Comparative abuse liability of intravenously administered remifentanil and fentanyl.

Remifentanil is a short-acting, esterase-metabolized opioid analgesic. This study compared the abuse liability of remifentanil with that of fentanyl and placebo in a randomized, double-blind, crossover study. Twelve recreational users of opioids received increasing doses of remifentanil (0.6, 1.2, 1.8, 2.4, and 3.0 microg/kg), fentanyl (0.4, 0.8, 1.3, 2.0, 3.0, and 4.5 microg/kg) and placebo via an intravenous infusion pump. Subjective measures (Cole/Addiction Research Center Inventory [ARCI] scales and visual analog scale [VAS] items such as "High" and "Good Effects") and physiologic variables (blood pressure, O2 saturation, pupil diameter) were recorded. For each measure, the differences from baseline were reduced to an area under the response curve (AUC) and a peak, and each subject's response to the maximum tolerable dose for each of the two active drug classes and mean response to several placebo infusions were entered into a 12 x 3 analysis of variance. All differences in drug versus placebo effects were significant. Although a majority of the peak effects that were measurable within 4 minutes after drug infusion reflected greater remifentanil effects, only one, High VAS, was statistically significant. In contrast, observations that could only be made > or = 5 minutes after drug infusion predominantly indicated significantly greater fentanyl peak effects, including High VAS, Liking VAS, Good Effects VAS, and Cole/ARCI Abuse Potential. Fentanyl AUCs were generally significantly larger than the corresponding remifentanil AUCs. A drug abuser seeking longer-lasting drug effects might select fentanyl over remifentanil, but these data do not completely rule out remifentanil abuse by some individuals with access to both the drug and the infusion equipment or by those who prefer briefer, repeated effects.

Efficacy of dexfenfluramine in the treatment of alcohol dependence.

BACKGROUND: A substantial body of evidence supports a role for serotonin in modulating alcohol intake, which suggests that this neurotransmitter represents a promising target for pharmacotherapy development for alcohol use disorders. Dexfenfluramine. a serotonin releaser and reuptake inhibitor, decreases alcohol self-administration by rats. Its greater potency and several mechanisms of action suggest it should be more effective in treating alcohol dependence than drugs that only inhibit serotonin reuptake. METHODS: We conducted an 11 week, randomized, double-blind trial that compared oral placebo and dexfenfluramine 7.5, 15, 22.5, and 30 mg bid in 136 alcohol-dependent patients. A brief behavioral intervention was offered concurrently. RESULTS: The majority of subjects were male (72%), and the age of the group was 44 +/- 1 years (mean +/- SD). Both placebo- and drug-treated groups significantly reduced alcohol consumption compared with baseline (a 55% decrease in mean drinks per day; p < 0.01), but there were no significant differences between drug and placebo groups or dose effects for most outcome measures. CONCLUSIONS: Our results with dexfenfluramine are further evidence that serotonergic medications on their own do not significantly reduce alcohol consumption in alcohol-dependent individuals. Combination pharmacotherapy with agents that act on different receptors or neurotransmitter systems (e.g., naltrexone plus dexfenfluramine) may be one way to enhance serotonergic effects on drinking behavior and should be considered in future medication development clinical trials.

Cytochrome P450 2D6 and treatment of codeine dependence.

Oral opioid analgesics such as codeine are used extensively worldwide and are frequently misused. Codeine is a substrate of CYP2D6, a genetically polymorphic P450 enzyme, and is metabolized to the more potent drug morphine. CYP2D6 activity can be inhibited by fluoxetine, and the inhibition of morphine formation may help individuals reduce their use of codeine. Fourteen long-term users of oral opiates (principally codeine) were assessed for an open-label pilot treatment study of fluoxetine 20 mg/day combined with a brief behavioral intervention and structured tapering of the opiate. Eight subjects entered and completed the 8-week treatment. Opiate use decreased by 30% to 100% of baseline use (p < 0.0001) in parallel with a decrease in CYP2D6 activity. Fluoxetine may have a role in the treatment of opiate dependence by decreasing opiate-reinforcing properties.

Polarographic and voltammetric behavior of selenious acid and its use in analysis.

Solution chemistry of Se(IV), in particular the acid-base properties, salt and complex formation, chemical reduction and reaction of Se(IV) with organic and inorganic sulfur compounds are briefly summarized. The electrochemical reduction of Se(IV) on dropping and stationary mercury electrodes is dealt with in some detail. The effects of antecedent acid-base equilibria and of consecutive reactions of the reduction product, Se(2-), adsorption of their products, and effects of added metal ions are discussed. The principles and applications of stripping analyses for determination of ultratraces of Se(IV) are summarized. The behavior on unreactive (Au, Pt, carbon) and reactive (Hg, Ag, Cu) electrodes are compared.

