokinetics of the tablet formulation of didanosine (ddI) and of stavudine (d4T) in 17 study subjects on stable methadone therapy and in 10 untreated controls. Methadone treatment reduced the measured areas under the time-concentration curve (AUC0-6) by 63% for ddI (p =.04) and by 25% for d4T (p =.005) and the extrapolated AUCs for the full dosing interval (AUC0-12) by 57% for ddI (p =.11) and by 23% for d4T (p =. 02). Peak drug concentrations (Cmax) were reduced by 66% (p =.007) and 44% (p =.001) for ddI and d4T, respectively. The effects on AUC and Cmax appeared to result primarily from decreases in bioavailability. Methadone also delayed drug absorption. Trough levels for methadone did not differ significantly from those in historical controls, suggesting that ddI and d4T did not substantially alter methadone disposition. The results suggest that larger doses of the tablet formulation or an alternate formulation may be needed when didanosine is given to study subjects treated with methadone.

Comparison of intravenous cocaethylene and cocaine in humans.

RATIONALE: Cocaethylene is a pharmacologically active homolog and metabolite of cocaine, formed by transesterification of cocaine in the presence of ethanol. Here we relate findings from a randomized, placebo-controlled, double-blind study in which we examined the physiological and subjective effects and pharmacokinetics of i.v. administered cocaethylene in human volunteers using cocaine as a comparator. METHODS: Cocaine-dependent participants randomly received one study drug, cocaethylene (0.25 or 0.5 mg/kg), cocaine (0.25 or 0.5 mg/kg), or placebo, during each experimental session which occurred on separate days. RESULTS: Cocaethylene was less potent in elevating heart rate than equivalent doses of cocaine. Similar differences between cocaine and cocaethylene were found for subjective measures ("Cocaine High", "Rush", "Stimulated" and "Good Drug Effects"). All active drug conditions produced significant increases in systolic blood pressure relative to placebo, but no significant effect on diastolic blood pressure was observed. Cocaethylene demonstrated a slower clearance, larger volume of distribution and correspondingly longer elimination half-life than cocaine. CONCLUSION: The findings from this study confirm those of previous studies that show that cocaethylene has pharmacological properties in common with cocaine, but is less potent.

Disulfiram treatment for cocaine dependence in methadone-maintained opioid addicts.

AIMS: Cocaine use by patients on methadone maintenance treatment is a widespread problem and is associated with a poorer prognosis. Recent studies have evaluated disulfiram as a treatment for individuals with comorbid alcohol and cocaine abuse. We evaluated the efficacy of disulfiram for cocaine dependence, both with and without co-morbid alcohol abuse, in a group of methadone-maintained opioid addicts. DESIGN: Randomized double-blind, placebo-controlled trial. SETTING: Urban methadone maintenance clinic. PARTICIPANTS: Sixty-seven cocaine-dependent, methadone-maintained, opioid-dependent subjects (52% female; 51% Caucasian). INTERVENTION: Study medication, either disulfiram or placebo, was placed directly in the methadone to ensure compliance for 12 weeks. MEASUREMENTS: Primary outcome measures included weekly assessments of the frequency and quantity of drug and alcohol use, weekly urine toxicology screens and breathalyzer readings. FINDINGS: Disulfiram treated subjects decreased the quantity and frequency of cocaine use significantly more than those treated with placebo. Alcohol use was minimal for all subjects regardless of the medication. CONCLUSIONS: Disulfiram may be an effective pharmacotherapy for cocaine abuse among methadone-maintained opioid addicts, even in those individuals without co-morbid alcohol abuse. Disulfiram inhibits dopamine beta-hydroxylase resulting in an excess of dopamine and decreased synthesis of norepinephrine. Since cocaine is a potent catecholamine re-uptake inhibitor, disulfiram may blunt cocaine craving or alter the "high", resulting in a decreased desire to use cocaine.

Effects of lamotrigine on behavioral and cardiovascular responses to cocaine in human subjects.

We evaluated the effects of acute pretreatment with lamotrigine, a putative glutamate release inhibitor, on the physiological and behavioral responses to intranasal cocaine in cocaine-dependent volunteers (N = 8). The study employed a double-blind, placebo-controlled, within-subject design. Subjects participated in six experimental sessions. On each study day, placebo, lamotrigine 125 mg, or lamotrigine 250 mg was administered orally in the morning, followed 2 hours later by intranasal cocaine 120 mg/70 kg or placebo. Measurements of heart rate and blood pressure were acquired, and subjects responded to mood state questionnaires at predetermined time intervals. Cocaine alone produced increases in heart rate, blood pressure, and several measures of pleasurable mood and drug effects. Lamotrigine alone produced a mild relaxing effect. Lamotrigine pretreatment altered neither the physiological responses nor the subjective ratings of cocaine's pleasurable or aversive mood effects.

Improving the quality of substance dependency treatment with pharmacotherapy.

