Effect of active metabolites of chlordiazepoxide and diazepam, alone or in combination with alcohol, on psychomotor skills related to driving

The interaction of the main metabolites of diazepam and chlordiazepoxide with alcohol was measured in two double-blind crossover subacute experiments on 40 healthy young volunteers. The drugs were administered for 2 weeks each. The variables measured were choice reaction time and accuracy, eye-hand coordination, divided attention, flicker fusion, proprioception, and nystagmus. ChL, MO and O significantly enhanced the alcohol-induced impairment of psychomotor skills whereas DMD did so only exceptionally on some subjects in the choice reaction test. It is concluded that the diazepam-alcohol interaction on psychomotor skills is mainly due to the parent compound. No correlations between the serum levels of the agents and the changes of performance were found.

Two weeks' treatment with chlorpromazine, thioridazine, sulpiride, or bromazepam: actions and interactions with alcohol on psychomotor skills related to driving

Subacute effects of C, T, S, or B, alone or in combination with A, were tested against P in two double-blind crossover trials with 37 healthy students. The drugs were given in capsules t.i.d. for 2 weeks each and the psychomotor performance (choice reaction, coordination, attention) was measured on the 7th and 14th days of treatment. At each session the subjects swallowed a capsule together with 0.5 g/kg of A or P drink, and the measurements were done, 30, 90, and 150 min thereafter. T alone did not differ from placebo in the doses used (10 mg t.i.d. for 7 days and 20 mg t.i.d. for the next 7 days). After C (dosing as above) and S (50 mg t.i.d.) both reactive and coordinative skills were slightly impaired. B (6 mg t.i.d.) clearly impaired both reactive skills and attention. T + A had no major combined effect on skills while C interacted with A resulting in impaired reactive and coordinative skills. After C + A the subjects were unable of compensating their coordination mistakes by slow driving. The interaction of S with A was mild, whereas B + A strongly impaired coordination and divided attention. No alterations were recorded in flicker fusion after any treatment.

Acute effect of antipyretic analgesics, alone or in combination with alcohol, on human psychomotor skills related to driving

1 The effect of acetylsalicylic acid (1 g), indomethacin (50 mg), and phenylbutazone (200 mg) on psychomotor skills was examined double blind on 180 volunteer students. Ninety students received ethyl alcohol (0.5 g/kg) and 90 subjects an equal volume of placebo drink in combination with the drugs. 2 Psychomotor skills were measured with a choice reaction test, two co-ordination tests, and a divided attention test, having correlation with traffic behaviour. The subjects assessed their feelings of performance by means of a rating scale. The tests were done 30, 90 and 150 min after the administration of the agents. 3 Acetylsalicylic acid proved inactive whereas both indomethacin and phenylbutazone impaired eye-hand co-ordination and divided attention. Acetylsalicylic acid did not interact with alcohol to a measurable extent whereas indomethacin in combination with alcohol proved less harmful than without it. The deleterious effects of phenylbutazone and alcohol were additive. 4 An impairment of psychomotor skills related to driving by indomethacin and phenylbutazone should be considered when prescribing these drugs to active out-patients.

Interaction of clonidine and beta-blockers

On the hypothesis that non-selective beta-blockers can antagonize or reverse the antihypertensive effect of clonidine (C), 12 hypertensive outpatients were treated with C alone and in combination with propranolol (P), atenolol (A) and prazosin (Pz). C alone (0.11 or 0.22 mg b.i.d.) or in combination with P (80 mg b.i.d.) did not provide normotension. Changing P to A (50 mg b.i.d.) reduced supine systolic and diastolic pressures, which now were significantly lower (p less than 0.01) than during C alone. Changing A to P again resulted in elevated pressures. Pz (1 mg t.i.d.) added to the C+P regimen lowered supine blood pressures to the levels otherwise recorded during C+A. C dose-dependently contracted rabbit aortic spiral in vitro, reaching about 50% of maximum responses to noradrenaline. Pz abolished this response. P (0.1--10 micrograms/ml) but not A somewhat enhanced responses to high doses of C. Sotalol rather antagonized C contractions. We conclude that A but not P enhances the antihypertensive action of C. No hypertensive interaction was observed.

Polymorphic acetylator phenotype and systemic lupus erythematosus

Out of 69 patients with spontaneous systemic lupus erythematosus (SLE), phenotyped for polymorphic acetylation with sulphadimidine, 52 (75%) were slow acetylators. In the subgroup of SLE patients with chronic biologically false positive seroreactions for syphilis the percentage of slow acetylators was even higher, 88%. In the majority of the slow acetylators the disease had started later and had followed a milder course than in rapid acetylators. Cutaneous reactions suspected to be drug-induced were seen in 19 (17 slow acetylators) during an observation period of 3--7 years. The reactions were mostly of exanthematous or urticarial type but also fixed type of eruption was seen. Provocation tests with the suspected drug were performed in 14 patients. In 5 cases it could be demonstrated that the eruption was caused by the drug. The predominance of slow acetylators among our patients with spontaneous SLE was the same as has been observed in drug-induced SLE. This suggests a similar genetic background.

Midazolam 12 mg is moderately counteracted by 250 mg caffeine in man

OBJECTIVE

Caffeine (Caf) counteracts various effects of benzodiazepines (BZDs). Since the effects of zolpidem, a short-acting atypical GABA(A)-BZD agonist, were not antagonized by Caf, we studied an interaction between Caf and midazolam (Mid) in healthy volunteers.

SUBJECTS, MATERIALS AND METHODS

In Study 1, 108 healthy students divided to 6 parallel groups were given Mid 12 mg (capsule) and Caf 125 and 250 mg (in decaffeinated coffee), alone and in combinations in the double-blind placebo-controlled manner. Objective and subjective tests were done before and at 45 and 90 min after intake. Ranked delta-values (changes from baseline) were analyzed by one-way contrast ANOVA and Scheffe's tests. In Study 2, six healthy subjects took Mid 15 mg (tablet) with and without Caf 300 mg. The dynamic effects were analyzed as in Study 1 and the plasma concentrations were assayed.

RESULTS

In Study 1, learn effects after placebo (ad + 15%) were seen for letter cancellation and digit symbol substitution tests. Midazolam alone significantly (p < 0.05 vs. delta-placebo) reduced letter cancellation and digit symbol substitution, lowered flicker fusion, impaired digit learning and caused subjective calmness on VAS. Caffeine alone did not differ from placebo objectively, yet improved quick-wittedness and contentedness on VAS. In the combinations, Mid + Caf 125 mg differed from placebo objectively as Mid alone, whereas Mid + Caf 250 mg did not. Mid + Caf 250 mg differed from Mid on digit substitution, but did not differ from Mid+Caf 150 mg in impairing memory and causing subjective sedation. In Study 2, Mid 15 mg caused sedation and Caf 300 mg increased plasma Mid at 45 min. Mid + Caf did not differ from Mid alone objectively, but did so subjectively on VAS (p > 0.05).

CONCLUSION

In conclusion, in a parallel group study, sedative effects of Mid 12 mg were only moderately antagonized by Caf 250 mg but not by Caf 125 mg. In a cross-over study, a weak interaction was found subjectively but not in objective measures.

Driving under light and dark conditions: effects of alcohol and diazepam in young and older subjects

OBJECTIVES

Driving at night time increases accident risk due to visual conditions, fatigue and impaired performance. In addition, the use of alcohol and benzodiazepines may enhance the risks related to night-time driving. We studied these aspects of traffic safety in a simulated driving test with young and older drivers.