Differential pulse polarographic determination of selenium(IV) in whole blood using the catalytic hydrogen wave.

The selenium content in blood was determined using the hydrogen catalytic peak. This peak at -1.1 V was obtained in the presence of selenium and molybdenum at pH values of 1-4 in different buffers. For the determination of selenium, the Mo(VI) concentration has to be approximately 100-200 times higher than the selenium present. The linear domain range of selenium is 1x10(-6)-5x10(-9) M. The interference of zinc is eliminated by the addition of EDTA at pH 3.5 acetate buffer. The method was applied to 1.0 ml of digested blood, and 620+/-44 mug l(-1) Se and 7.15 mg l(-1) Zn could be determined with a 90% (n=6) confidence interval.

Attenuation of the euphoric effects of cocaine by the dopamine D1/D5 antagonist ecopipam (SCH 39166)

BACKGROUND: The subjective and reinforcing effects of cocaine in humans are associated with the enhancement of endogenous dopamine function in the mesolimbic system. This study examined the role of dopamine D1-like receptors in the behavioral and mood effects of cocaine by evaluating the effects of the selective D1/D5 antagonist ecopipam (SCH 39166) on subjective responses to intravenous cocaine in 11 subjects with cocaine dependence as defined by DSM-IV. METHODS: Subjects were pretreated in a randomized double-blind fashion with either placebo or 10 mg, 25 mg, or 100 mg of ecopipam orally on 4 separate occasions. Two hours later a single intravenous injection of 30 mg of cocaine was administered. Subjective and cardiovascular responses were measured and blood samples for pharmacokinetic evaluation were obtained prior to cocaine dosing and at various times after dosing. RESULTS: The euphoric (P = .004) and stimulating (P = .03) effects of cocaine were attenuated in a dose-dependent manner by ecopipam, while ratings of desire to take cocaine were diminished (P = .02). Ecopipam in combination with cocaine was safe and well tolerated. CONCLUSION: These data indicate a potentially important role for D1-like receptors in the acute mood-altering and rewarding effects of cocaine in humans.

Characteristics of dependent and nondependent regular users of codeine.

Although codeine is a widely used medication, the problems of codeine abuse and dependence have not been well-studied. This study characterized regular codeine users (using at least 3 days per week for 6 months, excluding those using codeine for the treatment of cancer pain) through a self-completed questionnaire. Recruitment through newspaper advertisements resulted in a total of 339 eligible questionnaires. Thirty-seven percent of subjects met DSM-IV criteria for codeine dependence. Dependent subjects (mean age, 40 +/- 10 years) were using an average of 179 (+/-171) mg of codeine per day. Codeine was predominantly used in the form of combination products with acetaminophen. Dependent subjects identified specific problems causally related to their codeine use such as depression (23%), anxiety (21%), and gastrointestinal disturbances (13%). The dependent subjects reported problems with other drugs more than did nondependent users (alcohol, 57% vs. 26%; cannabis, 23% vs. 5%; sedative/hypnotics, 33% vs. 12%; and heroin, 11% vs. 2%, respectively). Most were taking codeine primarily for a chronic pain problem (81%), although the dependent subjects currently found codeine less effective for treating pain than did the nondependent subjects and were more likely to use codeine for pleasurable effects, to relax, or to prevent withdrawal symptoms. This study showed that dependence is associated with the regular use of codeine. Pain is a key issue with these users; however, they are probably not receiving optimal treatment. There is a need to identify individuals experiencing problems with their codeine use and to develop optimal prevention and treatment strategies.

Long-term codeine use is associated with depressive symptoms.

A community survey was conducted among long-term (>6 months) users of codeine-containing products to characterize chronic use of these extensively consumed medications. Respondents recruited through newspaper advertisements completed a mailed questionnaire. Three hundred thirty-nine completed questionnaires were obtained, yielding a response rate of 70%. Codeine dependence/abuse as defined by DSM-IV criteria was present in 41% of the respondents. Two thirds of the subjects had sought help for mental health problems, most often depression (70%). Scores on the Symptom Checklist-90 subscales were modestly elevated, particularly on the Depression subscale (1.2 +/- 0.9). Long-term codeine use is strongly associated with dependence. Depression and depressive symptoms are common. These data suggest that dysphoric mood states may be significant in maintaining long-term codeine use.

A new selenite selective membrane electrode and its application.

