The use of flunitrazepam (Rohypnol) in paediatric plastic surgery

The efficacy of flunitrazepam, a sedative and hypnotic agent, in facilitating minor procedures in plastic surgery was assessed in 25 children. The drug was administered in a dose of 0.030 mg/kg body weight. Adequate sedation was achieved with minimal side effects. The respiratory rate and the blood pressure showed minimal change whereas the pulse rate was unaltered.

Evidence for the existence of several different alpha- and beta-subunits of the GABA/benzodiazepine receptor complex from rat brain

gamma-Aminobutyric acid (GABA)/benzodiazepine receptors purified from the brains of young and adult rats were photolabeled by [3H]flunitrazepam or [3H]muscimol. Gel electrophoresis revealed 3 different proteins with apparent molecular weight (Mr) 51,000, 53,000 and 59,000 which were specifically and irreversibly labeled by [3H]flunitrazepam and recognized by the alpha-subunit specific antibody bd-28. Similarly, 3 different proteins with Mrs 51,000, 53,000 and 56,000 were irreversibly labeled by [3H]muscimol and recognized by the beta-subunit-specific antibody bd-17. Comparison of the photolabeling and immunological staining pattern from young and adult rats seems to indicate that proteins labeled by [3H]flunitrazepam and bd-28 are different from those labeled by [3H]muscimol and bd-17.

[Comparison of blood pressure profiles with flunitrazepam/fentanyl/nitrous oxide vs cervical epidural anesthesia in surgery of the carotid artery]

A study was carried out to compare the evolution of arterial blood pressure during carotid endarterectomy performed under either general anaesthesia (GA) or cervical epidural anaesthesia (CEA). 20 patients were randomly assigned to two equal groups. In the CEA group, 15 ml of 0.375% bupivacaine and 150 micrograms fentanyl were injected into the epidural space at C7-D1 level. In the GA group, patients were anaesthetized with 0.2 mg.kg-1 flunitrazepam and 5 micrograms.kg-1 fentanyl; intubation was carried out using 0.08 mg.kg-1 vecuronium, and the patients were ventilated with a mixture of nitrous oxide and oxygen (50% of each). Further injections, every 30 min, of 2 micrograms.kg-1 fentanyl were given to the patients in group GA. Blood pressure was monitored continuously, up to 4 h postoperatively, with a radial arterial catheter. Per- or postoperative hypertension was defined as a rise in systolic arterial blood pressure (Pasys) over 180 mmHg for greater than 3 min; this was treated with 20 mg nifedipine intranasally (group CEA) or 100 micrograms fentanyl with 0.5 mg flunitrazepam with or without nifedipine (group GA). Per- or postoperative hypotension was defined as a fall in Pasys below 100 mmHg and or a 30% fall in mean arterial blood pressure for greater than 3 min; this was treated, in both groups, with an intravenous bolus of 3 mg ephedrine. Patients in group CEA experienced more frequent episodes of peroperative hypertension (8/2; p less than 0.02) and postoperative hypotension (5/1) than group GA.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies directed against a nonapeptide sequence of the gamma-aminobutyrate (GABA)/benzodiazepine receptor alpha-subunit. Detection of a distinct alpha-like subunit in pig cerebral cortex but not cerebellum

A synthetic peptide, corresponding to amino acid residues 101-109 of the bovine gamma-aminobutyrate/benzodiazepine receptor alpha-subunit, was used to raise a polyclonal antiserum. The reactivity of this antiserum towards polypeptides of both bovine and pig receptor preparations was established by immunoprecipitation and immunoblotting. Anti-peptide antibodies recognized the alpha-subunit (51 kDa) of receptor prepared from pig cerebellum or cerebral cortex. However, a polypeptide of 57 kDa was additionally recognized in cortical, but not cerebellar, preparations. This alpha-like polypeptide appeared larger than the band of polypeptides labelled irreversibly with [3H]muscimol (beta-subunit, 55-57 kDa) and corresponds to a polypeptide detected only in cortex after silver-staining or irreversible labelling with [3H]flunitrazepam. These results support the idea that the distinct regional patterns of polypeptides labelled irreversibly with [3H]flunitrazepam reflect the existence of heterologous distributions of distinct alpha-like subunits.

