Lisuride, a dopamine receptor agonist with 5-HT2B receptor antagonist properties: absence of cardiac valvulopathy adverse drug reaction reports supports the concept of a crucial role for 5-HT2B receptor agonism in cardiac valvular fibrosis.

OBJECTIVES: The high incidence of fibrotic cardiac valvulopathies reported in association with the 8beta-ergoline dopamine (DA) agonist, pergolide, and also case reports for cabergoline and bromocriptine have made it necessary to review the theoretical basis and actual findings in the case of another DA agonist, the 8alpha-ergoline lisuride (used since the 1970s for migraine prophylaxis as well as since the 1980s for its prolactin-lowering and anti-Parkinson activity). METHODS: We have reviewed the pharmacology of lisuride in relation to other DA agonists, and we have performed a throughout literature search as well as a search of our own and other adverse drug reaction databases for a possible relationship of lisuride with cardiac valvulopathy or for any reports of fibrosis in other locations. RESULTS: Our review of the pharmacology and the literature strongly suggests that drug-induced cardiac valvulopathies are always related to a stimulatory drug effect on trophic 5-HT(2B) receptors. As lisuride is devoid of such an effect, but on the contrary is an extremely potent 5-HT(2B) antagonist, an association of lisuride therapy with cardiac valvulopathies seems to be highly unlikely. In agreement with this hypothesis, not a single report of a cardiac valvulopathy associated with lisuride therapy has been identified in any database so far.Furthermore, against a background of an estimated 360,000 patient years, we have found only a very small number of cases of any other form of fibrosis (1x retroperitoneal, 2x pleural, 2x pulmonary, 1x interstitial pulmonary changes), in part combined with other risk factors and confounding variables. This closely matches 4 reports available from WHO (1x retroperitoneal, 3x pleural fibrosis). In addition, only 5 other possibly related conditions (3x pleural effusion, 1x pleuritis, 1x pericarditis) were identified in the lisuride adverse drug reaction database of Schering, Berlin. CONCLUSIONS: No link has been found between lisuride use and fibrotic cardiac valvulopathy, in agreement with the 5-HT(2B) receptor antagonist effect of this drug. The very low incidence of spontaneous reports of any other fibrosis could be even compatible with an association by chance in the population exposed to lisuride. Although close monitoring for this kind of side effects is still to be recommended in the therapy with lisuride, our data do not support the concept of a class effect suggesting that all ergot-derived drugs and especially DA receptor agonists with some chemical similarity to the ergot structure will cause or facilitate cardiac valvulopathies as observed with pergolide.

Chronic treatment of pathological hyperprolactinemia and acromegaly with the new ergot derivative terguride.

The long term effectiveness and tolerance of terguride, a new ergot derivative, as initial therapy were evaluated in 20 patients with pathological hyperprolactinemia (PHP; group A) and 7 patients with acromegaly. We also studied 10 patients with PHP whose treatment was changed from bromocriptine or lisuride to terguride (group B). Terguride, given for at least 6 months in divided doses ranging from 0.25-1.50 mg/day to group A patients, resulted in normal (11 patients) or markedly reduced plasma PRL levels. Gonadal function was restored in all but 2 patients in this group, and the tumors shrank in 3 of 5 patients with a macroprolactinoma and in 1 of 3 patients with a microprolactinoma. In group B patients, positive effects of the previous treatment on PRL levels, gonadal function, and tumor growth were maintained by terguride. Terguride suppressed plasma GH levels below 50% of baseline in 4 of the 7 acromegalic patients. Two of the 27 patients initially treated with terguride complained of mild nausea and postural hypotension only after the first dose (0.25 mg) of the drug. No patient in group B had any side-effects during terguride, with the exception of 1 patient who was also intolerant to bromocriptine. We conclude that terguride is an effective well tolerated dopaminergic agent in PHP.

Disposition of oral lisuride in Parkinson's disease.

