Doxepin and the enzyme CYP2D6
Doxepin is processed to a large extent by the enzyme CYP2D6.
Initially, doxepin is metabolised (demethylated) by the enzyme CYP2C19 into another active substance. The enzymes CYP1A2, CYP2C9 and CYP3A4 are also involved in this step to a lesser extent. After this activation step this substance is metabolised further (hydroxylated) by the enzyme CYP2D6 into less active components.
The activity of the enzymes concerned can vary considerably depending on your genetic predisposition, which means the efficacy of doxepin can also differ from person to person.
Information about your genetic predisposition may therefore provide grounds for extra vigilance in relation to a treatment with doxepin.
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