TABLE 2

Assessment of desloratadine as an inhibitor of P450 enzymes in pooled human liver microsomes (HLM)

P450 EnzymeSubstrate (Concentration)Inhibition by 10 μM Desloratadine (% Activity Remaining)
Direct inhibition (Zero-min Preincubation)TDI (30 min preincubation −NADPH)MDI (30 min preincubation +NADPH)Barecki et al., 2001a
CYP1A2Phenacetin (40 μM)96.380.393.2110b
CYP2B6Bupropion (50 μM)51.859.559.6N.D.
CYP2C8Paclitaxel (5 μM)98.9117100
CYP2C9Diclofenac (6 μM)94.1103106106
CYP2C19S-Mephenytoin (40 μM)89.391.987.2112
CYP2D6Dextromethorphan (7.5 μM)68.467.078.186.3
CYP3A4/5Midazolam (3 μM)55.756.155.084.0c, 80.0d
  • a Only direct inhibition (0-min preincubation) was evaluated.

  • b Substrate used was 7-exthoxyresorufin.

  • c Substrate used was dextromethorphan.

  • d Substrate used was testosterone.

  • N.D., no data.