Benzodiazepines 4- Anaesthetics, local

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.)... 

Adverse effects. In addition to those given above, benzodiazepines can affect memory and balance. Hazards with car driving or operating any machinery can arise from amnesia and impaired psychomotor function, in addition to sleepiness (warn the patient). Amnesia for events subsequent to administration occurs with i.v. high doses, for endoscopy, dental surgery (with local anaesthetic), cardioversion, and in these situations it can be regarded as a blessing. ... 

There is one case report of kava kava potentiating the effect of benzodiazepines (see Benzodiazepines + Kava , p.730), and it has been suggested that it could potentiate other CNS depressants including barbiturates (e.g. thiopental), and may prolong or potentiate the effects of anaesthetics.Kava may act via GABA receptors, and kavalactones (one group of active constituents) also have skeletal muscle relaxant and local anaesthetic properties. Toxic doses can produce muscle weakness and paralysis. ... 

Kava pyrones are potent, centrally acting skeletal muscle relaxants. They act as hypnotics, antipyretics, sedatives, local anaesthetics, smooth muscle relaxants and antifungal agents. No interaction with benzodiazepine drugs or with moderate consumption of alcohol occurs, nor does kava impair mental alermess. However, continually chewing the root can destroy tooth enamel and eventually becomes habit forming (Bone 1994). 

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