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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Beagles, implanted with cortical and subcortical electrodes, were given etomidate i.v. (1 mg/kg) over a period of 10 sec. The effects on the EEG were compared with those obtained with 7 mg/kg of methohexital. Both compounds induced hypnosis for a duration of approximately 8 min. The EEGs showed a remarkable similarity. Visual inspection of the records as well as power spectrum analysis revealed a sustained theta-activity with underlying fast activity. The configuration of the waves was rather sharp. The power obtained after etomidate was, however, 2 to 3 times that obtained after methohexital. When the animals awoke from etomidate-induced hypnosis slow waves appeared and were followed by alpha-activity, whereas after methohexital-hypnosis beta-activity predominated. Etomidate slightly increased heart rate, but respiratory depression was not observed. Methohexital caused pronounced tachycardia and apnoea. In 3 out of 6 dogs methohexital caused myoclonus of the hind legs upon awakening from anaesthesia. Etomidate induced myoclonus in one dog during hypnosis.
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PMID:Electroencephalographic study of the short-acting hypnotics etomidate and methohexital in dogs. 63 Nov 87

Methohexital is an ultrashort-acting barbiturate widely used in dentistry because of its rapid onset, predictable effects, and short duration of action. Like other barbiturates, methohexital exerts its effects through the gamma-aminobutyric acid (GABA) receptor complex. By binding to its own receptor on the complex, methohexital augments the inhibitory effect of GABA on neurons and additionally can exert a similar effect independent of GABA. After intravenous injection, maximal brain concentrations are achieved within 30 sec and then quickly fall as the drug is redistributed to other tissues, yielding a duration of action after a single dose of 4 to 7 min. Hepatic metabolism accounts for elimination of the drug. Methohexital at conventional doses in healthy individuals is a mild respiratory depressant with modest cardiovascular effects. Adverse effects, however, can include apnea, cardiovascular depression, laryngospasm, hiccough, and allergic-like reactions. Although more recently introduced drugs, such as midazolam, etomidate, and propofol, have specific advantages, methohexital remains a drug of choice for dental outpatient anesthesia because of its low cost, rapid onset, short duration, lack of secretory or emetic properties, and proven history.
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PMID:Methohexital: a practical review for outpatient dental anesthesia. 184 56

The cardiovascular effects, anesthetic effects, and recovery rates were evaluated in racing Greyhounds under barbiturate anesthesia. Greyhounds and mixed-breed dogs of similar body weights were given (by IV route) thiopental (15 mg/kg), thiamylal (15 mg/kg), methohexital (10 mg/kg), and pentobarbital (20 mg/kg). The anesthesia lasted longer in Greyhound than in non-Greyhound mixed-breed dogs given thiopental, thiamylal, and methohexital. The mean times from recumbency to standing were 3 to 4 times longer for Greyhounds anesthetized with thiobarbiturates than for non-Greyhound mixed-breed dogs anesthetized with the same drugs, with recovery times for some Greyhounds lasting more than 8 hours. With thiobarbiturate anesthesia, Greyhounds had long periods of respiratory depression, struggled, and relapsed into sleep, whereas in the other dogs, the recovery was quiet. Respiratory depression related to the stage of anesthesia was produced by all barbiturates, but did not result in significant changes in blood gas values. Rectal temperature decreased in all dogs, but did not result in significant hypothermia. Cardiovascular variables and acid-base estimations in Greyhounds were not significantly different from those in mixed-breed dogs before and during barbiturate anesthesia. Packed cell volumes in Greyhounds were significantly higher than those in non-Greyhound mixed-breed dogs after the thiobarbiturates and methohexital were administered. Total plasma protein concentrations were significantly lower in Greyhounds, compared with those in the other dogs before and during barbiturate anesthesia. Methohexital is a useful alternative to thiobarbiturates for short-duration barbiturate anesthesia in Greyhounds.
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PMID:Barbiturate anesthesia in greyhound and mixed-breed dogs: comparative cardiopulmonary effects, anesthetic effects, and recovery rates. 377 30

