[The effect on breathing of flunitrazepam and benzoctamine as adjuvants in spinal anesthesia in broncho-pulmonary risk patients]

The influence of intravenous Flunitrazepam (0.4-0.8 mg), Benzoctamine (10-20 mg) and Placebo (NaCl 0.9%) on pO2, pCO2, forced vital capacity, forced expiratory volume and peak flow were investigated in patients with reduced lung function undergoing orthopaedic surgery under spinal anaesthesia. Both drugs depress respiration: Flunitrazepam immediately, Benzoctamine about 15 min after administration. Both drugs reduce lung function in the postoperative period. They should be administered under careful observation of patients' respiration, administration of oxygen and only in special cases where sedation is necessary to reduce psychological stress. The advantage of regional anaesthesia in patients with high risk of postoperative pulmonary failure seems worth retaining compared to general anaesthesia.

Termination of anaesthesia--do we pay enough attention to its consequences? Haemodynamic studies following the use of piritramide, flunitrazepam and nitrous oxide anaesthesia for open heart surgery

After completion of coronary or valve replacement surgery the haemodynamic changes due to cessation of nitrous oxide were measured. Seventy-four patients received piritramide-nitrous oxide anaesthesia. In 20 patients nitrous oxide was continued after operation and no marked haemodynamic changes occurred. However, when nitrous oxide was discontinued immediately after the operation (n=30) a significant rise in systolic arterial pressure (108+/-15 to 153+/-30 mm Hg), systolic pulmonary artery pressure (35+/-9 to 40+/-16 mm Hg), systemic vascular resistance (111 +/-26 to 148+/-44 MN.s.m-5) and rate pressure product (9,600+/-1,600 to 14,300+/-4,000) occurred. Heart rate (89+/-11 min-1), left artrial pressure (13+/---4 mm Hg) CO2 minute production (125+/-19 ml. min-1.m-2) and cardiac index (2.5+/-0.61.min-1.m-2) rose only moderately. When additional flunisternal closure to 24 patients, marked haemodynamic changes were still noted after N2O withdrawal, even though anaesthesia was prolonged. The sudden rise of arterial pressure and vascular resistance implies risks to patients with myoicardial or coronary insufficiency, therefore close monitoring is necessary, when nitrous oxide has to be stopped, to enable undelayed antihypertensive therapy.

Flunitrazepam for the intravenous induction of anaesthesia in children

Flunitrazepam (Rohypnol) was compared with thiopentone as an anaesthetic induction agent in children between 4 and 12 years of age who underwent elective minor surgical procedures. Successful induction of anaesthesia was achieved in both groups of patients. With flunitrazepam the induction time was longer but not statistically different from that with thiopentone. The incidence of apnoea was higher with thiopentone, but not significantly so. It is concluded that flunitrazepam could prove a reasonable alternative to thiopentone as an intravenous induction agent in children who have to undergo elective minor operations.

[Flunitrazepam-pretreatment for prevention of adverse cardiovascular effects following ketamine]

In 18 patients with documented ischaemic heart disease the cardiovascular effects of ketamine (1.5 mg/kg iv) were studied under three different conditions: 1. in awake premedicated patients (n = 6); 2. after the previous administration of flunitrazepam (0.015 mg/kg iv, n = 6) and 3. under conditions of neuroleptanalgesia and muscle relaxation (n = 6). Flunitrazepam prevented or at least attenuated the increases in heart rate (30%), mean arterial pressure (37%), mean pulmonary artery pressure (165%), left ventricular filling pressure (230%), total peripheral resistance (50%), pulmonary vascular resistance (100%) and in the rate-pressure product (66%) which were associated with the use of ketamine as the sole anaesthetic agent. In addition, the flunitrazepam-pretreatment abolished the fall in cardiac index and stroke index which occured in patients given ketamine alone. Flunitrazepam therefore appears to be a promising drug to prevent adverse cardiovascular reactions, when ketamine should be chosen for induction of anaesthesia. Neuroleptanalgesia and muscle relaxation also proved effective in controlling the sympathomimetic actions of ketamine. The response of the mean pulmonary artery pressure and of the ventricular filling pressures to ketamine in this group was even more damped than in the patients pretreated with flunitrazepam alone.