Modification of the apparent molecular weight of different benzodiazepine binding proteins from rat brain membranes by various endoglycosidases

Membranes from rat cerebellum or hippocampus were photolabeled by [3H]flunitrazepam and incubated with various endoglycosidases. The largest reduction in apparent molecular weight of photolabeled proteins P51 (mol. wt. 51,000) and P55 (mol. wt. 55,000) was obtained using endoglycosidase F or glycopeptidase F. However, even after extensive treatment with these enzymes the deglycosylated products of proteins P51 (apparent mol. wt. 44,000) and P55 (two peptides with apparent mol. wt. 48,000 and 51,000) still differed in their apparent molecular weight. This might indicate that structural features other than N-linked carbohydrates are responsible for the difference in apparent molecular weight of these proteins.

[Effect of fentanyl and enflurane on sensory evoked potentials in the human in basic flunitrazepam/N2O anesthesia]

The use of evoked potential recording is commonly employed for monitoring peripheral and central sensory functions during neurosurgical procedures. However, the neuronal structures studied must not be changed by the anesthetic agents used. In this connection, the influence of two anesthetics, fentanyl and enflurane, on evoked potentials was investigated under basic anesthesia. A total of 60 patients undergoing lumbar disc removal were included in the study. Somatosensory (SEP), auditory (AEP), and visual (VEP) evoked potentials were each recorded in 20 patients the day before operation. Basic anesthesia was induced with flunitrazepam, nitrous oxide, and pancuronium bromide. Following induction, recordings of evoked potentials were again made. One half of each group of 20 patients received increasing doses of fentanyl (1.8, 3.6, and 7.2 micrograms/kg in the somatosensory and auditory groups; 4.0 and 8.0 micrograms/kg in the visual group). The other half was given increasing inspiratory concentrations of enflurane (0.5, 1.0, and 1.5 vol.%). At each level of anesthesia, SEPs, AEPs or VEPs were recorded. As compared with preoperative recordings, post-stimulus latencies were virtually unaffected by the basic anesthesia. Fentanyl caused little increase in the latencies of middle-latency-SEPs and of peak P2 of the VEPs. With enflurane, however, the latencies of the SEPs were dose-dependently prolonged, in particular those of the later components (P25 to N55). The same was true for the peak P2 in the VEPs. AEPs were not changed at all. From the results it can be concluded that enflurane, but not fentanyl, impairs impulse conduction in central synaptic pathways.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of increasing amounts of epinephrine during isobaric bupivacaine spinal anesthesia in elderly patients

The effects of adding epinephrine to isobaric bupivacaine spinal anesthesia were investigated in 96 ASA class II-III patients aged 75 yr or more scheduled for lower extremity surgery. The subjects were randomly allocated into six groups. All patients received 15 mg bupivacaine plain solution in 4 ml, in the horizontal position. Patients in group 1 received bupivacaine plus 1 ml normal saline; patients in other groups received bupivacaine plus increasing dosages of epinephrine: 0.1 mg (group 2), 0.2 mg (group 3), 0.3 mg (group 4), 0.4 mg (group 5), 0.5 mg (group 6). The segmental level of sensory loss was tested using forceps. The time required for maximal spread of the sensory blockade was significantly 50% greater in group 5 than in group 1. No difference was observed, however, between mean highest levels. Addition of 0.2 mg epinephrine prolonged by a significant 25% regression time to L-2 level. Addition of 0.3 and 0.4 mg epinephrine significantly prolonged two-segment regression time by 36 and 53%, respectively, and regression to L-2 level by 29 and 44%, respectively. Addition of 0.5 mg epinephrine did not result in further prolongation of anesthesia. Motor blockade was also increased by addition of epinephrine. It is concluded that addition of 0.3 mg epinephrine may be useful to increase duration of isobaric bupivacaine spinal anesthesia.