A new membrane ion selective electrode sensitive to selenite ion has been developed. The electrode consisted of 1,2-phenylenediamine selen complex PIS (piaselenol) as the active material, PVC or SR (silicon rubber) as membrane matrix and DBF (dibutylphtalate) as plasticizer. This electrode showed linear response for selenite ion in the 10(-5)-10(-1)M concentration range. The slope of the linear portion was 21 mV/10-fold change in selenite concentration. The effect of membrane composition and membrane thickness on electrode response was studied and the electrode which contains 2% PIS, 49% PVC and 49% DBF was found to be the most sensitive one to selenite. The slope of the electrode did not change for 2 months and the pH change did not affect the response of the electrode in pH range of 3-9. The interferences of SO(4)(2-), SO(3)(2-), S(2-), HPO4(2-), CI(-), Br(-), and I(-) are investigated and while no interference was observed for SO(4)(2-), SO(3)(2-), S(2-) and I(-), a very small interference was observed for CI(-) and Br(-). The selenium present in anodic slime is determined using this electrode.

Preparation and properties of solid state selenite ion selective electrodes and their applications.

A new selenite ion selective electrode using solid salts of Ag(2)Se and Cu(2)S has been developed. Detailed information is provided concerning the composition, working pH and conditioning of the electrode. The change of potential with concentration is found to be linear in the range of 10(-5)-10(-2) M, the slope of the linear portion is 28 mV/10-fold change in selenite concentration. The effect of other ions on selenite response is evaluated and selenium content of anodic slime is determined.

Differential pulse polarographic determination of trace selenium(IV) and molybdenum(VI) using the catalytic hydrogen wave.

In the presence of selenium(IV) and molybdenum(VI) a new polarographic peak appears which corresponds to a hydrogen catalytic wave. By differential pulse polarography a single, sharp peak at about -1.1 V is obtained, allowing trace determination of selenium(IV) and molybdenum(VI) in the range 1x10(-6)-5.0x10(-9) M with a linear calibration and a detection limit of 1.5x10(-9) M. The optimum conditions are found to be 0.1 M KNO(3) and a pH of about 3.2 (Britton-Robinson buffer). There is no serious interference from some ions when present at 1.0-40 times that of molybdenum. At higher amounts of interfering ions the interference is eliminated by the addition of EDTA.

A controlled trial of ondansetron, a 5-HT3 antagonist, in benzodiazepine discontinuation.

Serotonin is implicated in the etiology of anxiety disorders and in the anxiolytic actions of benzodiazepines. Preclinical studies with 5-HT3 receptor antagonists, including ondansetron, show they have anxiolytic properties and that ondansetron suppresses withdrawal anxiety after abrupt discontinuation of chronic benzodiazepine treatment. We evaluated the efficacy of ondansetron as an adjunctive medication in the discontinuation of benzodiazepines in long-term users. One hundred eight patients who had used alprazolam or lorazepam regularly for > 3 months entered, and 97 completed a randomized double-blind discontinuation treatment program during which they received either ondansetron 2 mg twice daily or placebo and flexibly tapered their benzodiazepine over a 6-week period. There were no significant differences between the patients who had entered and completed treatment. Three weeks postmedication, 63% of the patients discontinued use of benzodiazepine. The percentage of reduction of benzodiazepine daily dosage at all time points in the treatment trial was similar for the ondansetron and placebo groups. Ondansetron had no significant effects on severity of withdrawal symptoms or levels of anxiety. High placebo response may have prevented detection of an ondansetron effect. At 1 year follow-up, 68% of patients reported that they stopped using benzodiazepine. Patient characteristics were more important than ondansetron in tapered benzodiazepine discontinuation.

Simultaneous determination of selenium and lead in whole blood samples by differential pulse polarography.

The polarographic reduction of lead in the presence of selenite gives rise to an additional peak corresponding to the reduction of lead (Pb) on adsorbed selenium (Se) on mercury at -0.33 V. The selenium and lead content can be determined using this peak by the addition of a known amount of one of these ions first and then the second ion. The linear domain range of lead is 5.0x10(-7)-2.0x10(-5) M and for selenium 5.0x10(-7)-1.0x10(-5) M. Using this method 4.90x10(-7) M Se(IV) and 1.47x10(-6) M Pb(II) in a synthetic sample could be determined with a relative error of +2.0% and 1.8%, respectively (n=4). A recovery test after acid digestion for a synthetic sample was 97% for selenium and 96.5% for lead. The method was applied to 1 ml of digested blood, and 328+/-23 mug l(-1) Se(IV) and 850+/-62 mug l(-1) Pb(II) could be determined with a 90% (n=5) confidence interval.

