Table 2.
Effect of the newer antidepressants in inhibiting the activity of various cytochrome P450 enzymes; based on in vivo studies. All values relate to the percentage reduction in CYP enzyme activity at the usual therapeutic dosage (adapted from [3, 4]).
| Enzyme | Citalopram | Fluoxetine | Fluvoxamine | Paroxetine | Sertraline | Mirtazapine | Nefazodone | Venlafaxine |
|---|---|---|---|---|---|---|---|---|
| CYP1A2 | −/+ | −/+ | − + + | −/+ | −/+ | − | − | − |
| CYP2C9/10 | ? | ? | ? | ? | + | ? | − | − |
| CYP2C19 | −/+ | + + | + + | ? | + | ? | − | − |
| CYP2D6 | + | + + + | + | + + + | + | + | − | − |
| CYP3A3/4 | ? | + + | + + | −/+ | −/+ | − | + + + | − |
Symbols: ? = unknown; – = no effect; + = < 50% change; + + = 50–150% change; + + + = > 150% change.