METHODS

In a double-blind, crossover, placebo-controlled study, nine young subjects, aged 22-24 years, performed simulated driving in both 'light' and 'dark' conditions, before and 1.5 h and 4 h after 0.8 g x kg(-1) ethanol (EOH) or 15 mg diazepam (DZ). Further, nine older subjects, aged 55-77 years, were similarly tested, but their EOH dose was 0.7 g x kg(-1) and the DZ dose was 10 mg. The tests were vigilance assessment on visual analogue scales (VAS), simulated driving under light and dark conditions for 6 min each and digit symbol substitution (DSS).

RESULTS

In the young subjects, both EOH and DZ similarly impaired DSS, with DZ causing more subjective drowsiness, clumsiness, mental slowness and poor overall performance than EOH. During simulated driving, both EOH and DZ impaired simple and complex tracking (EOH > DZ) and prolonged reaction times (EOH = DZ). Impairment of performance was practically identical under light and dark conditions. In the older subjects, objective performance on DSS was poorer (-30%) than that of the young ones, and subjective impairment was marginal. During simulated driving, the baseline levels of variables in older subjects showed definite impairment (errors +100% to +500%) when compared with young subjects. Active drugs impaired several variables (EOH > DZ), but the statistical significances were fewer than in young subjects. Increase in reaction errors reached statistical significance, especially while driving in the dark. Otherwise the driving results in light and dark were not notably different.

CONCLUSION

Young subjects drew good baselines but were sensitive to EOH and DZ, whilst the older subjects showed poor baselines but were less sensitive to EOH and DZ. Although the baseline driving and responses to treatments were different in young and older subjects, their driving and psychomotor impairment were unaffected by light conditions.

Variations among non-sedating antihistamines: are there real differences?

Most of the modern non-sedating H1 receptor antagonists (antihistamines) penetrate the brain poorly, allowing the use of doses large enough to counteract allergic processes in peripheral tissues without important central effects. The antihistamines reviewed here are acrivastine, astemizole, cetirizine, ebastine, fexofenadine, loratadine, mizolastine, and terfenadine. However, these drugs are not entirely free from central effects, and there are at least quantitative differences between them. Although psychomotor and sleep studies in healthy subjects in the laboratory may predict that an antihistamine does not cause drowsiness, the safety margin can be narrow enough to cause a central sedating effect during actual treatment. This might result from a patient's individual sensitivity, disease-induced sedation, or drug dosages that are for various reasons relatively or absolutely larger (patient's weight, poor response, reduced drug clearance, interactions). Mild to even moderate sedation is not necessarily a major nuisance, particularly if stimulants need be added to the regimen (e.g. in perennial rhinitis). Furthermore, patients can adjust doses themselves if needed. Sedating antihistamines are not needed for long-term itching, because glucocorticoids are indicated and more effective. It is wise to restrict or avoid using antihistamines (astemizole, terfenadine) that can cause cardiac dysrhythmias, because even severe cardiotoxicity can occur in certain pharmacokinetic drug-drug interactions. Histamine H1 receptor antagonists (antihistamines) are used in the treatment of allergic disorders. The therapeutic effects of most of the older antihistamines were associated with sedating effects on the central nervous system (CNS) and antimuscarinic effects causing dry mouth and blurred vision. Non-specific "quinidine-like" or local anaesthetic actions often led to cardiotoxicity in animals and man. Although such adverse effects varied from drug to drug, there was some degree of sedation with all old antihistamines. Non-sedating antihistamines have become available during the past 15 years. Some of them also have antiserotonin or other actions that oppose allergic inflammation, and they are not entirely free from sedative effects either. In small to moderate "clinical" concentrations they are competitive H1 receptor antagonists, although large concentrations of some of them exert non-competitive blockade. Daytime drowsiness and weakness are seldom really important, and they restrict patients' activities less than the old antihistamines. Some new antihistamines share with old antihistamines quinidine-like effects on the cardiac conducting tissues, and clinically significant interactions have raised the question of drug safety. This prodysrhythmic effect has also been briefly mentioned in comparisons of non-sedative H1 antihistamines.

Zolpidem 10 mg given at daytime is not antagonized by 300 mg caffeine in man

OBJECTIVE

Caffeine counteracts various effects of traditional benzodiazepines (BZDs). As zolpidem, a short-acting hypnotic, is an atypical GABAA-BZD agonist, we investigated when caffeine would counteract the effects of zolpidem as well.

METHODS

In daytime study I, zolpidem 10 mg (capsule) and caffeine 150 or 300 mg (in decaffeinated coffee) were given, alone and in combinations, to parallel groups (n = 15-17) of healthy students in double-blind and placebo-controlled manner. Objective and subjective tests were done before and 45 min and 90 min after intake. Ranked delta values (changes from baseline) were analysed by one-way contrast ANOVA and Scheffe's tests. In daytime study II, four healthy subjects took zolpidem 10 mg alone, and together with blinded caffeine 250 mg or (at -45 min) erythromycin 750 mg. Objective and subjective effects were measured and plasma zolpidem concentrations assayed at baseline and 45 min and 90 min after zolpidem intake.

RESULTS

In study I, practice effects after placebo (ad + 30%) were seen for letter cancellation and digit symbol substitution but not for flicker fusion tests. Zolpidem alone significantly impaired (P < 0.05 vs delta placebo) letter cancellation and digit symbol substitution at 45 min and 90 min, lowered the flicker fusion threshold at 45 min, and caused subjective drowsiness, mental slowness, clumsiness and feeling of poor performance. Caffeine alone showed a non-significant trend to improve objective performance. The combined effects of zolpidem and either dose of caffeine matched those measured after zolpidem alone. Zolpidem + caffeine 300 mg was not stronger than zolpidem + caffeine 150 mg in impairing immediate memory and causing subjective sedation. In study II, zolpidem caused objective and subjective sedation; neither caffeine nor erythromycin modulated the effects of zolpidem or plasma zolpidem concentrations.

CONCLUSION

The sedative effects of 10 mg of zolpidem are not antagonized by 150-300 mg of caffeine in pharmacodynamic or pharmacokinetic terms.

Effects of alcohol, zolpidem, and some other sedatives and hypnotics on human performance and memory

Zolpidem (Zol), an omega1-agonist, acts via GABA(A) receptors but may differ qualitatively from diazepam (Dz) and other benzodiazepines (BZDs). We conducted a placebo-controlled, randomized, double-blind, and crossover study to compare the psychomotor and cognitive effects of 15 mg Zol with those of 15 mg Dz, 30 mg oxazepam (Ox), 7.5 mg zopiclone (Zop), and ethanol (EOH; 0.65 + 0.35 g x kg(-1)) given to 12 subjects at 1-week intervals. Psychomotor tests (symbol digit substitution, simulated driving, flicker fusion, body sway) were done before and 1, 3.5, and 5 h after intake; immediate and delayed memory were measured between 1.5 and 3.5 h. The plasma concentrations of drugs were measured by gas chromatography and by radioreceptor assay (RRA). The mean values of EOH in blood at 1.5, 4, and 5.5 h were 0.82, 0.88, and 0.6 g x l(-1), and the mean values of RRA-assayed plasma Dz were 470, 330, and 210 microg x l(-1), respectively. The corresponding values of other hypnosedatives, in Dz equivalents (microg x l(-1)), were 550, 750, and 330 for Ox; 350, 270, and 70 for Zol; and 160, 210, and 70 for Zop. The standard RRA graph for Zol was significantly flatter than those for other hypnotics. Zol impaired coordinative, reactive, and cognitive skills at 1 and 3.5 h more clearly than the other agents did, the most sensitive performance (tracking) still being impaired by Zol at 5 h. Dz and Zop were less active than Zol objectively; subjective sedation after Dz and Zol was stronger than after Zop. Compared to placebo, all active agents tended to impair learning and memory, their decremental effects, in declining order, being Zol, Dz > EOH, Ox > Zop. During the delay, Dz and Zol caused similar losses of material that had been learned. When separating "true" delayed memory from immediate memory (attention important), Dz and Zol had equieffects on delayed memory and were more detrimental than Zop. When contrasting that against the impaired psychomotor performances, it is possible that 15 mg Zol impairs memory relatively less than 15 mg Dz does.