Inhibition of cytochrome P450 2D6 metabolism of hydrocodone to hydromorphone does not importantly affect abuse liability.

Enzymatic conversion of hydrocodone to hydromorphone is catalyzed by cytochrome P450 2D6, which is inactive in about 7% of Caucasians [poor metabolizers (PMs)] and can be inhibited by quinidine pretreatment in the remainder [extensive metabolizers (EMs)]. If hydromorphone, having a substantially higher mu-receptor affinity than hydrocodone, contributes importantly to the physiological and subjective effects of oral hydrocodone, then PMs should be less responsive to the same doses, and quinidine pretreatment should cause EMs to temporarily respond as PMs. Seventeen EMs and 8 PMs who previously responded positively to hydromorphone s.c. received placebo and hydrocodone (10 mg, 15 mg and 22.5 mg p.o.) and were retested with their favorite dose after placebo or quinidine (100 mg) pretreatment; physiological and subjective measures were collected at base line and four times after drug administration, and urine was collected for 8 hr. EMs and PMs were equally responsive to oral hydrocodone, and quinidine had no consistent effect on their responses, even though quinidine abolished the pre-existing metabolic differences in hydromorphone production, as measured in urine. These data suggest only a small role of hydromorphone in eliciting abuse-related responses to oral hydrocodone.

Clinical aspects of chronic use of alprazolam and lorazepam.

OBJECTIVE: The authors' goal was to determine the clinical characteristics of persistent users of alprazolam or lorazepam who wished to discontinue their medication. METHOD: Long-term users (daily use for more than 3 months) of alprazolam (N = 34) or lorazepam (N = 97) who entered an outpatient treatment program for discontinuation of benzodiazepines were carefully assessed. Detailed histories of benzodiazepine use were obtained; a structured interview was used to make psychiatric diagnoses based on DSM-III-R criteria. RESULTS: The majority of patients were using low therapeutic doses of medication (lorazepam: mean = 2.7 mg/day; alprazolam: mean = 1.2 mg/day) and had either maintained their initial daily dose over time or decreased it. Individuals tended to shift their use of medication from an as-prescribed to an as-needed pattern. Forty-seven percent of the patients were diagnosed with at least one current anxiety disorder, most commonly generalized anxiety. At least one diagnosable personality disorder was found in 45% of the patients, most commonly obsessive-compulsive personality disorder. Patterns of benzodiazepine use were influenced by age, gender, and past history of alcohol dependence. CONCLUSIONS: Long-term users of alprazolam/lorazepam seeking treatment for discontinuation had clinically important past and current psychiatric histories. They used a constant or decreasing dose of medication and made attempts to stop their use. Persistent use of alprazolam/lorazepam for therapeutic purposes did not represent abuse or addiction as the terms are usually understood. A substantial proportion of these patients may be receiving appropriate maintenance therapy for a chronic psychiatric condition.

Reconstitution of the water-oxidizing complex in manganese-depleted photosystem II complexes by using synthetic binuclear manganese complexes.

The efficiency of synthetic binuclear manganese complexes in reconstituting PS II electron flow and oxygen-evolution capacity was analyzed in PS II enriched preparations deprived of their manganese and of the extrinsic regulatory subunits. Measurements of the variable fluorescence induced by actinic illumination with continuous light led to the following results: (a) the synthetic binuclear complexes are more efficient than MnCl2 in establishing a PS II electron flow; (b) an almost complete restoration is achieved at concentrations of these complexes that correspond with an overall stoichiometry of two manganese per PS II; and (c) the electron flow restored by the binuclear manganese complexes closely resembles that of normal O2-evolving PS II preparations in its resistance to addition of 50 microM EDTA, while that supported by MnCl2 is practically completely suppressed at the same chelator concentration. The rate of O2 evolution was used as a measure of the capability to function as manganese source in reconstitution of the oxygen evolution capacity. It was found that (i) as in the case of PS II electron transport, the synthetic binuclear manganese complexes are significantly more efficient than MnCl2; (ii) with respect to the manganese concentration, the maximum effect is achieved with a mu-oxo bridged binuclear Mn(III) complex (symbolized by M-3) at concentrations corresponding to four manganese per PS II; and (iii) at all concentrations of binuclear manganese complex M-3 a significantly higher restoration of the O2 evolution rate is achieved if the reconstitution assay contains in addition the extrinsic regulatory 33 kDa protein (PS II-O protein).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical efficacy of the 5-HT3 antagonist ondansetron in alcohol abuse and dependence.