The single and multiple oral dose plasma kinetics of lisuride were followed by a recently developed radioimmunoassay method in 11 patients with Parkinson's disease. A very wide range of plasma drug concentrations resulted from a single dose of 300 micrograms, as reflected in large interindividual differences in peak concentration (0.27 to 3.30 ng/ml) and AUC after the initial dose (43.1 to 617 ng X min/ml). Absorption was rapid, with a mean time to peak of 39 min. Only 0.05% of the dose was excreted unchanged in urine in 24 hr. There was a 110% increase in apparent oral clearance after 2 to 4 wk of treatment.

Synthesis, chemical, and biological properties of vinylogous hydroxamic acids: dual inhibitors of 5-lipoxygenase and IL-1 biosynthesis.

Vinylogous hydroxamic acids (3-(N-hydroxy-N-alkylamino)-2-propen-1-ones, VHA) were prepared as antiinflammatory agents. The synthesis, chemical properties, and in vitro biological activities of these relatively unexplored compounds are described. The VHAs were prepared by condensation of the appropriate N-substituted hydroxylamine with any of the three reagents: a 1,3-dicarbonyl compound (method A); a vinylogous amide (method B); or an alkynone (method C). The VHAs exist as one or more tautomers in solution with the relative proportions of each being dependent upon the structure of the VHA, solvent, and pH. VHAs undergo some of the typical reactions of hydroxamic acids as well as those of vinylogous amides. VHAs are active as inhibitors of 5-lipoxygenase and of IL-1 biosynthesis in vitro, which do not inhibit other enzymes of the arachidonic acid cascade. They have been shown by ESR studies to bring about inhibition of soybean type 1 15-lipoxygenase by reduction of the active site iron.

Sleep EEG evaluation: a comparison of results obtained by visual scoring and automatic analysis with the Oxford sleep stager.

Oxford Medical has introduced an automatic sleep stager based on the stage-scoring criteria by Rechtschaffen and Kales. With our study we intended to examine whether the results of the stager (version 3.0) match those of the visual evaluation by two independent raters. We also wanted to test the reliability of this automatic sleep stage-scoring system. Ten somnopolygrams of subjects without sleep disturbances served as a basis for the comparison. Each sleep recording was scored twice automatically by the stager, twice visually by the first rater, and once by the second rater. The two automatic analyses of the somnopolygrams differed by 4.3% in a total of 13,850 epochs (1 epoch delta 20 s) regarding sleep stage scoring. The difference between the first and the second visual evaluation by the same rater amounted to 5.7%, whereas the results of the two independent raters deviated by 8.7%. Compared with the results of the visual analysis reached as a consensus by both raters--the so-called optimized visual analysis--the stager showed a 26.9% difference. The automatic analysis scored fewer epochs as stages wake, rapid eye movement (REM), and 2 and more as stages 1, 3, and 4. The sleep stager's frequent difficulty in identifying stage wake correctly as well as its incorrect allocation to other stages--mainly stage REM--could lead to misinterpretations of sleep recordings, whereas the increase in stages 1, 3, and 4, as compared with visual scoring, was negligible.

Immune factors in narcolepsy.

Most but not all subjects with the narcoleptic syndrome have the human leukocyte antigen (HLA) DR2 (and DQ1). The narcolepsy-DR2 association is the highest disease-HLA linkage known, and occurs in nonfamilial as well as familial cases of the narcoleptic syndrome. In other forms of daytime drowsiness, there is no relationship with a specific HLA, although some subjects considered to have "essential" hypersomnolence probably have the narcoleptic syndrome. The cause of the narcoleptic syndrome remains unknown, although in a few instances the condition follows infection. There is no evidence for a circulating sleep factor in the blood or in the cerebrospinal fluid of narcoleptic subjects, and no unequivocal marker of cellular immunity has yet been found. However, a few subjects with the narcoleptic syndrome have oligoclonal bands or raised immunoglobulin concentration in the cerebrospinal fluid. It is highly likely that the narcoleptic syndrome is an immune-mediated disorder, occurring in a genetically susceptible (DR2/DQ1-positive) subject.