[The use of DSIP (delta sleep-inducing peptide) in the correction of phase-shifted insomnia]

A 47-year old woman patient suffering from chronic delayed sleep phase insomnia and low-dose benzodiazepine dependence was treated as an inpatient under close polygraphic control using DSIP (delta sleep inducing peptide) on an intensive-care basis for one week. This treatment resulted in advancing the main sleep phase by 5 hours, in an abrupt and complete withdrawal of flunitrazepam and restitution of a normal sleep profile. Actographic control during an after treatment week confirmed that the success was maintained.

Benzodiazepine receptors in the human cerebellar cortex: a quantitative autoradiographic and pharmacological study demonstrating the predominance of type I receptors

The anatomical localization of benzodiazepine receptors in the human cerebellar cortex was studied using quantitative autoradiography following in vitro labelling of cryostat sections with [3H]flunitrazepam ([3H]FNZ), and the pharmacology of these receptors has been characterized by computerized, non-linear least squares regression analysis of [3H]FNZ displacement by FNZ, CL218,872 and ethyl beta-carboline-3-carboxylate (ECC) binding to membranes. The autoradiograms demonstrated that benzodiazepine receptors were present throughout all layers of the human cerebellar cortex; high concentrations of receptors were present in the molecular layer, moderate concentrations were present in the granular layer and a much lower density of receptors was seen in the intervening Purkinje cell layer. The pharmacological studies indicated that the human cerebellar cortex contained a high concentration of homogeneous benzodiazepine receptors which have high affinity for FNZ, ECC and CL218,872, i.e. type I sites.

[Ro 15-1788 antagonizes reliably the Benzodiazepine effect after Flunitrazepam combination anesthesias]

INTRODUCTION

The imidazobenzodiazepine Ro 15-1788 has been shown to block the central effects of benzodiazepines without severe side effects in animals studies and human volunteers. Benzodiazepine premedication and benzodiazepine/opioid combinations are often used in anesthesiology. A prolonged benzodiazepine action in combination with narcotics can cause problems in the postoperative period such as respiratory depression or aspiration of gastric contents due to reduced vigilance. Therefore, a reversal of the central effects of benzodiazepines can be of advantage postoperatively. This study was designed to compare the efficacy of Ro 15-1788 and placebo in reversing the central effects of flunitrazepam used to induce and maintain general anesthesia.

METHODS

STUDY DESIGN

double blind, parallel groups, randomized, placebo-controlled study. 60 patients of both sexes aged 20-65 years, ASA class I-II, who were to undergo elective surgery under general anesthesia with an estimated duration of 90-150 min. Study procedure: Evening premedication: 1-2 mg flunitrazepam orally. Morning premedication: 7.5 mg midazolam orally. Monitoring: blood pressure, heart rate, and ECG continuously. Induction of anesthesia: 0.2 mg fentanyl, 0.03-0.04 mg/kg flunitrazepam, 0.1 mg/kg pancuronium. Endotracheal intubation, mechanical ventilation. Maintenance of anesthesia: N2O/O2 = 2:1, fentanyl, pancuronium, and flunitrazepam depending on clinical response. At the end of surgery and after decurarization (neostigmine 2.5 mg and atropine 0.5 mg) and oxygenation the patients were extubated. Now Ro 15-1788 or placebo in a 5% glucose solution (in the case of Ro 15-1788: 1 ml = 0.1 mg active drug) were administered.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminophylline reversal of flunitrazepam sedation

Seventeen otherwise healthy patients were given either intravenous physiologic saline, 5 ml, or aminophylline, 2 mg/kg, randomly 30 min after they were given intravenous flunitrazepam in doses adequate to produce sleep and sedation during spinal anesthesia for anorectal surgery. In the control group, mean sedation scores were 1.8 +/- 0.3 and 1.0 +/- 0.4 15 and 45 min after injection of placebo. Fifteen and 45 min after the injection of aminophylline the mean scores of sedation were 0.4 +/- 0.2 and 0.2 +/- 0.2, respectively. Even though the patients in both groups appeared to be equally alert and responsive after 75 min, Trieger tests revealed that psychomotor function was still significantly impaired in the control group 90 min after the injection of placebo. The amnesic effects of flunitrazepam were not affected by aminophylline. Aminophylline may be used to reverse the sedative and psychomotor effects of flunitrazepam.