This article provides an overview of current pharmacological treatments for alcohol, opioid, cocaine, and nicotine use disorders. Guidelines for a "patient-treatment" matching framework to physicians working with various "substance-abusing" patients are presented, as well as recommendations regarding when to initiate and discontinue pharmacotherapy. Standard and newer pharmacological treatments for substance dependence are reviewed, as well as therapies that may be especially useful when treating the patient with comorbid substance dependency and psychiatric disorders. To maximize the therapeutic benefits of substance dependency treatment, patients should be individually assessed and provided adjunctive medications as clinically indicated. Specific areas for future laboratory and/or clinical research are recommended.

Gender differences in treatment-seeking cocaine abusers--implications for treatment and prognosis.

This study examined gender differences in demographics, psychosocial functioning, substance abuse severity, psychopathology, and 1-year outcome in cocaine-dependent patients with the goal of identifying factors important to improving treatment and identifying prognostic indicators. The sample included 298 cocaine-dependent adults (92 women). Ninety-four patients (29 women) provided 1-year follow-up assessments. Compared to men, women consumed similar quantities of cocaine by more addictive routes and experienced more rapid progression of drug dependence, thus highlighting the need to facilitate treatment entry. The substantial rates of positive treatment outcomes emphasizes the effectiveness of treatment for cocaine-dependent individuals.

Individual differences in humans responding under a cocaine discrimination procedure: discriminators versus nondiscriminators.

Twenty-six cocaine-abusing volunteers were trained to discriminate cocaine (80 mg/70 kg, p.o.) from placebo. On the basis of a discrimination acquisition criterion (i.e., >80% drug-appropriate responding for 4 consecutive sessions within 8-10 sessions), 18 participants were classified as discriminators (Ds) and 8 as nondiscriminators (NDs). Relative to Ds, NDs reported a greater amount of cocaine use per time. During the training phase, NDs showed significantly lower ratings than Ds on a stimulant ratings scale, regardless of the training drug condition. During the test-of-acquisition phase, cocaine-induced increases in scores on ratings of drug strength, anxious-nervous and cocaine high, as well as on a euphoria ratings scale, were significantly greater in Ds than NDs, relative to placebo. These results suggest that drug use history, general arousal level, and drug sensitivity may be important variables influencing the acquisition of cocaine versus placebo discrimination in cocaine abusers.

Disulfiram effects on acute cocaine administration.

Disulfiram (Antabuse) is being used in outpatient clinical trials to determine its efficacy as a treatment for cocaine dependence. This inpatient randomized, double-blind, placebo-controlled, within-subjects study was conducted to determine whether disulfiram (placebo, 250 or 500 mg/day) alters responses to acute intranasal cocaine (placebo, 1 or 2 mg/kg) administration. Effects of disulfiram on cocaine pharmacokinetics, physiological, and behavioral responses were determined. Disulfiram treatment increased plasma cocaine concentrations three to six times and significantly increased cocaine-associated cardiovascular responses, but did not significantly alter behavioral responses to cocaine. These interactions should be considered in the decision regarding disulfiram treatment in cocaine dependent patients.

Methadone effects on zidovudine disposition (AIDS Clinical Trials Group 262).

Large numbers of injection drug users (IDUs) are infected with HIV and receive both methadone and zidovudine (ZDV) therapy. Pharmacokinetic interactions between these agents may effect drug efficacy, toxicity, and compliance. To confirm and expand previous studies that identified a potential interaction between ZDV and methadone, we performed a within-subject study to determine oral and intravenous ZDV pharmacokinetics in 8 recently detoxified, heroin-addicted patients with HIV disease before and after initiation of methadone treatment. Acute methadone treatment increased oral ZDV in the area under the curve (AUC) by 41% (p = .03) and intravenous ZDV AUC by 19% (p = .06). Clearance was reduced by 21% (p = .007) and 19% (p = .04), respectively. Chronic methadone treatment increased oral ZDV AUC by 29% (p = .15) and intravenous ZDV AUC by 41% (p = .05). Clearance was decreased by 26% for both routes (p = .02). Methadone levels remained in the therapeutic range during ZDV treatment. These effects resulted primarily from inhibition of ZDV glucuronidation, but also from decreased renal clearance of ZDV. This study confirms that methadone-maintained patients receiving standard ZDV doses experience greater ZDV exposure and may be at increased risk for ZDV side effects and toxicity. Increased toxicity surveillance and possibly reduction in ZDV dose are indicated when these two agents are given concomitantly.

Concurrent use of cocaine and alcohol is more potent and potentially more toxic than use of either alone--a multiple-dose study.