Medications that act on the serotonergic system have been found to be of benefit in the treatment of alcohol-dependent individuals. In a randomized, placebo-controlled study, the efficacy of 6 weeks of ondansetron, a 5-HT3 antagonist (0.25 mg bid or 2.0 mg bid), in the treatment of 71 nonseverely alcohol-dependent males was tested. The results showed reduction of drinking differences were steadily increasing toward the end of the treatment period approached significance at week 7 in the 0.25 mg group (p = 0.06). Twice as many patients in this group showed > or = 2 standard deviations decrease in drinking compared with the other groups. When patients drinking > 10 drinks/drinking day at baseline (n = 11) were excluded from the analysis, significant group differences were found at both treatment and follow-up, with the lower ondansetron dose producing the greatest reduction from baseline (i.e., 2.8 standard drinks; -35% compared with baseline and -21% compared with placebo; p < 0.02-0.001). Within this group, there was an almost 4-fold greater number of patients showing a clinically meaningful decrease in drinking. Lower baseline drinking and higher level of education were significant and strong predictors of drinking reduction during treatment. Ondansetron was very well tolerated; hence, further long-term studies with 5-HT3 antagonists alone or in combination with other treatment components may offer promise for treatment of alcoholism.

Binuclear manganese (III) complexes as electron donors in D1/D2/cytochrome b559 preparations isolated from spinach photosystem II membrane fragments.

The capability of different manganese complexes to act as PS II electron donors in D1/D2/cytochrome b559 complexes has been analyzed by measuring actinic light-induced absorption changes at 680 nm (650 nm) and 340 nm, reflecting the photoaccumulation of Pheophytin⁻ (Pheo⁻) and the reduction of NADP⁺, respectively. The data obtained revealed: a) the donor capacity of synthetic binuclear Mn (III)2complexes containing aromatic ligands significantly exceeds that for MnCl2 in both cases, i.e. Pheo⁻ photoaccumulation and NADP⁺ reduction; b) manganese complexes can serve as suitable electron donors for light-induced NADP⁺ reduction catalyzed by D1/D2/cytochrome b559 complexes and ferredoxin plus ferredoxin-NADP⁺ reductase under anaerobic conditions and c) the specific turnover rate of the system leading to NADP⁺ reduction is extremely small. The implications of these findings are briefly discussed.

Characteristics of long-term alprazolam users in the community.

The widespread use of benzodiazepines remains a source of concern to the medical profession and the general public, especially as newer compounds come on the market. Our goal was to characterize long-term alprazolam users in the community and to determine whether such use represented abuse or behavioural dependence. We conducted three community surveys to learn about the natural history of long-term alprazolam use. Current long-term alprazolam users (those using the drug for 3 months or longer) were recruited on three separate occasions 1 year apart by identical newspaper advertisements in the metropolitan Toronto area. All respondents were mailed a questionnaire with a stamped, addressed return envelope. Our data from 312 respondents show that: (1) the majority of patients have a substantial history of prior medication use for symptom control (65%), (2) dose escalation is not a characteristic of long-term use, (3) patients change their initial pattern of regular use to one of symptom control only when required, (4) most physicians do not discuss discontinuation of the drug with their patients, (5) patients frequently try to stop their drug use (with a median of 2 attempts) and often report symptoms upon discontinuation, and (6) patients perceive a need for medication use and indicate that alprazolam is effective (75%). We conclude that some patients persistently use alprazolam but that this use does not represent abuse or behavioral dependence.

Comparative drug effects and abuse liability of lorazepam, buspirone, and secobarbital in nondependent subjects.

The pharmacologic effects of lorazepam (2 mg), buspirone (20 mg, 10 mg), secobarbital (100 mg), and placebo were compared in 15 male, experienced, intermittent nontherapeutic drug users. All drugs produced a "drug effect," however, buspirone 20 mg was significantly less liked than were lorazepam, secobarbital, or buspirone 10 mg (p less than .05) but not placebo. Lorazepam was liked better than were other drugs only at 1 hour and only compared with buspirone 20 and placebo. Compared with other drugs, lorazepam drug effects were greater and resulted in more prolonged impairment of a motor tracking task, standing steadiness, and memory. Buspirone 20 mg significantly impaired memory at 1 hour compared with placebo. Subjects were more likely to identify buspirone as unfamiliar. Because buspirone 20 mg was less liked than were other drugs, dose escalation as part of drug abuse is not likely to occur. Lorazepam also was not particularly liked and was not different from placebo on most subjective abuse-relevant measures.