Amnestic effects of lormetazepam and their reversal by the benzodiazepine antagonist Ro 15-1788.

A combined visual (pictures) and auditory (word lists) memory test developed to trace the course of information processing under pharmacological or other influences was validated in a group of 20 subjects (control group) and then applied to determine the amnesic effects of lormetazepam and the reversal of these effects by the benzodiazepine antagonist Ro 15-1788. Three groups of n = 10 subjects received either 0.02 mg/kg IV lormetazepam (groups B and C) or placebo (group A) followed 14 min later by 0.03 mg/kg IV Ro 15-1788 (groups A and C) or placebo (group B). The time course of memory performance in the three groups was investigated and compared across three consecutive 14-min phases: before (phase 1) and after (phase 2) the first intravenous administration, and after the second treatment (phase 3). Results were also compared with those of 20 subjects from a drug-free control group in order to verify the memory test. Lormetazepam clearly impaired immediate and delayed free recall as well as recognition in both visual and auditory tasks. These effects were completely reversed by Ro 15-1788, which alone had no clear effect on memory performance in this study. Psychometric scales indicated concomitant sedation and impaired concentration after lormetazepam alone. Interestingly, lormetazepam retrogradely enhanced performance in the visual test of delayed free recall. The impaired acquisition of new information after the administration of lormetazepam may be associated with an improvement of the consolidation process of information acquired before drug treatment.

Changes in noradrenaline plasma levels and behavioural responses induced by benzodiazepine agonists with the benzodiazepine antagonist Ro 15-1788.

Noradrenaline (NA) plasma levels were examined in 18 healthy volunteers on 2 consecutive days after a single treatment with either lormetazepam (0.06 mg/kg) (LMZ group), flunitrazepam (0.03 mg/kg) (FNZ group) or placebo (PLA group) in combination with the benzodiazepine (BZ) antagonist Ro 15-1788 (0.1 mg/kg). Behavioural responses (mood changes, anxiety) were also investigated in parallel. Both BZ decreased NA plasma levels to 50% of the basal values 10 min after the injection; administration of Ro 15-1788 15 min later reinstated NA plasma levels to basal values. A second administration of Ro 15-1788 (0.1 mg/kg) 24 h after BZ or PLA treatment increased NA plasma levels, estimated 10 min after the injection in both the LMZ- and the FNZ groups, but not in the PLA group. Behavioural responses measured under the same treatment also indicated minor anxiety responses followed by mood impairment. These data suggest that a stressful situation may be precipitated by the antagonist Ro 15-1788 24 h after a single BZ treatment, which resembles a withdrawal response, and increases NA plasma levels.

Human studies on the benzodiazepine receptor antagonist beta-carboline ZK 93,426: preliminary observations on psychotropic activity.

The beta-carboline ZK 93,426, a benzodiazepine receptor antagonist, was administered intravenously to human volunteers at two different doses (0.01 mg/kg, 0.04 mg/kg) according to a double-blind, placebo controlled design. Vital functions (i.e. blood pressure, heart rate, ECG, EEG), peripheral (finger) skin temperature and performance in psychometric tests for psychotropic and cognitive effects were evaluated. Blood samples were collected in addition and certain pharmacokinetic parameters were estimated. ZK 93,426 in both doses was well tolerated and exhibited no side effects. A decrease in peripheral skin temperature and heart rate was observed. In a general estimation of behavioural changes, volunteers experienced a stimulant and activating effect of the drug. An improvement in performance was observed in two cognitive tasks, the "logical reasoning task" and "pictures differences task" which estimated concentration and attention, respectively. No effects were found in time estimation. Plasma levels 5 min after intravenous administration of ZK 93 426 were 16 +/- 10 ng/ml and 52 +/- 31 ng/ml for 0.01 mg/kg and 0.04 mg/kg, respectively. Total clearance was calculated as 46 +/- 22 ml/min/kg (0.04 mg/kg).