Effects of alcohol and hypnosedative drugs on digit-symbol substitution: comparison of two different computerized tests

Computerized symbol-digit substitution tests (SDSTs) and 'yes/no' digit-symbol substitution tests (YNDSTs), together with a digit-digit copying test (DDCT) were compared in a double-blind crossover study for hypnosedative and alcohol effects in 12 young healthy subjects. The tests were carried out before and 1, 3.5 and 5 h after intake of 15 mg diazepam, 30 mg oxazepam, 7.5 mg zopiclone, 15 mg zolpidem or 0.65+0.35 g/kg ethanol, these impaired performance by varying extents. The drug-induced decrements were similar in the YNDSTs and SDSTs; the errors were subject-related and increased with alcohol intake in the YNDSTs but not in the SDSTs. Pooled baseline values in YNDSTs correlated well (Pearson) with those in the SDSTs. The SDSTs also correlated well with the DDCTs. The same correlations were seen when comparing absolute performances after ethanol and hypnosedatives. When using the delta-values (changes from baseline), the correlation between YNDSTs and SDSTs was high after placebo but low after alcohol and hypnosedatives. When using ANCOVA to measure the responses to drugs (delta-drug-delta-placebo), the correlation between YNDSTs and SDSTs was fairly significant after most but not all active drugs. Subjective visual analogue variables did not correlate with objective performances. By comparing absolute performances with hypnosedatives we conclude that YNDSTs and SDSTs are similar, with the delta-values indicating differences between them.

GABA(A)-receptor subtypes: clinical efficacy and selectivity of benzodiazepine site ligands

The main inhibitory neurotransmitter receptor of the brain, the gamma-aminobutyric acid type A receptor (GABA[A]), mediates the actions of several classes of clinically important drugs, such as benzodiazepines, barbiturates and general anaesthetics. This review summarizes the current knowledge on how classical benzodiazepines and novel nonbenzodiazepine compounds act on the benzodiazepine site of GABA(A) receptors and on their clinical pharmacology related to anxiolytic, sedative, hypnotic and cognitive effects or side-effects. Partial agonism, receptor subtype selectivity and novel binding sites are discussed as possible strategies to develop new drugs with fewer adverse effects than are seen in the clinical use of benzodiazepines.

Single oral doses of amisulpride do not enhance the effects of alcohol on the performance and memory of healthy subjects

OBJECTIVES

Amisulpride is a benzamide antipsychotic that binds selectively to dopamine D2- and D3-receptors, preferentially in limbic and hippocampal structures. Since other substituted benzamides have a limited or negligible interaction with alcohol on human performance, amisulpride was studied for this potential.

METHODS

In a randomised double-blind crossover study, 18 young, non-smoking men took single oral doses of placebo and amisulpride 50 mg and 200 mg, without and with ethanol (0.8 g. kg-1) taken 30 min later. Objective performance tests and self-ratings were done at baseline and 1.5, 3.5 and 6.5 h after drug intake. Memory (immediate and delayed recall) was tested 2 h after dosing. Breath ethanol and the plasma concentrations of amisulpride and prolactin were measured. Three-way ANOVA + Newman-Keul tests were used for statistical analyses; interactions were confirmed by factorial contrast ANOVA.

RESULTS

Mean blood ethanol was 0.94, 0.62 and 0.26 g.1(-1) at the three test times. It produced significant impairment in all performance tests (symbol digit substitution, simulated driving, body sway, flicker fusion, tapping, nystagmus), reduced both immediate and delayed recall in memory tests, and caused subjective clumsiness, muzziness and mental slowness, mainly between 1.5 to 4.5 h after dosing. Amisulpride, 50 and 200 mg elevated plasma prolactin but had minimal or no effect on performance, attention and memory. The decreases in immediate free recall after the 50 mg dose and in delayed free recall after the 200 mg dose were slight. Amisulpride neither modified blood ethanol concentrations nor enhanced the detrimental effect of ethanol on skilled and cognitive performance; it slightly antagonised ethanol in the digit copying test. Ethanol did not modify the effect of amisulpride on plasma prolactin, and the plasma concentrations of amisulpride were little changed by ethanol.

CONCLUSIONS

Amisulpride in single oral doses of 50 and 200 mg did not interact significantly with the effects of high, moderate or low concentrations of ethanol on human skilled and cognitive performance. The drugs did interact pharmacokinetically.

Grapefruit juice does not enhance the effects of midazolam and triazolam in man

OBJECTIVES

Since grapefruit juice (Gra) inhibits hepatic P450 (CYP3A4), we studied its potential to enhance the effects of midazolam (Mid) and triazolam (Trz), which are metabolized by the CYP3A4 isoenzyme.

METHODS

In Study I parallel groups of healthy students were given orally Mid 10 mg with water or grapefruit juice (GraMid), two placebo groups receiving water or Gra. The effects of Mid were measured by psychomotor tests and by self-rating on visual analogue scales before and 30 and 90 min after intake. Study II was similar, but the post-treatment tests were at 45 and 90 min, and the active drugs used were 0.250 mg Trz, GraTrz, and Mid 10 mg. In the crossover Study III, 6 subjects took Mid 10 mg alone and with Gra (GraMid) and 750 mg erythromycin (EryMid). Performance tests were made and blood was sampled before and 30, 60 and 90 min after intake. Midazolam and its active metabolite alpha-OH-midazolam were assayed by gas chromatography (GC) and radioreceptor assay (RRA).

RESULTS

In Study I, both Mid and GraMid impaired digit symbol substitution (DSS), letter cancellation (LC) and flicker fusion (CFF) at 90 min. GraMid had more effect (P < 0.05) than Mid on the DSS performance. Mid caused drowsiness at 30 and 90 min. Both Mid and GraMid caused clumsiness and a feeling of impaired performance at 90 min. In Study II, the active drugs impaired objective test performances (DSS, LC, CFF) at 90 min, without having a clear subjective effect. In Study III, Mid, EryMid and GraMid impaired performance in the DSS, LC and CFF tests. EryMid proved stronger than Mid and GraMid on DSS and LC tests at 30 min. Mean values of plasma midazolam (and alpha-OH-midazolam) at 30, 60, 90 and 120 min after Mid 10 mg were 68(19), 61(19), 43(14) and 42(12) micrograms.l-1. The corresponding values after EryMid were 164(14), 137(13), 104(10) and 89(10) micrograms.l-1, and after GraMid 60(12), 69(16), 61(15) and 57 (14) micrograms.l-1.

CONCLUSIONS

The grapefruit juice used did have any particular interaction with oral doses of 10 mg midazolam and 0.25 mg triazolam in healthy young subjects.

