The pharmacokinetic basis of alfentanil infusion.

Owing to the rapid blood:brain equilibration and the short duration of action, alfentanil is well suited for use in infusion techniques. A pharmacokinetic basis is given for alfentanil infusion schemes in patients undergoing routine surgery. Practical schemes can be worked out according to the general principle of a loading dose followed by a maintenance infusion. The loading dose of 100 micrograms kg-1 may be given as a short infusion, as two incremental doses, or as a combination of a single dose and short infusion. The maintenance infusion rate of approximately 1 microgram kg-1 min-1 results in steady-state plasma levels in the therapeutic range in most patients. Application of small extra doses, in addition to the maintenance infusion and modification of the infusion rate, might result in an appropriate and safe anaesthetic technique in most patients and surgical situations.