Neuronal localisation of benzodiazepine receptors in cerebellum

The cellular localisation of benzodiazepine receptors was studied. Kainic acid induced neuronal lesions (2 x 0.25-2 x 2 micrograms; 2-26 days in rat cerebellum decreased specific binding of [3H]flunitrazepam down to 35% of controls. Specific binding of [3H]flunitrazepam was also decreased (to 80% of controls) in the cerebllum of mutant nervous mouse (nr/nr) where Purkinje cells are degenerated but in the mutant weaver mouse where granule cells are degenerated. These results show that benzodiazepine receptors are located mainly on neurons; both on Purkinje cells and other neurons, but not to a great extent on granule cells.

General anaesthesia with intravenous flunitrazepam, continuous ketamine infusion and muscle relaxant. A preliminary report

We present a preliminary report of an anaesthetic technique for abdominal surgery involving a combination of flunitrazepam induction and continuous ketamine maintenance of anaesthesia, specifically avoiding the use of any inhalational agents. Standard techniques of muscle relaxation, intubation and ventilation with oxygen-enriched air were employed.

[Respiratory depression after fentanyl and antagonism by naloxone (author's transl)]

The postoperative respiratory depressant effect of fentanyl in combination with flunitrazepam (Rohypnol) was assessed in awake and in unconscious patients. In awake patients respiratory function was measured with blood-gas analyses. For measurements in unconscious patients the administration of nitrous oxide/oxygen was continued postoperatively and the respiratory depression was judged from the increase in respiratory minute volume after the i.v. administration of 0.05 mg naloxone (Narcan). In the group of awake patients blood-gasvalues were within the normal range after anaesthesia with flunitrazepam (1 mg) and fentanyl (0.80 mcg/kg body weight/10 min anaesthesia; last fentanyl given 40 min before the end of the operation), and the administration of naloxone was without any effect. If, however, naloxone was given while the patients were kept under light nitrous oxide/oxygen anaesthesia, the effect was different. The respiratory minute volume was considerably less than its predicted value in all groups of patients having received fentanyl, and naloxone caused a marked increase in respiratory minute volume and in respiratory rate. In a group of patients which have received no opiate but enflurane, naloxone showed no effect. After premedication with pethidine as compared with flunitrazepam the effect of naloxone on ventilation was more pronounced. This marked difference in the postoperative effect of fentanyl on ventilation depending on the state of consciousness has to be attributed to an interaction between a residual respiratory depressant effect of fentanyl and the effect of unconsciousness. Since after the combined use of flunitrazepam and fentanyl deep postoperative sleep occurs quite frequent, a residual effect of fentanyl should always be antagonized with naloxone to protect the patients from a possible hazardous effect of this interaction.

Premedication with flunitrazepam in gastro-intestinal endoscopy

Administration of 2 mg flunitrazepam (Rohypnol; Roche) to patients before gastro-intestinal endoscopy caused significantly less anxiety and achieved significantly greater sedation than diazepam (Vallium; Roche). No differences were found between any of the trial groups with respect to ease of intubation, tolerance of the procedure, gastric peristalsis, and the state of the pylorus. Memory of the procedure was significantly less vivid in the groups who received 2 mg flunitrazepam, than in the other groups. The patients who received 2 mg flunitrazepam showed a significantly greater willingness to undergo a repeat procedure, both when asked immediately after the procedure, and when asked on the next visit. Pulse rate increased in all groups during the procedure. No change in respiratory rate or in systolic and diastolic blood pressure occurred in any group.

Anaesthetic induction and maintenance with flunitrazepam

Flunitrazepam (Rohypnol) was investigated as an intravenous induction agent for dental procedures in 15 patients in a private anaesthetic practice. During this study it was noted that the normal halothane requirement could be reduced substantially. A second study to investigate this new phenomenon was done on 50 patients who underwent major surgery. The results indicate that adequate anaesthesia can be maintained with flunitrazepam.

[Effect of combined application of halothane and some central depressants (author's transl)]

The combined effects of halothane and various central depressants were studied in mice by means of an isobolographic method which allows the statistical evaluation of interactions. A loss of the righting reflex for at least 2 min was taken as the criterion for the synchronisation of the peak time of drug effects. All interactions turned out to be supra-additive, more pronounced in the case of diazepam and flunitrazepam than in the case of medazepam, pentobarbitone or ethanol. The organic solvent used for the solution of diazepam and flunitrazepam was found to contribute to the observed interactions. The difficulties of estimating and classifying combined drug effects as well as their clinical relevance are discussed.