CYP1A2 inhibition
A variety of medications and environmental factors may inhibit CYP1A2.
Medications. Medications that may inhibit CYP1A2 include atazanavir, ciprofloxacin, ethinyl estradiol, and fluvoxamine.3
Caffeine. A significant increase in caffeine consumption can result in inhibition.3 Among non-tobacco smokers, an increase of 1 cup/d of coffee or 2 cans/d of caffeinated soda would be considered significant.3 However, tobacco smokers would require an increase of 3 cups/d of coffee or 6 cans/d of soda.
Diet. An increase in the daily dietary intake of certain vegetables for 6 days has been shown to result in inhibition.10 Apiaceous (Apiaceae or Umbelliferae) vegetables such as carrots (3/4 cup), celery (1/2 cup), dill (1 teaspoon), parsley (3 tablespoons), and parsnips (1¼ cup) can decrease CYP1A2 activity by approximately 13% to 25%. Allium (Liliaceae) vegetables, such as garlic, leeks, and onions, have no effect on CYP1A2 activity.
Infection. Pneumonia, upper respiratory infections with fever, pyelonephritis or appendicitis, or inflammation are suspected to decrease CYP1A2 activity.8
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