[Rectal administration of anesthetic agents].
OBJECTIVES: To collect data in the current literature dealing with the diffusion, the reliability and the effectiveness of the rectal administration of anaesthetic drugs. To evaluate differences with parenteral administration. DATA SOURCES: Pharmacokinetics and clinical studies published in recent years in indexed journals. STUDY SELECTION: Based on the study methodology, drugs employed and pharmacokinetic parameters evaluated. DATA EXTRACTION: Factors involved in absorption of drugs from the rectal mucosa, clinical effect and pharmacokinetic data of the following drugs: diazepam, flunitrazepam, midazolam, ketamin and methohexital, then a brief evaluation of other drugs: thiopental, etomidate, morphine and chloral hydrate. DATA SYNTHESIS: The most widely used drugs are benzodiazepines: they are safe, easy to manage and highly effective; among them midazolam has the best kinetic and dynamic pattern. Ketamin is useful during painful diagnostic procedures; with the use of barbiturates there is a greater risk of respiratory depression and more caution must be employed. CONCLUSIONS: Wide intervariability of rate of absorption, achievement of plasma levels and clinical effect is a relevant drawback of this technique, such to make it not preferable to the parenteral route, when both are feasible. It deserves, anyway, more consideration, and maintains its validity for the preparation of the paediatric patient to general anaesthesia.