150 mg fluconazole does not substantially increase the effects of 10 mg midazolam or the plasma midazolam concentrations in healthy subjects

Fluconazole, an azole antifungal agent, moderately inhibits the CYP3A-mediated metabolism of midazolam in vitro. We therefore studied whether such an interaction takes place in vivo following oral administration of these drugs, given as relevant double blinded doses in capsule form. In study I parallel groups of healthy subjects received oral midazolam 10 mg (MID 10) or 15 mg (MID 15), placebo, or MID 10 mg + 150 mg fluconazole (FLU) given 2 h earlier. Objective and subjective performance tests were made before, and 30 and 90 min after the intake of midazolam. MID 10 and MID 15 moderately impaired performance on digit symbol substitution, letter cancellation and flicker fusion tests, and visual analogue scales revealed mild sedation. FLU + MID 10 had similar or slightly stronger effects than MID 10; it differed from MID 10 in that it lowered the flicker fusion threshold and produced subjective slowness and overall impairment. In study II 5 subjects received MID 10 after placebo, after FLU, and after 750 mg erythromycin (ERY) at 1-week intervals, following a crossover and double-blinded study design. Blood was sampled before MID intake and 30, 60 and 90 min after it, and performance was measured. FLU and ERY increased the effect of MID on flicker fusion and letter cancellation performances, and increased the HPLC-assayed plasma midazolam (ERY + 100%, FLU + 50%) in comparison to that measured after MID ingested alone. When the concentrations of midazolam together with its active metabolite alpha-OH-midazolam were assayed by radioreceptor technique the increases caused by ERY and FLU were less and compatible with the pharmacodynamic data.(ABSTRACT TRUNCATED AT 250 WORDS)

Lorazepam and diazepam differently impair divided attention

Effects of ethanol (EtOH, 0.65 + 0.35 g.kg-1), diazepam (DZ, 15 and 30 mg), lorazepam (LZ, 2 mg) on divided attention were measured in two placebo-controlled crossover studies with healthy young subjects. The test comprised four parallel computer screens with a ball moving along a circular obstacle course on each screen at different rates. When the ball entered an obstacle on any screen, the subject had to press the respective button. The obstacles varied in numbers and shapes, and randomly changed their location every 10 s. Concomitant aural stimuli were responded to by pushing the foot pedals. The primary visual variables were the absolute and percent numbers of correct responses on each screen. Concentrated attention was measured with a symbol digit substitution (SDST) and digit copying (DDCT) tests, for 3 min each. In Study I, with 12 subjects, the tests (4 min) were made before the treatment (placebo, EtOH, DZ) and 1, 3, and 6 h after intake. EtOH impaired attention on the lateral but not on medial screens, with and without aural stimuli, the "special" obstacles of deviating shape being the most sensitive targets to EtOH effects. DZ 15 mg did not modify divided attention whereas it impaired SDST performance and was subjectively slightly more potent than EtOH on visual analog scales. DZ 30 mg impaired attention on the lateral screens, with and without aural stimuli, but without preference to "special" obstacles. It also reduced responses to aural stimuli, strongly impaired SDST and DDCT, and caused subjective sedation. In Study II, with 9 subjects, the test run without aural stimuli was easier but lasted for 15 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Azithromycin does not alter the effects of oral midazolam on human performance

Since macrolide antibiotics inhibit the oxidative hepatic metabolism of various drugs, including midazolam, the present double blind studies were conducted to find out if azithromycin, a new macrolide of the azalide type, would inhibit the metabolism of midazolam and enhance the effects of midazolam on human performance. In Study I, 64 healthy medical students, divided in four parallel groups received placebo, midazolam (10 mg or 15 mg), and midazolam 10 mg combined with azithromycin (500 mg + 250 mg). In Study II, three males received oral midazolam 10 mg in combination with placebo, azithromycin or erythromycin 750 mg (as a positive control) in a cross-over trial. Objective and subjective tests were done before the intake of midazolam and 30 and 90 min after it, and venous blood was sampled for the assay of midazolam. In the placebo group in Study I, the mean numbers of letters cancelled (LC) at baseline, 30 min and 90 min were 21, 20 and 20, respectively, and the corresponding mean numbers of correct digit symbol substitutions (DSS) were 126, 137 and 140, indicating a practice effect. Midazolam 10 mg impaired these performances (21, 13 and 12 for LC, and 127, 113 and 111 for DSS). Either dose of midazolam produced clumsiness, mental slowness and poor subjective performance, midazolam 15 mg being slightly more active. The corresponding, scores in the azithromycin+midazolam group were 21, 16, 16 for LC, and 132, 121 and 119 for DSS, the only significant difference from placebo being the impairment of DSS at 90 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Suriclone enhances the actions of chlorpromazine on human psychomotor performance but not on memory or plasma prolactin in healthy subjects

Twelve healthy subjects received single oral doses of 0.4 mg suriclone (SU), 7.5 mg zopiclone (ZO) and placebo, alone and together with 50 mg chlorpromazine (CP), double blind and crossover, in Latin square order, at one-week intervals. Performance tests administered before and 1.5, 3.5 and 6 h after drug intake included digit symbol substitution and simulated driving combined in a "Global test", flicker fusion frequency, body balance and memory and subjective assessments. Changes from baseline were examined statistically. Performance and memory data were analysed from only 11 subjects. Compared to placebo, SU minimally affected "global" performance, although it slowed reactions and tended to impair digit substitution. ZO impaired "global" performance at 1.5 h, affected performance in several separate tests, and produced subjective muzziness. CP did not impair "global" performance, although it did impair digit substitution and render the subjects drowsy, weak and dreamy. The combinations SU + CP and ZO + CP definitely impaired "global" performance more than CP alone. This difference was also found in most objective tests but less so in the subjective tests. CP and its combinations produced similar increases in plasma prolactin. Active drugs and their combinations variably lowered blood pressure and increased heart rate, and one subject collapsed after CP. The treatments irregularly impaired spatial memory and learning acquisition. No pharmacokinetic interactions were seen in the plasma levels of suriclone, zopiclone and chlorpromazine. The impairment of performance after these combinations resembles that previously encountered after 2.5 mg lorazepam, or 15 mg diazepam + 100 mg remoxipride.

Pharmacokinetics of oxicam nonsteroidal anti-inflammatory agents

Oxicam nonsteroidal anti-inflammatory drugs (NSAIDs) are a group of structurally closely related substances with anti-inflammatory, analgesic and antipyretic activities. They have a weakly acidic character and are extensively bound to plasma proteins. Piroxicam, the most widely used oxicam, is well absorbed after oral administration. Peak plasma concentrations (Cmax) of the drug are reached within 2 to 4 hours. Piroxicam has a small volume of distribution and a low plasma clearance. It undergoes hepatic metabolism and only 5 to 10% is excreted unchanged in urine. The elimination half-life varies between 30 and 70 hours. Age of the patient and renal or hepatic dysfunction do not seem to have any major effect on the pharmacokinetics of piroxicam. The drug reduces the renal excretion of lithium to a clinically significant extent, but the clinical significance of piroxicam-aspirin (acetylsalicylic-acid) and piroxicam-acenocoumarol interaction has not been established. Ampiroxicam, droxicam and pivoxicam are prodrugs of piroxicam that have been synthesised to reduce piroxicam-related gastrointestinal irritation. All prodrugs are well absorbed, but Cmax values are reached later than those following administration of piroxicam. Tenoxicam is used in the management of rheumatic and inflammatory diseases. Mean Cmax values are achieved 2 hours postdose. Food reduces the rate but not the extent of absorption. The oral bioavailability of tenoxicam is 100% and rectal bioavailability is 80%. Like piroxicam, tenoxicam has a low volume of distribution and low plasma clearance. It is eliminated through hepatic metabolism. The mean elimination half-life is 60 to 75 hours. The pharmacokinetics of tenoxicam are independent of patient age, or concurrent liver or renal diseases. High doses of aspirin have been shown to increase the elimination of tenoxicam, but this has little clinical significance. Isoxicam was in widespread clinical use until its worldwide marketing was suspended because of fatal skin reactions. Isoxicam is completely absorbed, but Cmax values are not reached until 10 hours postdose. It has a low plasma clearance, approximately 5 ml/min (0.3 L/h), and low volume of distribution. The mean elimination half-life is 30 hours and does not appear to be affected by the age of the patient. Isoxicam potentiated the anticoagulant effect of warfarin, necessitating a 20% dosage reduction. Lornoxicam differs from other oxicam NSAIDs because it has a short elimination half-life of 3 to 4 hours. On the basis of limited data, some individuals seem to eliminate lornoxicam very slowly, suggesting the presence of polymorphic metabolism. The pharmacokinetics of cinnoxicam and sudoxicam have not been studied thoroughly.(ABSTRACT TRUNCATED AT 400 WORDS)

