All About Gleevec (Glivec)
General Information |
Response Rate & Related Exon Mutations
Dosage |
Side Effects |
Drug Interactions
Drug Interactions
Other drugs affect Gleevec |
Gleevec affects other drugs
Long list of inhibitors and inducers |
Drug interaction glossary
Other drugs affect Gleevec drug concentrations
In addition to the intended affects, many drugs
have an effect on how quickly other drugs are
metabolized by the liver. This is one type of
drug interaction, but not the only type.
Gleevec is metabolized (broken down) by the
liver. The enzyme most responsible for this is
called CYP3A4 (one part of the "cytochrome P450"
family of liver enzymes). The next most
important enzyme for metabolizing Gleevec is
CYP2D6.
Drugs that
inhibit the activity/production of these two
enzymes (but especially CYP3A4) slow down the
metabolism of Gleevec. This results in a higher
concentration of Gleevec in the blood. The could
result in more side effects from Gleevec;
similar to taking a higher dose of Gleevec. This
would be more of a concern for patients already
taking a high dose of Gleevec especially if they
were already having significant Gleevec side
effects.
For patients on a lower dose of Gleevec that
were having few or no side effects, then taking
a drug that might "inhibit" CYP3A4 or CYP2D6
would probably have less effects, and perhaps
not even be noticed.
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Drugs that may alter Gleevec plasma concentrations NOTE: Sutent is also metabolized by CYP3A4 and is affected by drugs that induce or inhibit CYP3A4. (This is a "short list") |
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Major |
Major |
Reduce Gleevec levels |
Increase Gleevec levels |
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People also metabolize drugs at different rates. Given the vast amount of differences that can occur, it is critical to clinically monitor patients and adjust dosages of medicines as needed. This is a job for your doctor, but patients also need to keep their doctor informed of side effects. How you feel may be just as important as whether or not the drug you are taking appears on the CYP3A4 or CYP2D6 INHIBITOR lists.
A different situation exists when taking a drug
that could
INDUCE CYP3A4 or CYP2D6. In this case, the
drug might cause Gleevec to be metabolized
faster, possibility resulting in AN INEFFECTIVE
AMOUNT OF GLEEVEC IN THE BLOOD. In the worst
case scenario, you could stop responding to
Gleevec. The danger of this type of interaction
is probably higher for patients taking a lower
dose of Gleevec since they are closer to the
minimum therapeutic levels of Gleevec, and
taking a drug that increases Gleevec metabolism
might result in Gleevec levels being below the
minimum needed to keep GIST (or CML) under
control. Patients on higher doses of Gleevec are
not immune to this problem either, as at least
one drug, phenytoin, reduced plasma levels of
Gleevec by 75% in a CML patient.
Your body will be more likely to give you some
indication of a problem with the drugs on the
inhibitor list, due to an increase in side
effects. Drugs that induce CYP3A4 or CYP2D6 may
be less likely to produce side effects, since
they tend to lower the concentration of Gleevec
in the blood.
More information can be found at:
www.drug-interactions.com




