Interactions : אינטראקציות

4.5   Interaction with other medicinal products and other forms of interaction
Concentration of other gases
The MAC for desflurane is reduced by concomitant N2O administration (see Table 1).

Non-depolarizing and depolarizing muscle relaxants
Commonly used muscle relaxants are potentiated by desflurane.
Anaesthetic concentrations of desflurane at equilibrium reduce the ED95 of suxamethonium by approximately 30% and that of atracurium and pancuronium by approximately 50% compared to N2O/opioid anaesthesia. The doses of pancuronium, atracurium, suxamethonium and vecuronium needed to produce 95% (ED95) depression in neuromuscular transmission at different concentrations of desflurane are given in Table 2. With the exception of vecuronium, these doses are similar to isoflurane. The ED95 of vecuronium is 14% lower with desflurane than isoflurane. Additionally, recovery from neuromuscular blockade is longer with desflurane than with isoflurane.

Table 2: Dosage (mg/kg) of muscle relaxant causing 95% depression in neuromuscular transmission

Desflurane
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Concentration      Pancuronium       Atracurium      Suxamethonium        Vecuronium 0.65 MAC/             0.026              0.133            *NA                *NA 60% N2O/O2
1.25 MAC/               0.018             0.119              *NA               *NA 60% N2O/O2
1.25 MAC/O2             0.022             0.120              0.362            0.019 100% O2
*NA = not available

Pre-anaesthetic Drugs
No clinically significant adverse interactions with commonly used pre-anaesthetic drugs, or drugs used during anaesthesia (intravenous agents, and local anaesthetic agents) were reported in clinical trials. The effect of desflurane on the disposition of other drugs has not been determined.
Sedatives
Patients anaesthetised with different concentrations of desflurane who received increasing doses of fentanyl showed a marked reduction in the anaesthetic requirements or MAC. The administration of increasing doses of intravenous midazolam showed a small reduction in MAC. Results are reported in Table 3. These MAC reductions are similar to those observed with isoflurane. It is anticipated that there will be a similar influence on MAC with other opioid and sedative drugs.



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Table 3: Effect of Fentanyl or Midazolam on Desflurane MAC
*MAC (%)              %MAC Reduction
No Fentanyl                       6.33 - 6.35                        - Fentanyl (3 mcg/kg)               3.12 - 3.46                    46 - 51 Fentanyl (6 mcg/kg)               2.25 - 2.97                    53 - 64 No Midazolam                      5.85 - 6.86                       - Midazolam (25 mcg/kg)                4.93                        15.7 Midazolam (50 mcg/kg)                4.88                        16.6 * Includes values for ages 18 - 65 years