Ethanol antagonism by atipamezole on motor performance in mice

The interactions of an alpha 2-adrenoceptor antagonist, atipamezole, and an alpha 2-adrenoceptor agonist, dexmedetomidine, with ethanol were studied in male NIH Swiss mice. The mice were given (i.p.) atipamezole 0.1, 0.3, 1, 3 and 10 mg/kg and dexmedetomidine 0.01, 0.03, 0.1, 0.3, 1, 3 and 10 mg/kg; the ethanol doses were 1, 2 or 3 g/kg. Motor performance was measured by spontaneous locomotor activity and rotarod test. Dexmedetomidine impaired performance in both tests. The effect of dexmedetomidine peaked at the dose of 1 mg/kg. Three mg/kg of atipamezole abolished totally the effects of 0.3 mg/kg of dexmedetomidine and partially those of 1 mg/kg of dexmedetomidine. Atipamezole counteracted and dexmedetomidine enchanced ethanol effects in both tests. The interactions were not of pharmacokinetic origin since blood and brain ethanol and dexmedetomidine levels were unaltered at the time of testing. The results suggest that ethanol effects on motor performance in mice are mediated in part via central noradrenergic mechanisms, and blockade of alpha 2-adrenoceptors by atipamezole leads to considerable antagonism of these ethanol effects.

Effects of psychotropic drugs on digit substitution: comparison of the computerized symbol-digit substitution and traditional digit-symbol substitution tests

The digit-symbol substitution test (DSST), performed with paper and pencil or computerized, is widely used to reveal decrements in human attention and cognition. We programmed sets of adjustable tasks (digit-symbol, digit-digit, symbol-digit, symbol-symbol) into a microcomputer and compared the symbol-digit substitution (SDST) and the digit copying test (DDCT) with the traditional DSST in two placebo-controlled double-blind studies of psychotropic drugs with pre-trained young healthy subjects. Performances were measured before drug intake and several times after it; matched, different codes were used at consecutive tests. DSST and SDST substitutions remained at the baseline level after placebo, while the simple DDCT performance improved during the placebo session. The prolonged (3 min) test was not exhaustive because interim counts at 90 s predicted the final performance well. In Trial I, 15 mg diazepam orally reduced DSST and SDST functions in a similar way, but it also impaired simple copying in the DDCT, though to a lesser extent. Ebastine, an H(1)-antihistamine, proved inert alone and failed to increase the effects of diazepam on these variables. In Trial II, 7.5 mg zopiclone, 0.4 mg suriclone and 50 mg chlorpromazine, alone and in combinations, impaired the DSST performance in the manner expected. The drug effects were similar in the SDST, and somewhat less in the DDCT, while the substitution errors were subject related and not altered significantly by any treatment. The simple correlation matrices (Pearson, Spearman), confirmed by analysis of covariance, showed that the results of DSST correlated fairly well with those of SDST after zopiclone, chlorpromazine and their combination, but not after suriclone or its combination with chlorpromazine. The DDCT results correlated with those of the substitution tests when analysing pooled baseline values, but not when analysing the performances after drug intake. Subjective visual analogue variables correlated poorly or not at all with objective performances. Our results suggest that manual dexterity in these computerized tests might contribute significantly to the total impairment of performance in response to different drugs. The DSST and SDST matched each other fairly well in their sensitivity to drug effects, yet this similarity may depend on the drug used.

Oral single doses of erythromycin and roxithromycin may increase the effects of midazolam on human performance

Macrolide antibiotics are known to inhibit the metabolism of triazolam and midazolam in vitro and in vivo. To find out if significant interactions take place after single oral doses of these agents to man, 0.25 mg triazolam and 5, 10 and 15 mg of midazolam in capsule from were given with and without 750 mg erythromycin or 300 mg roxithromycin to parallel groups of healthy subjects in four placebo-controlled double-blind studies. Objective tests and subjective assessments were made before the intake of hypnotics and 30 and 90 min after it. In Study I, triazolam impaired letter cancellation, the combination triazolam+erythromycin impaired digit symbol substitution and letter cancellation, and triazolam+roxithromycin impaired digit symbol substitution, all at 90 min. In Study II, midazolam 5 mg and midazolam 10 mg proved quite inert but the combination midazolam 5 mg+erythromycin impaired digit symbol substitution. In Study III, both midazolam 10 mg and midazolam 15 mg impaired digit substitution and letter cancellation, the effects of 15 mg being more prominent. The strongest drug effects were found with midazolam 10 mg+erythromycin which differed from placebo and midazolam (10 mg and 15 mg) in several objective and subjective test variables. In Study IV, the combination midazolam 10 mg+roxithromycin impaired several objective and subjective variables but it was not stronger than midazolam 15 mg. These results were supported by the direct measurements of plasma midazolam in three subjects: erythromycin increased plasma midazolam more than roxithromycin and enhanced midazolam effects following the intake of midazolam 10 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

Diazepam effects on the performance of healthy subjects are not enhanced by treatment with the antihistamine ebastine

1. We have given 12 healthy subjects the H1-antihistamine ebastine (20 mg) or placebo in a randomized double-blind and crossover study for 1 week each. The subjects were tested for drug effects on day 6 of each period, and for interactions of ebastine with oral 15 mg diazepam (DZ) on day 7. On both days, the testing runs were at baseline and 1.5, 3, 4.5 and 6 h after intake. 2. The performance was evaluated both objectively (digit symbol substitution, flicker fusion, Maddox wing, simulated driving, body balance) and subjectively (visual analogue scales, questionnaires). Venous blood was sampled daily during the maintenance and during each testing round for the assay of plasma carebastine (the active metabolite of ebastine) by high pressure liquid chromatography and plasma diazepam by radioreceptor assay. Three-way ANOVA, paired t-test, Wilcoxon rank sign test and Fisher's fourfold table test were used for data analysis. 3. Plasma carebastine reached steady levels from day 3 onwards. The mean concentrations in the morning were 82 micrograms l-1 on day 6 and 85 micrograms l-1 on day 7. The rise (+ 150%) in plasma carebastine after an extra 20 mg ebastine was not modified by DZ. Ebastine did not affect performance objectively or subjectively, yet borderline drowsiness was recorded during the first 3 h. On day 7, plasma DZ concentrations peaked (mean 480 micrograms l-1) at 1.5 h after the intake. DZ produced impaired performance in various objective tests, and drowsiness, weakness, clumsiness, mental slowness and poor performance were reported on visual analogue scales.(ABSTRACT TRUNCATED AT 250 WORDS)

Caffeine Moderately Antagonizes the Effects of Triazolam and Zopiclone on the Psychomotor Performance of Healthy Subjectsf

To determine whether caffeine antagonizes the decremental effects of triazolam and zopiclone on human performance, oral single doses of 0.250 mg triazolam, 7.5 mg zopiclone, or respective placebos, with and without 300 mg caffeine, were given to parallel groups of student volunteers in two double-blind studies. Objective tests and subjective visual analogue ratings were done at baseline and 30 min. and 90 min. after the intake. In Study I, triazolam produced drowsiness at 30 min. but did not differ from the placebo in other tests. Caffeine induced alerting effects in various tests and differed from triazolam in some (digit substitution, drowsiness, calmness, mental slowness) but not all variables measured. Caffeine and triazolam were interpreted as being antagonists. In Study II, zopiclone impaired digit substitution and flicker fusion, produced exophoria and lowered systolic blood pressure. Caffeine differed from zopiclone in several test functions, but it also differed from caffeine + zopiclone whereas zopiclone differed from caffeine + zopiclone only in two tests (Maddox wing, systolic blood pressure). Thus, zopiclone counteracted the effects of caffeine more easily than caffeine counteracted the decremental effects of zopiclone. We conclude that triazolam may not differ importantly from diazepam as regards their antagonism towards caffeine, whereas further research on the antagonism between zopiclone and caffeine needs to be done.

