This, initially the drug does not completely metabolize
and has an extended half-life. This why it is dangerous to take
grapefruit juice with certain medications. Follow me on this. You take a substance that reduces the production of these enzymes (say grapefruit juice) and for the first four hours the drug does not fully metabolize. After six hours the grapefruit juice wears off, the liver again starts producing these enzymes, and you take a second dose of the medication.