Benzodiazepines 4- Anaesthetics, general

For reports of enhanced sedation when propofol is given with midazolam, thiopental or other anaesthetics, see Anaesthetics, general + Benzodiazepines , p.96. 

Setting aside the general anaesthetics, which do not directly modify the function of any particular neurotransmitter, all the drugs that are used to induce sleep, i.e. the hypnotics , augment the function of GABA and so directly depress neuronal function and probably facilitate cortico-thalamic synchrony. Most of them are benzodiazepines... 

Drugs that stimulate respiration (analeptics) have a place in anaesthetic practice but are not a substitute for mechanical ventilation. They have a direct effect on respiratory drive they do not share a common molecular structure. Respiratory stimulation is generally better achieved by antagonising the depressant effects of the depressant drug, e.g. flumazenil for benzodiazepines naloxone for opioids. 

Sedation and amnesia without analgesia are provided by midazolam i.v. or, less commonly nowadays, diazepam. These drugs can be used alone for procedures causing mild discomfort, e.g. endoscopy, and with a local anaesthetic where more pain is expected, e.g., removal of impacted wisdom teeth. Benzodiazepines produce anterograde, but not retrograde, amnesia. By definition, the sedated patient remains responsive and cooperative. (For a general account of benzodiazepines and the competitive antagonist flumazenil, see Ch. 19.)... 

Resumption of car driving or other skilled activity after anaesthesia is a special case, and an extremely variable one, but where a sedative (e.g. i.v. benzodiazepine, opioid or neuroleptic), or any general anaesthetic has been used it seems reasonable not to drive for 24 h at least. 

The interactions between propofol or thiopental and midazolam are well established. This synergy has been utilised for the induction of anaesthesia. Midazolam also reduces the dose requirements of halothane. Other benzodiazepines may also potentiate the effects of general anaesthetics. 

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