Lack of pharmacodynamic and pharmacokinetic interactions of the antihistamine ebastine with ethanol in healthy subjects

We have given 12 healthy subjects the H1-antihistamine ebastine (20 mg) or placebo in a double-blind, crossover study for one week each. The subjects were tested for drug effects on Day 6 of each period, and for interactions of ebastine with ethanol (0.8 g.kg-1) on Day 7. On both days, the testing runs were done at baseline and at 2, 4, and 6 h after the drug. Performance was evaluated both objectively (digit symbol substitution, flicker fusion, Madox wing, nystagmus, simulated driving, body balance) and subjectively (visual analogue scales) and with questionnaires. Venous blood samples were taken daily during maintenance and during each test run for assay of plasma carebastine. Blood ethanol concentrations were assayed with an Alcolmeter in the breath and directly in the blood. Plasma carebastine concentration reached a steady-state from Day 3 on; the mean concentrations in the morning were 92 micrograms.l-1 on Day 6 and 104 micrograms.l-1 on Day 7. The rise in plasma carebastine after an extra 20 mg of ebastine was accelerated but not increased by ethanol. Ebastine did not impair performance objectively or subjectively. It slightly improved body balance and reduced errors during simple tracking at 4 h. Blood ethanol concentrations peaked (mean 0.76 g.l-1) at 1.5 h after ethanol intake. Ethanol impaired performance in most objective tests and produced clumsiness, muzziness, and mental slowness, but little drowsiness. Ebastine neither modified the blood ethanol concentrations nor increased the effects of ethanol.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of dexmedetomidine and midazolam on human performance and mood

The effects of dexmedetomidine (DXM), a novel alpha 2-adrenoceptor agonist, on human performance and mood were studied in a double-blind randomized crossover study in 12 healthy student volunteers. Single IM doses of dexmedetomidine, 0.6 microgram/kg (DXM1) and 1.2 micrograms/kg (DXM2), 80 micrograms/kg midazolam (MID) and saline placebo, were given at one-week intervals. Performance was measured objectively and mood was assessed subjectively with visual analogue scales (VAS) at baseline and 40 min, 2 h, 4 h and 6 h after each injection. Blood pressure and heart rate in the sitting position were measured and venous blood was sampled during each testing round. DXM1 did not significantly impair cognitive (digit symbol substitution), coordinative (tracking) or reactive skills, and at 6 h it shortened reaction time and reduced errors in complex tracking. It produced exophoria, increased body sway with the eyes open and impaired subjective performance on VAS. The higher dose dexmedetomidine also caused impaired cognitive, coordinative and reactive skills (although a trend towards improved coordination was found at 6 h), reduced attention, produced exophoria, increased body sway with the eyes open and caused drowsiness, clumsiness, passiveness and mental slowness on the appropriate VAS scales. MID resembled DXM2 in impaired objective and subjective measures of skilled performance, although the objective effects of MID were of speedier onset and shorter duration. In contrast to MID, DXM caused a significant and dose-dependent decrease in systolic and diastolic blood pressure still detectable 6 h after injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Steady state pharmacokinetics of piroxicam in children with rheumatic diseases

Ten children with rheumatoid arthritis, aged 7-16 y and weighing 20-63 kg, were treated with piroxicam mean dose 0.4 mg.kg-1 once daily for 2 weeks. On Day 15, blood was sampled from 2-120 h after the last dose. The Cmax for piroxicam ranged from 3.6 to 9.8 (mean 6.6) mg.l-1 and its half-life by log linear computation was 22 to 40 (mean 32.6) h. The volumes of distribution and the total body clearance were estimated as the ratio of actual volumes of distribution and actual clearances to availability. The volumes of distribution (V/F) were 0.12 to 0.25 (mean 0.16) l.kg-1, and the total body clearances (CL/F) were 2.1 to 5.0 (mean 3.4) ml.kg-1.h-1. Thus, piroxicam clearance in these patients was higher and its half-life was shorter than those previously reported in young adults, yet V appeared similar.

Efficacy and side-effects of prazosin as a symptomatic treatment of benign prostatic obstruction

This randomized double-blind crossover trial was conducted to assess the effects of prazosin, an alpha 1-adrenoceptor blocking drug, on the voiding of 35 patients with benign prostatic obstruction. Maximum and mean flow rates, residual urine, blood pressure and heart rate were measured at baseline and 2, 4, 6, and 8 weeks after starting the treatment with placebo or prazosin. At 4 weeks the treatments were switched over. The patients filled micturition charts at home and scored their voiding associated feelings. The maximum and mean flow rates increased significantly during prazosin treatment, as also did the maximum and mean voided volumes. Residual urine decreased and voiding improved subjectively but these changes were not statistically significant. Blood pressure was lowered and heart rate increased. Prazosin caused postural dizziness more often than placebo. Prazosin seems to offer an alternative to improve voiding in some patients with prostatic obstruction.

Morphine and oxycodone in the management of cancer pain: plasma levels determined by chemical and radioreceptor assays

Morphine and oxycodone were administered to ten patients suffering from severe cancer pain in a double-blind cross-over study. The patients titrated themselves pain-free, first intravenously, using a patient-controlled analgesia device, and then orally. Each titration phase lasted for 48 hours. Blood samples were drawn after 36 hr of each administration phase. The plasma levels of morphine, morphine-6- and morphine-3 glucoronides were determined with high performance liquid chromatography (HPLC), whereas the oxycodone samples were assayed with gas chromatography (GC). Twin samples were analyzed for plasma opioid activity with a radioreceptor assay (RRA) using 3H-dihydromorphine and 3H-naloxone as radioligands. Adequate analgesia was achieved with both morphine and oxycodone. About 30% more oxycodone was needed intravenously, whereas 25% less oxycodone than morphine was consumed orally. There was a good linear correlation between the morphine concentrations measured with HPLC and RRA. The mean morphine-6-glucuronide to morphine concentration ratio was 2.3 after intravenous and 4.6 after oral administration. Results from RRA indicate that oxycodone in vivo is a potent mu-agonist and that at least part of its analgesic action is mediated by active metabolites. In vitro morphine glucuronides enhanced morphine in displacing radioligands from the opioid receptors, thus suggesting their complex interactions in vivo.

Actions of zopiclone and carbamazepine, alone and in combination, on human skilled performance in laboratory and clinical tests

1. Possible interactions of zopiclone and carbamazepine on human skilled performance were studied in a randomized, double-blind, crossover trial with 12 healthy young subjects. 2. Psychomotor performance (coordination, reactions, attention, cognition) and subjective effects (VAS) were measured and venous blood sampled before and 1.5, 3, 4.5 and 6 h after single oral doses of placebo, 7.5 mg of zopiclone and 600 mg of carbamazepine, which were given alone or combined. Clinical test for drunkenness (CTD) was done 2 and 5 h after drug intake. 3. Both zopiclone and carbamazepine, when administered alone, impaired performance on laboratory tests, the decrements being recorded 1.5 to 6 h after intake. In line with the plasma concentrations, the zopiclone effects peaked earlier (at 1.5 h) and lasted for a shorter time than those of carbamazepine. Zopiclone had a more pronounced effect on perceptual and cognitive functions (digit substitution) and it affected extraocular muscle tone (Maddox wing), whereas carbamazepine had stronger effects on attention. Additive pharmacodynamic actions were found in most tests after the combined treatment with zopiclone and carbamazepine. 4. CTD proved to be less sensitive than the laboratory tests in revealing drug-induced decrement of performance after administration of one agent alone. However, it revealed the combined decremental effects of zopiclone and carbamazepine. 5. When the drugs were given together, the absorption of drugs was retarded. Carbamazepine-10,11-epoxide levels were lower after intake of the drug combination than those measured after intake of carbamazepine alone. 6. The results suggest that the clinical tests developed to detect alcohol effects do not necessarily reveal drug-induced impairment of performance.