Using a dual-isohypercapnic technique, the authors determined the effect of equipotent doses of methohexital (1.5 mg/kg) and etomidate (0.3 mg/kg) on the ventilatory response to CO2 (VERCO2) in six healthy volunteers. Speed of induction and duration of hypnosis did not differ significantly between the two drugs. Within 2 min after injection, the slope of VERCO2 decreased significantly after both methohexital (from 2.52 to a minimum of 0.15 l . min-1 . mmHg-1, P less than 0.05) and etomidate (from 2.56 to a minimum of 0.62 l . min-1 . mmHg-1, P less than 0.05); the magnitude of this depression did not differ significantly between the drugs. Methohexital also caused a significant decrease in minute ventilation at end-tidal PCO2 of 46 mmHg (VE 46) from 14.6 to 4.3 l . min-1 within 60 s after injection (P less than 0.05). In contrast, after etomidate VE 46 gradually increased from 17.9 1 . min-1 to a maximum of 31.6 l . min-1 at 3.5 min after injection (P less than 0.05); respiratory rate increased significantly, while changes in tidal volume were not significant. Effects of etomidate and methohexital on VE 46 differed significantly (P less than 0.001). These data indicate that, while etomidate and methohexital similarly depress the medullary centers that modify ventilatory drive in response to changing CO2 tensions, ventilation at any given CO2 tension is greater after etomidate than after methohexital. This indicates that etomidate may cause a CO2-independent stimulation of ventilation, suggesting its use for induction of anesthesia in cases where maintenance of spontaneous ventilation is desirable.
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PMID:Comparison of the ventilatory effects of etomidate and methohexital. 392 Sep 32

Rectal application of methohexital for induction of anaesthesia takes into consideration the child's psychological state. However, quite a lot of side effects may occur that are not dependent on age or body weight but on dosage. A clinical study with 66 children from nine months to seven years of age was performed to find out the most adequate dose of methohexital for rectal application. Three groups of children were given, 20, 25 and 30 mg methohexital/kg BW, respectively. Results obtained suggest 25 mg methohexital/kg BW to be the most adequate dose. Failure of induction was seen in 6%. Side effects like respiratory depression, excitation and unexpectedly high plasma levels of methohexital should be considered possible. Methohexital plasma levels of more than 22 micrograms/ml were obtained. Correlation between the effect and side effects of methohexital on the one hand, and maximal plasma levels on the other, were not seen. Since rectal application of methohexital in fact means induction of anaesthesia it should be given only in the presence of an anaesthesiologist and adequate anaesthesia equipment.
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PMID:[Rectal methohexital--anesthesia induction of choice in children?]. 409 Dec 38

The mechanism(s) of action of anesthetics on cell membrane ionic currents are not known. To investigate this further the effects of clinically relevant concentrations of ketamine, methohexital, and propofol on the delayed rectifier (IK) and the inward rectifier (IK1) currents of single dispersed guinea pig ventricular myocytes were studied. These voltage-gated currents are major components of cardiac cell electrophysiologic function regulating resting potential and repolarization. Each of the three anesthetics had a distinct spectrum of activity. Ketamine (10(-4) M) decreased IK1 (P < 0.05) but had no effect on IK. Methohexital (10(-4) M) had no significant effect on either current. Propofol (2.8 x 10(-5) M) resulted in significant depression of IK (P < 0.001) but had no effect on IK1. These results suggest that these intravenous anesthetics may have more specific effects on sarcolemma than volatile anesthetics, whose effects may be more generalized membrane effects.
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PMID:Distinctive effects of three intravenous anesthetics on the inward rectifier (IK1) and the delayed rectifier (IK) potassium currents in myocardium: implications for the mechanism of action. 841 22

Electroconvulsive therapy is being used more frequently in the treatment of many chronic and acute psychiatric illnesses in children. The most common psychiatric indications for pediatric electroconvulsive therapy are refractory depression, bipolar disorder, schizophrenia, catatonia, and autism. In addition, a relatively new indication is the treatment of pediatric refractory status epilepticus. The anesthesiologist may be called upon to assist in the care of this challenging and vulnerable patient population. Unique factors for pediatric electroconvulsive therapy include the potential need for preoperative anxiolytic and inhalational induction of anesthesia, which must be weighed against the detrimental effects of anesthetic agents on the evoked seizure quality required for a successful treatment. Dexmedetomidine is likely the most appropriate preoperative anxiolytic as oral benzodiazepines are relatively contraindicated. Methohexital, though becoming less available at many institutions, remains the gold standard for induction of anesthesia for pediatric electroconvulsive therapy though ketamine, propofol, and sevoflurane are becoming increasingly viable options. Proper planning and communication between the multidisciplinary teams involved in the care of children presenting for electroconvulsive therapy treatments is vital to mitigating risks and achieving the greatest therapeutic benefit.
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PMID:Anesthetic considerations for pediatric electroconvulsive therapy. 2821 Dec 48