Human studies on the benzodiazepine receptor antagonist beta-carboline ZK 93 426: antagonism of lormetazepam's psychotropic effects.

The effects of lormetazepam (0.03 mg/kg IV) a benzodiazepine (BZ) derivative in combination with ZK 93 426 (0.04 mg/kg IV) a beta-carboline, benzodiazepine receptor antagonist were evaluated in humans. Independently, the effects of ZK 93 426 on its own were investigated. A psychometric test battery to evaluate sedation (visual analog scales (VAS), anxiolysis (state-trait-anxiety inventory scale (STAIG X1) and cognitive functions [logical reasoning test (LR), letter detection test (LD)] was applied before and several hours after initiation of treatment. Multiple sleep latency test (MSLT), which measures day time sleepiness, was also applied. Vigilosomnograms analysed from standard EEG recordings were evaluated shortly before and for 1 h after treatment. Treatment started with an intravenous injection of either lormetazepam (LMZ) or placebo (PLA), which was followed 30 min later by administration of either ZK 93 426 or placebo; thus four treatment groups were created (PLA + PLA, LMZ + PLA, LMZ + ZK 93 426 and PLA + ZK 93 426). ZK 93 426 antagonized the sedative and hypnotic effect of LMZ as estimated by MSLT and vigilosomnograms, respectively. Impairment of cognitive functions (LR and LD) induced by LMZ was also antagonized by ZK 93 426. ZK 93 426 had no effect on the changes in the time estimation seen in the LMZ group. Furthermore, ZK 93 426 on its own increased vigilance (alertness) as measured by the vigilosomnogram. A competitive antagonism at the benzodiazepine binding site between ZK 93 426 and LMZ is suggested by their combination effects; the intrinsic activity of ZK 93 426 seems to be due to its weak partial inverse agonist component.

An efficient chiral moderator prepared from inexpensive (+)-3-carene: synthesis of the HIV-1 non-nucleoside reverse transcriptase inhibitor DPC 963.

The beta-amino alcohol 4 beta-morpholinocaran-3 alpha-ol is prepared by addition of morpholine to alpha-3,4-epoxycarane utilizing anhydrous magnesium bromide as Lewis acid promoter. The enantiopure amino alcohol is uniquely effective as a chiral moderator for the addition of lithium cyclopropylacetylide to an unprotected N-acylketimine. This reaction provides an efficient route to the second generation NNRTI drug candidate DPC 963.

Clinical perspectives of beta-carbolines from first studies in humans.

First results from studies in healthy subjects with the beta-carbolines ZK 91 296, ZK 95 962 and ZK 93 426 are reviewed. ZK 91 296 and ZK 95 962, characterized as partial benzodiazepine agonists in preclinical research, were unable to induce some typical benzodiazepine effects like sedation when administered intravenously in high doses. ZK 95 962, reported to be effective in photoepileptic patients, was able to reverse lormetazepam-induced sleep as documented by EEG-parameters. The benzodiazepine receptor antagonist ZK 93 426 dose-dependently elicited alertness, restlessness and mild apprehension--symptoms opposite those known for the benzodiazepines. The activating effect of ZK 93 426 was confirmed by the results from e.g., self-rating scales and the logical reasoning test. In another placebo-controlled study comparing the effects of ZK 93 426 alone and in combination with lormetazepam vigilosomnograms obtained after ZK 93 426 alone clearly confirmed the activating effect. In combination with lormetazepam ZK 93 426 was able to reverse the benzodiazepine induced sleep. The attenuation of benzodiazepine effects was also evident from multiple sleep latency tests. Our results support findings from animal experiments which classify these beta-carbolines as benzodiazepine receptor ligands with partial agonist and antagonist properties. beta-Carbolines may prove to be beneficial drugs in the treatment of anxiety, convulsions and diseases with an impairment of cognitive functions as well as in the reversal of unwanted benzodiazepine effects.