[Midazolam used for premedication reinforces sleep induced by flunitrazepam]

This single blind study aimed to discover possible effects of intramuscular premedication with midazolam on the sleep induced by intravenous flunitrazepam. 24 male patients, aged 17 to 71 years, who were to undergo surgery to the distal parts of an upper limb under regional anaesthesia, were randomly assigned to two equal groups: in the midazolam group, an intramuscular premedication of 0.12 mg.kg-1 midazolam with 0.5 mg atropine was given, whereas in the control group atropine only was used. In all patients, 1 mg flunitrazepam was given intravenously 45 min after the premedication, before carrying out regional anaesthesia. No other drug was given. In the midazolam group, the time of loss of spontaneous conversation was reduced (p less than 0.05), as well as the time of eye closure (p less than 0.001), and the time for recovery of the capacity to count backwards was increased (p less than 0.001). So, premedication with 0.12 mg.kg-1 midazolam intravenously 45 min before giving 1 mg flunitrazepam reinforced the sleep induced by the latter.

[Hemodynamic parameters and blood-free surgical field with nitroglycerin in maxillofacial surgery]

73 oral facial surgery have been performed using controlled-hypotension induced with nitroglycerin (NTG) to reduce surgical bleeding. Surgical bleeding has been reduced in more than 45% of cases. But frequent lack of correlation between blood pressure, heart beat and bleeding might imply vascular reflex mechanisms induced by controlled-hypotension using NTG. Hemodynamic parameters such as blood pressure and heart rate seem to be insufficient to monitor controlled hypotension efficiency on surgical bleeding. The use of peroperative tissues blood flow monitoring may help for the better understanding of surgical bleeding during controlled-hypotension using NTG.

[Ketamine/flunitrazepam--an alternative intravenous anesthesia]

In a controlled randomized study, 21 patients who received a combination of ketamine and flunitrazepam with relaxation and N2O/O2-ventilation were compared with 20 patients who received neuroleptic analgesia (NLA) for intra-abdominal surgery. The two groups of patients were comparable with respect to age, sex, type of surgery, time of operation and coexistent diseases. The dosage of ketamine chosen was a total of 0.92 mg/kg per hour. For maintenance of anaesthesia, only 0.5 mg/kg per hour was used. In combination with 0.7-1.0 mg flunitrazepam and N2O/O2 ventilation, this low dose of ketamine was satisfactory. Electroencephalographic and electromyographic recordings demonstrated and adequate level of anaesthesia. The determination of serum free fatty acid levels showed a well-balanced in stress. Occasional elevations of blood pressure--which also were seen in the NLA-group--were not overcome by increasing the ketamine dosage. A brief addition of enflurane or isoflurane was more effective. The immediate postoperative onset of spontaneous respiration without complications and with normal CO2 levels was remarkable. The method was well accepted by the anaesthetist responsible and the nursing personnel.

Benzodiazepine receptors in rat brain are altered by adrenalectomy

The effects of adrenalectomy on benzodiazepine receptors in discrete regions of rat brain were examined using [3H]flunitrazepam as binding ligand. The concentration of benzodiazepine receptors was significantly increased by 25, 50 and 71% in hippocampus, striatum and hypothalamus, respectively, after adrenalectomy. In contrast, adrenalectomy did not affect the concentration of benzodiazepine receptors in cerebral cortex, olfactory bulb and cerebellum. No significant differences in the apparent binding affinity (Kd) values were seen following adrenalectomy in any brain region examined. The adrenalectomy-induced increases in [3H]flunitrazepam binding sites were completely reversed by glucocorticoid replacement with dexamethasone. These results demonstrate that adrenalectomy is capable of selectively modulating benzodiazepine receptors in brain regions presumably involved with glucocorticoid negative feedback. The data further suggest additional mechanisms by which endogenous hypothalamic-pituitary-adrenocortical hormones may affect 'anxiety' levels.