Effects of remoxipride on psychomotor performance, alone and in combination with ethanol and diazepam

The effects of remoxipride, alone and in combination with ethanol and diazepam, on sensory, cognitive, and neuromotor performance were studied in 12 healthy volunteers (7 men, 5 women). The study was of double-blind randomized, crossover design with each subject receiving six different single-dose experimental treatments at six sessions. Tests of sensory, cognitive, and neuromotor functions were carried out, together with subjective assessments. Remoxipride alone seemed to have no effect on the sensory functions measured, but it affected cognitive and neuromotor functions to a limited extent. In general the effects of ethanol and diazepam alone were more pronounced than those of remoxipride. When remoxipride was combined with either ethanol or diazepam, there was a tendency for the effect to be additive.

Actions and interactions of hypnotics on human performance: single doses of zopiclone, triazolam and alcohol

Actions and interactions with ethanol (0.8 g/kg) of triazolam (TRZ, 0.25 mg) and zopiclone (ZOP, 7.5 mg) on performance and memory were studied with 12 healthy young subjects. The randomized double-blind and crossover test sessions were carried out at 1-week intervals. Each time a set of performance tests and self-assessments on visual analogue scales were done before the treatment and 1.5, 3, 4.5, 6 and 8 h after it. The clinical test for drunkenness (CTD) was done 2 and 5 h after drug intake. Venous blood was sampled after each set of tests. Both TRZ and ZOP impaired coordinative and reactive skills, but not peripheral attention or body balance. They also impaired cognitive test performance (digit substitution, symbol copying), and lowered flicker fusion threshold. The psychomotor effects of the two hypnotics and measures of subjective sedation peaked at 1.5 and 3 h. Spatial memory was impaired by TRZ at 4.5 h. Cognitive tests and tracking were most sensitive to alcohol. Furthermore alcohol impaired both motor and vestibular aspects of the CTD while both ZOP and TRZ alone had only minor effects. Alcohol enhanced and prolonged the effects of both hypnotics without modifying their plasma concentrations. Drug-alcohol interactions were mainly additive though more obvious with TRZ. Interactions were evident also on the CTD. The hypnotics were free from residual psychomotor and cognitive effects at 8 h even after the coadministration of alcohol. It is concluded that ZOP and TRZ have a mainly additive interaction with alcohol but pharmacokinetic mechanisms do not seem to contribute essentially to this.

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)

Psychomotor, respiratory and neuroendocrinological effects of a mu-opioid receptor agonist (oxycodone) in healthy volunteers

Psychomotor performance related to driving and occupational skills was measured double-blind and cross-over in 9 healthy volunteers before and 1.5, 3 and 4.5 hr after intramuscular injection of oxycodone (0.13 mg/kg), oral diphenhydramine (100 mg) and placebo. The effects of oxycodone on performance peaked at 1.5 hr when it prolonged reaction time and impaired vigilance, attention, body balance and coordination of extraocular muscles. The subjects assessed themselves mentally slow, muzzy and impaired by performance on visual analogue scales still 3 hr after injection. Critical flicker discrimination was impaired and some respiratory depression still present at 4.5 hr after administration. Oxycodone elevated plasma prolactin at 1.5 and 3 hr while growth hormone levels remained unaffected. We conclude that the profile of psychomotor decrement produced by this mu-opioid agonist closely resembles that of agonist-antagonist analgesics.

Actions and interactions of psychotropic drugs on human performance and mood: single doses of ORG 3770, amitriptyline, and diazepam

Actions and interactions of two antidepressants and diazepam on human skilled performance and mood were studied in a randomized double-blind cross-over trial with single oral doses of 50 mg amitriptyline (AMI), 15 mg Org 3770 (ORG) and placebo, given alone and in combination with 15 mg diazepam (DZ) to 12 young healthy subjects at one-week intervals. Objective tests (digit substitution, tapping, flicker fusion, Maddox wing, tracking, choice reactions, body sway, memory) and subjective assessments (visual analogue scale) were performed at baseline and 1.5, 3, 4.5 and 6 hours after drug administration. Side-effects were reported, blood pressure and heart rate measured and blood samples taken after each testing run. Placebo was nearly inert on performance and mood. DZ impaired some objective skills and showed sedative effects in the subjective tests. AMI produced sedation and impaired coordination as well as cognitive performance (digit substitution), most clearly at 3 to 4.5 hr. ORG resembled AMI in impairing objective and subjective performance, however, not necessarily in the same tests. Their combined effects with DZ were additive in objective tests but less additive in subjective tests. The drug combinations, but not any single drug, impaired learning acquisition. Plasma concentrations of the drugs given alone were about as expected, without important interactions. We conclude that the combinations of benzodiazepines with the antidepressants used impair skilled performance but may not cause major hazards.

Psychomotor performance of patients with rheumatoid arthritis: cross-over comparison of dextropropoxyphene, dextropropoxyphene plus amitriptyline, indomethacin, and placebo

Actions on performance of dextropropoxyphene (DXP) alone and in combination with amitriptyline (AMI), indomethacin (IN), and placebo were compared in 15 patients with rheumatoid arthritis. The patients were on their prescribed maintenance regimen excluding analgesics. In four randomized test sessions at two-week intervals, they received double blind and crossover single oral doses of DXP 130 mg, IN 50 mg, DXP 65 mg + AMI 25 mg or placebo, each after two days' pretreatment with the same drug. Objective and subjective effects were measured at baseline and 2 and 4 hours after drug administration. DXP impaired critical flicker discrimination, symbol copying and body balance without modifying tracking, choice reactions or attention. It rendered the subjects elated, muzzy, mentally slow and calm. Actions of AMI + DXP were about the same. IN impaired body balance and critical flicker recognition. Plasma concentrations of DXP were moderate to high whilst those of IN and AMI were fairly low. We conclude that therapeutic doses of DXP and IN are relatively safe in regard to driving skills. Small doses of AMI may not enhance the mild psychomotor effects of DXP. Earlier single dose studies carried out with healthy volunteers might have overestimated the decremental effects of analgesics on psychomotor performance.

Acute effects of sertraline, amitriptyline, and placebo on the psychomotor performance of healthy subjects over 50 years of age

A double-blind, placebo-controlled, crossover study in 12 subjects (greater than or equal to 50 years) compared the effects of single oral doses of sertraline (100 mg) and amitriptyline (50 mg) with placebo as assessed by psychomotor function testing. Unlike sertraline and placebo, amitriptyline increased tracking error severity and impaired digit/symbol substitution. Sertraline slightly improved flicker frequency recognition. Both active drugs caused subjective drowsiness, although amitriptyline's effect was greater and of longer duration. Both drugs impaired subjectively assessed performance. Sertraline caused nausea, and amitriptyline, dry mouth; sertraline tended to increase supine systolic blood pressure. The authors conclude that sertraline has a considerably less detrimental effect on psychomotor performance and may have a slight activating effect not found with amitriptyline.