Novel 8 alpha-ergolines with inhibitory and stimulatory effects on prolactin secretion in rats.

Four derivatives of the ergot dopamine (DA) agonist lisuride (LIS), namely 6-n-propyl-lisuride (6-n-propyl-LIS), transdihydrolisuride (TDHL), 6-n-propyl-transdi-hydrolisuride (6-n-propyl-TDHL) and 2-bromolisuride (2-Br-LIS) were investigated in female rats with regard to their influence on hyperprolactinaemia induced by pretreatment with reserpine (2 mg/kg i.p., 24 h) at various intervals following their subcutaneous or oral administration (0.05 mg/kg). Two hours after administration, LIS, 6-n-propyl-LIS, and 6-n-propyl-TDHL caused a statistically significant inhibition of reserpine-induced hyperprolactinaemia of about the same extent. Eight hours after administration 6-n-propyl-LIS and 6-n-propyl-TDHL were as active as after 2 h in inhibiting prolactin (PRL) secretion whereas LIS was almost ineffective in this respect. TDHL caused a statistically significant inhibition of PRL secretion at 2 and 8 h after oral administration; this effect was less pronounced after s.c. administration. In contrast to the aforementioned derivatives 2-Br-LIS further increased the reserpine-induced hyperprolactinaemia. In normal male rats pretreatment with 2-Br-LIS (0.025-6.25 mg/kg s.c., 2 h) dose-dependently stimulated PRL secretion. The present data support the assumption of the longlasting DA agonistic action of 6-n-propyl-LIS and 6-n-propyl-TDHL and of the antidopaminergic properties of 2-Br-LIS recently derived from behavioural studies.

Scopolamine-induced amnesia in humans: lack of effects of the benzodiazepine receptor antagonist ß-carboline ZK 93426.

It has been suggested from pharmacological studies in animals that ZK 93426 may improve memory and other cognitive processes in humans. Scopolamine has been used to model aspects of memory impairment. To test the effects of ZK 93426 alone and in combination with scopolamine, ZK 93426 (0.04 mg/kg) or vehicle (Intralipid R) was administered intravenously (i.v.) to normal controls, pre-treated with either scopolamine 0.5 mg administered subcutaneously (s.c.) or the same volume of saline. A visual (presentation of pictures) and a verbal (words list) memory test were applied. Both drugs on their own and in combination were found to be safe and well tolerated. ZK 93426 did not antagonize the scopolamine-induced impairment of acquisition of the words list. Scopolamine did not impair delayed recall of visual or verbal material. ZK 93426 alone improved performance in delayed recall of visual material presented after drug application, whereas it impaired performance in delayed recall of visual material presented before drug administration.

Pharmacokinetic and clinical studies with a benzodiazepine radioreceptor assay.

Since the presence of benzodiazepine (BD) receptors was demonstrated in mammalian brain tissue, simple, sensitive and rapid techniques have been established to use BD-receptor preparations for specific radioreceptor assays (RRA). The RRA allows in vitro estimations of receptor affinity and concentration of BD in biological material, e.g. the time course of total BD binding activity in plasma (parent compound and active metabolites) may be evaluated. Several studies in volunteers with short and long-acting BD used as sedatives and hypnotics including diazepam (DZP), flunitrazepam (FNZ), flurazepam (FZP), lormetazepam (LMZ), oxazepam, temazepam and triazolam indicate that pharmacokinetic data (e.g. elimination half-lives of receptor active compounds) concur with the results obtained from other methods, if active metabolites are taken into account. For the evaluation of BD long-term and hangover effects in two placebo controlled double-blind studies (placebo vs. 1 mg and 2 mg LMZ, 2 mg FNZ, 30 mg FZP, 10 mg DZP) BD-binding equivalents and pharmaco-EEG recordings, subjective state, psychomotor as well as cognitive function were determined by standardized methods up to 154 hours following drug administration. Compared to placebo a distinct long-lasting increase in the relative power in beta-frequencies (12.5-30 Hz) and an impairment of psychomotor performance could be evidenced up to 12 h following FNZ and FZP intake. These effects correspond to the BD-binding activity in plasma. These findings indicate that BD-receptor preparations as used for the RRA are valuable tools to investigate binding affinities and pharmacokinetic properties of BD. Plasma levels of RRA active material may reflect a better correspondence to some clinical effects of BD than levels of the parent compound alone.