BACKGROUND: Simultaneous abuse of cocaine and alcohol is widespread and increasingly detected in patients seeking emergent care. This double-blind, randomized, within-subjects study used a paradigm more closely approximating practices of drug abusers to better understand the pathogenesis of cocaine-alcohol abuse. METHODS: Subjects meeting DSM-IV criteria for cocaine dependence and alcohol abuse participated in three drug administration sessions: four doses of intranasal cocaine (1 mg/kg every 30 min) with oral alcohol (1 g/kg) administered following the initial cocaine dose and a second dose (120 mg/kg) at 60 min calculated to maintain plasma alcohol concentration at approximately 100 mg/dL during cocaine administration; four doses of cocaine/placebo alcohol; four doses of cocaine placebo/alcohol. Pharmacokinetic, physiological, and behavioral effects were followed over 8 hours. RESULTS: Cocaine-alcohol produced greater euphoria and increased perception of well-being relative to cocaine. Heart rate significantly increased following cocaine-alcohol administration relative to either drug alone. Cocaine concentrations were greater following cocaine-alcohol administration. Cocaethylene had a longer halflife with increasing concentrations relative to cocaine at later time points. CONCLUSIONS: Enhanced psychological effects during cocaine-alcohol abuse may encourage ingestion of larger amounts of these substances over time placing users at heightened risk for greater toxicity than with either drug alone.

Chronic disulfiram treatment effects on intranasal cocaine administration: initial results.

BACKGROUND: Simultaneous abuse of cocaine and alcohol is common. Alcohol decreases negative stimulant effects and potentiates "high." Disulfiram (Antabuse) is being studied in outpatient trials as a cocaine pharmacotherapy with the rationale that inability to modulate cocaine effects with alcohol may decrease cocaine use. METHODS: We examined the interaction of disulfiram and cocaine in a randomized, double-blind, placebo-controlled study where subjects were chronically treated with disulfiram and then participated in intranasal cocaine administration studies. RESULTS: Disulfiram 250 mg/day treatment significantly increased plasma cocaine concentrations (p = .013), heart rate (cocaine 1 mg/kg, p = .046), and systolic (cocaine 2 mg/kg p = .003) and diastolic (cocaine 2 mg/kg, p = .022) blood pressure. "High" and "nervous" ratings were nonsignificantly increased. CONCLUSIONS: The combination of "high" with increased anxiety in the context of inability to lessen negative effects with alcohol may be an effective treatment in selected patients. The significant pharmacokinetic interaction must be considered in the decision regarding use of disulfiram.

Neurobiology of tryptophan depletion in depression: effects of m-chlorophenylpiperazine (mCPP).

This study utilized neuroendocrine and mood responses to intravenous (i.v.) infusion of the serotonin (5-HT) agonist m-chlorophenylpiperazine (mCPP) to evaluate central 5-HT function in depressed patients undergoing acute tryptophan (TRP) depletion. Twenty-two drug-free patients with DSM-III-R major depression participated. Each patient underwent two randomized, double-blind TRP depletion tests, one sham and one active. At the estimated time of maximum TRP depletion, each patient received an i.v. infusion of mCPP 0.1 mg/kg. Blood was obtained for serum cortisol, prolactin, and growth hormone. Multiple rating scales were used to assess mood. The cortisol response to i.v. mCPP was significantly greater during TRP depletion than during sham depletion, and free plasma TRP was negatively correlated with the cortisol response during TRP depletion. These findings are consistent with the hypothesis that acute TRP depletion in drug-free depressed patients induces a compensatory up-regulation of postsynaptic 5-HT receptors, most likely of the 5-HT2A/2C subtype. Such changes suggest a mechanism by which acute and potent manipulations of 5-HT function in depressed patients could be used to effect rapid clinical improvement.

Concurrent cocaine-ethanol ingestion in humans: pharmacology, physiology, behavior, and the role of cocaethylene.

Simultaneous abuse of cocaine and ethanol is a common occurrence. Cocaethylene, the ethyl ester of benzoylecgonine, has been detected in the urine of patients reporting concurrent use of cocaine and ethanol, and high levels have been found in the blood of victims of fatal drug overdose. This placebo-controlled, double-blind study examined the pharmacokinetic, physiologic, and behavioral effects of dual cocaine and ethanol administration in humans (n = 6). Cocaethylene was found in the plasma only after administration of both cocaine and ethanol, and appeared to be eliminated more slowly than cocaine. Plasma cocaine concentrations were significantly higher during cocaine/ethanol administration. Euphorigenic effects were both enhanced and prolonged, and heart rate was significantly increased, following cocaine/ethanol administration as compared to administration of cocaine or ethanol alone.

Serotonergic dysfunction in depression associated with Parkinson's disease.

A 55-year-old man presented with a 5-year history of Parkinson's disease and a 6-month history of major depression. The patient's depressive symptoms responded to treatment with fluvoxamine, a selective and potent serotonin reuptake inhibitor. Tryptophan depletion testing, which acutely lowers central serotonin levels, caused a brief exacerbation of the depressive illness, which resolved upon tryptophan repletion. Serotonergic dysfunction may be an etiologic factor in depression that occurs in Parkinson's disease.