A retrospective review of the use of alfentanil in a hospital palliative care setting

Alfentanil is becoming an alternative to diamorphine when parental opioids are required, especially in the presence of renal insufficiency. Its pharmacokinetic properties suggest that tolerance may be rapidly induced, whilst concomitant administration of drugs that interfere with the cytochrome P450 system may alter its metabolism. This retrospective audit looked at the use of subcutaneous alfentanil in a palliative care setting over a 21-month period. Forty-eight out of the 81 notes identified were available for analysis. Alfentanil was used for a median of 9 days (range 1-81) with median increase in dose of 80% (range 0-1125%). No significant correlation was found between duration of infusion and dose escalation. In addition no significant correlation was found between dose escalation and concomitant drugs that either inhibited or induced the P450 system. This is the first study to investigate the use of relatively long-term use of parenteral alfentanil. The results suggest that neither tolerance nor concomitant drug administration is of clinical significance in the dose escalation.