Pharmacokinetics of two partial benzodiazepine receptor agonistic beta-carboline derivatives in healthy volunteers.

Plasma levels of the two beta-carboline derivatives, ZK 91,296 (ethyl 5-benzyloxy-4-methoxymethyl-9H-pyrido (3,4-b) indole-3-carboxylate, CAS 83910-34-3) and ZK 95,962 (ethyl 5-isopropoxy-4-methoxymethyl-9H-pyrido (3,4-b) indole-3-carboxylate, CAS 101071-43-6) were measured in a total of 46 healthy male volunteers. The doses ranged from 1 to 40 micrograms/kg injected intravenously and from 40 to 600 mg given orally. Following i.v. injection, plasma levels declined in two phases with half-lives of 2-4 min (both drugs) and 0.5 h (ZK 95,962) or 1 h (ZK 91,296). The total clearance was 40-50 ml/min/kg and the oral bioavailability was estimated to be below 1% for both compounds. The reason was rapid first-pass inactivation, probably in the liver, and the formation of an acid metabolite. The plasma levels of this substance, which were determined after oral administration of ZK 91,296, were linearly correlated with the dose.

[The pharmacokinetics of lormetazepam following cimetidine]. / Die Pharmakokinetik von Lormetazepam nach Cimetidin.

Cimetidine delays the elimination from plasma of those benzodiazepines that are subject to oxidative drug metabolism. An open-label cross-over study was conducted to discover whether cimetidine also changes the plasma level profile of lormetazepam. METHODS. Ten volunteers (5 female, 5 male) took part in the study. After oral administration of 1 mg lormetazepam alone followed by a 6-day washout phase, the subjects received five 200-mg cimetidine tablets at intervals of 6 h (Table 1). The subjects took another 1-mg dose of lormetazepam p.o. together with the last tablet of cimetidine. Blood was sampled at specified intervals after both lormetazepam administrations, and the concentration of the drug in the plasma was determined by means of a specific radioimmunoassay. RESULTS. Cimetidine had no influence on the plasma levels of lormetazepam (Fig. 1). The drug concentrations increased quickly after both treatments regardless of sex and reached their highest values 1-2 h after oral ingestion. half-lives of 30-40 min were determined for the beta-phase and 8-10 h for the terminal elimination phase (Table 2). DISCUSSION. Lormetazepam, over 90% of which is excreted in humans as lormetazepam glucuronide, like oxazepam and lorazepam, does not obviously interact with cimetidine. All other benzodiazepines, which have to undergo oxidation before excretion, interact with drugs that inhibit the microsomal (cytochrome-P-450-dependent) enzyme system. CONCLUSION. In this study, no influence of simultaneous administration of cimetidine--a well-known inhibitor of P-450 dependent drug metabolism--on the pharmacokinetics of lormetazepam in either men or women was observed. This is in agreement with theoretical considerations: due to a 3-hydroxy group, lormetazepam does not require oxidation (hydroxylation) before it is metabolized into a water-soluble form capable of being excreted from the body. Cimetidine is therefore unlikely to potentiate the sedative effect of lormetazepam.