Anxiogenic effect of yohimbine in healthy subjects: comparison with caffeine and antagonism by clonidine and diazepam

Three placebo-controlled double-blind and crossover trials were carried out to analyze the effects of oral yohimbine (YOH) 0.8 mg/kg on mood and performance in 16 healthy students. Subjective assessments (visual analogue scales, side-effects on questionnaire) and objective measurements (digit symbols, flicker fusion, tapping, heterophoria) were done at baseline, and post treatment. YOH shifted the healthy subjects' mood towards feeling panicked, elevated systolic blood pressure and plasma prolactin concentrations, reduced digit symbol substitution, and induced drowsiness and passiveness. Caffeine (CAF) 10 mg/kg raised plasma cortisol and rendered the subjects slightly panicked. Muzziness, clumsiness, tremor, chills and nausea were common after both YOH and CAF. Diazepam (DZ) 0.3 mg/kg given at 60 min antagonized some effects of CAF but failed to antagonize YOH. Clonidine (CLO) 100 micrograms counteracted YOH effects on blood pressure but less the subjective and hormonal effects. CLO 200 micrograms partly antagonized the pressor, sedative but not the hormonal responses of YOH. DZ counteracted YOH effects on plasma cortisol on panic but not on other subjective measures or plasma prolactin. Since CLO did not abolish YOH-induced prolactin increase, it is suggested that these effects of YOH are mediated not only via adrenergic alpha 2-receptors; other mechanisms made important contributions.

Parenteral pentazocine: effects on psychomotor skills and respiration, and interactions with amitriptyline

The combined effects on performance and respiration of pentazocine (PZ) and amitriptyline (AMI) were evaluated in a double-blind cross-over study in 11 healthy students. After pretreatment for 1 week with AMI or placebo, on Day 8 the subjects received placebo or 50 mg p.o. AMI and 30 mg PZ or saline i.m. so that the final treatments were 1) placebo, 2) acute AMI 50 mg, 3) acute PZ, 4) subchronic AMI + acute PZ and 5) subchronic AMI. The subacute treatments were started at two-week intervals. Objective and subjective performance tests and respiratory function (minute volume, ETCO2) were measured. Parenteral PZ impaired sensory processing (digit symbol substitution, choice reactions) and extraocular muscle balance (Maddox wing) but left motor skills (tracking, tapping speed) unaffected. A single oral dose of AMI 50 mg affected both sensory and motor performance. The psychomotor effects of PZ were clearest at 1.5 h, and those of AMI at 3.5 h. Both drugs rendered the subjects drowsy, clumsy, and muzzy on visual analogue scales, but PZ also induced positive feelings, like contentedness and friendliness. PZ depressed respiration in terms of lowered minute volume and elevated ETCO2, and subchronic AMI increased this depression. The chemically assayed plasma concentrations of AMI and PZ were as expected; radioreceptor assay revealed low or negligible mu-opiate activity in plasma after PZ. The results suggest that AMI does not enhance the moderate psychomotor decrement produced by PZ. However, respiratory depression may be increased by their concomitant use.

Acute effects of maprotiline, doxepin and zimeldine with alcohol in healthy volunteers

In a double-blind and cross-over trial, 12 healthy volunteers received single oral doses of maprotiline 75 mg, doxepin 25 mg, zimeldine 200 mg and placebo, alone and with alcohol (1 g/kg), at one-week intervals. Objective tests of performance (tracking, choice reaction, flicker fusion, body sway, nystagmus, Maddox wing) and ratings of subjective feelings were done before the drug intake (baseline) and 1 1/2, 3, 4 1/2, 6 and 7 1/2 hr after it. Maprotiline and doxepin proved subjectively sedative, whilst doxepin and zimeldine prolonged choice reaction time. An increase of alcohol effects was seen clearly after doxepin, to lesser extent after maprotiline and not at all after zimeldine. On the contrary, zimeldine antagonized alcohol-induced impairment in the tracking test.

Effects of the novel 5-hydroxytryptamine reuptake inhibitor indalpine and ethanol on psychomotor performance

Twelve healthy male volunteers were treated double-blind and cross-over with 4-(3-indolyl-2-ethyl)piperidine (indalpine), a selective 5-hydroxytryptamine uptake inhibitor with antidepressant and anxiolytic properties, and placebo for two weeks. Soon after starting the treatment with indalpine (50 mg/d) they felt subjectively mild sedative-like effects which were abolished when retested after two weeks' maintenance (150 mg/d). Objectively measured psychomotor performance (coordinative and reactive skills, standing steadiness, nystagmus, flicker recognition) was not, however, affected by indalpine. The only adverse effect attributable to indalpine was ejaculatory dysfunction which was spontaneously reported by 67% of the subjects. When alcohol (1 g/kg) was administered during the treatment periods most tests showed impairment. However, indalpine neither enhanced nor counteracted the effects of alcohol in this trial.

Objective and subjective assessments of the effects of flupentixol and benzodiazepines on human psychomotor performance

The aim of this double-blind crossover trial was to compare the objective and subjective effects of flupentixol and lorazepam on human performance, and to reveal possible interactions between flupentixol and diazepam. Twelve healthy students received at 1-week intervals oral single doses of flupentixol 1 mg, flupentixol 2 mg, lorazepam 2.5 mg, placebo, and diazepam 15 mg alone and with flupentixol 1 mg. After the baseline measurements, the drugs were given in capsule form, and the tests were repeated 1.5, 3 and 4.5 h later. Diazepam was given at 1.5 h, to time its peak effect to coincide with that of lorazepam. Drug effects were measured objectively (two tracking tests, digit substitution, letter cancellation, flicker fusion, Maddox wing, tapping, memory) and subjectively (visual analogue scales, questionnaire). Blood samples were taken after each test time. Flupentixol 1 mg did not differ from placebo objectively or subjectively. Flupentixol 2 mg proved nearly inert objectively and on visual analogue scales. Lorazepam impaired objectively measured test performance, the clearest effects occurring at 3 and 4.5 h. It also impaired subjectively assessed performance. Diazepam impaired objective performance less than lorazepam, its effects peaking at 1.5 h after intake. Diazepam caused subjective drowsiness, clumsiness, mental slowness etc. as much as or more than lorazepam. The combination of 1 mg flupentixol and diazepam modified performance as much as diazepam alone. After the administration of 1 mg flupentixol, plasma concentrations were undetectable and levels after 2 mg were hardly detectable. Concentrations of lorazepam exceeded those of diazepam in direct bioassay, but they were much lower when bioassayed after solvent extraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective and subjective effects of remoxipride, alone and in combination with ethanol or diazepam, on performance in healthy subjects

Effects on human performance of remoxipride (RX), an antipsychotic drug of substituted benzamide structure, were studied in a randomized double-blind crossover trial where 12 young healthy volunteers took at 1 week intervals single oral doses of placebo or remoxipiride 100 mg both alone and in combination with 15 mg diazepam (DZ) or 0.8 g/kg ethanol (EtOH). Objective (digit symbols, tracking, choice reaction, flicker fusion, Maddox wing, body balance, memory) and subjective (visual analogue scales, questionnaire) tests were administered at baseline and 1.5, 3, 4.5 and 6 h post-treatment.

A new device to measure drug-induced changes on reactive and coordinative skills of human performance

A computerized device for simultaneous measurement of coordinative and reactive skills related to driving was developed and tested in two consecutive trials of psychoactive agents in healthy volunteers. The test system comprises a vehicle, a driving computer (Sinclair QL), and the programming and measurement computer (IBM-PC). The computerized driving programme projects to the colour--TV screen a winding road, and the driver has to keep the car on the road by turning the steering wheel. The driving proceedes at a fixed, fairly rapid rate for 5 min., and the numbers of tracking errors (deviations from the road) as well as the tracking percentage (relative length of the track driven off the road) were computed separately for both halves of the track. During the latter half of the track 60 visual or/and sound stimuli were given in random order, and the driver had to respond or not respond to them by pressing a button or by pushing a foot pedal. The number of reaction errors and the cumulative reaction time were recorded. The programme also provides a histogramme that relates the number of deviations from the road to their duration, enabling a visual judgement of the severity of errors. Matched versions (mirror image, reverse direction) of tracks of varying severity were offered to reduce learning effect during the trial. When testing the device in two placebo-controlled double-blind and cross-over trials, a considerable practice effect on tracking and reaction strategies took place, but after proper training the baselines remained reasonably stable.(ABSTRACT TRUNCATED AT 250 WORDS)