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1085Re: [METHADONIA ] grapefruit juice and methadone

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  • James
    Jan 15, 2004
      Now there Ms.ssv55 this is indeed some wonderfull news
      if it's true,I thank you for the 'post of the month'
      and will give a follow up Sunday and tell all if
      indeed this "white grapefruit " advice did in fact
      work on me !
      Thanks,
      Jim/friendlyfarmer2001

      --- ssv55@... wrote:
      > Hello Dann and RG,
      > White grapefruit juice also affects drug metabolism.
      > Some patients
      > have had
      > good results potentiating an inadequate dose by
      > drinking 8 ozs. of
      > WHITE
      > grapefruit juice when dosing. �I found this info at
      > the following
      > URL:
      >
      > http://www.vhpharmsci.com/document/Article22.htm
      >
      > When ingested together, grapefruit juice can
      > interact with various
      > medications, resulting in potentially toxic drug
      > levels and
      > adverse effects.
      >
      > Certain bioflavonoids contained in citrus juices can
      > affect drug
      > metabolism.
      > The major bioflavonoid in grapefruit juice is
      > naringin, which is
      > partially metabolized
      > by enteral bacteria to form naringenin.1,2
      > Naringenin is a potent
      > inhibitor of the
      > cytochrome p450 liver enzymes: CYP1A2, CYP3A3 and
      > CYP3A4. There is
      > however,considerable inter-individual variability in
      > the effects of
      > grapefruit juice on
      > drug metabolism, in part due to :
      > 1) amount of naringenin formed by an individual,
      > 2) amount of naringin present in a brand of
      > grapefruit juice,
      > 3) dilution of grapefruit juice used, and
      > 4) other substances in grapefruit juice accounting
      > for the
      > interaction.
      >
      > Table 4 lists drugs whose levels may significantly
      > increase if given
      > concomitantly with grapefruit juice. CSU
      > Pharmaceutical Sciences will
      > place a label
      > stating "Do not take with grapefruit juice" if a
      > patient is ordered
      > any drug listed
      > below.
      >
      > Table 4. Grapefruit Juice-Drug Interactions
      >
      > Drug
      > � � � � � � � � � � � � � �
      > � � � � � �
      > Dihydropyridine Calcium Channel Blockers:
      > -amlodipine�
      > -felodipine
      > -nicardipine
      > -nifedipine�
      > AVOID grapefruit juice OR monitor for decreased BP,
      > increased HR if
      > taken together
      >
      > Terfenadine
      > AVOID grapefruit juice as may result in
      > cardiotoxicity (prolonged QT
      > interval)
      >
      > Cyclosporine�
      > �AVOID grapefruit juice, unless prescribed to
      > specifically
      > increase cyclosporine levels
      >
      > HMG-CoA Reductase Inhibitors (Statins)�:
      > -atorvastatin
      > -cerivastatin
      > -lovastatin
      > -simvastatin�
      > AVOID grapefruit juice as potential for myopathy or
      > rhabdomyolysis�
      >
      > Cisapride�
      > �AVOID grapefruit juice as potential for
      > cardiotoxicity (torsades
      > de pointes, prolonged
      > QT interval)�
      >
      > Benzodiazepines
      > -triazolam
      > -oral midazolam�
      > AVOID grapefruit juice or monitor for increased
      > sedation if used
      > together
      >
      > Quinidine�
      > AVOID; significance unknown
      >
      > Saquinavir
      > AVOID; signficance unknown
      >
      > Estrogens
      > -ethinyl estradiol�
      > -17� estradiol
      > AVOID - significance unknown
      > ====================================================
      > ====================================================
      >  http://www.atforum.com/pages/current_pastissues
      > /Vol6s97.html#anchor649123
      >
      >
      >
      >
      >
      >
      >
      > OTC Drugs, Juice, Vitamins
      > John St. Peter, PharmD, BCPS - Pharmacist in Charge
      > for HFA, and
      > Assistant Professor,
      > College of Pharmacy at the University of Minnesota -
      > has previously
      > expressed
      > concern in Addiction Treatment Forum (Vol. IV, #2)
      > about the
      > potential interactions of
      > methadone with OTC medications, tobacco, and
      > caffeine. He noted, for
      > example, that
      > acetaminophen (e.g., Excedrin�, Tylenol�) has
      > inherent
      > toxicities which can affect
      > hepatic drug metabolism and impact methadone blood
      > levels.
      > St. Peter and his clinical team have also observed
      > that there are
      > drug metabolism
      > differences between ethnic groups, such as Asians,
      > Caucasians, and
      > African-
      > Americans. Age also plays a role affecting changes
      > in drug
      > metabolism. Other sources
      > have noted that some persons are naturally "aberrant
      > metabolizers"
      > and "burn away"
      > methadone up to four times faster than others. The
      > specific roles of
      > these differences
      > regarding methadone metabolism, however, are still
      > under
      > investigation by the HFA
      > team.
      > There has been some mention, often anecdotally, of
      > grapefruit juice
      > intensifying
      > methadone's effects when the two are regularly taken
      > together.
      > According to
      > Andersen and Payte, grapefruit juice appears to
      > inhibit certain
      > enzymes (CYP-450
      > activity) that metabolize methadone in the liver,
      > thus slowing its
      > breakdown. Hence,
      > higher blood plasma levels of methadone than
      > expected might possibly
      > result. Some
      > sources have attributed naturally high
      > concentrations of flavonoids
      > in grapefruit juice
      > as producing this effect.
      > Contrary to current myth, there is no accepted
      > evidence that orange
      > juice produces
      > similar potentiating effects. However, Payte
      > mentions that large
      > doses of vitamin C
      > (the amount might vary by individual) could create a
      > more acidic
      > urine leading to
      > decreased methadone blood levels. This is because
      > the acidic
      > condition inhibits
      > reabsorption of methadone by the kidneys, so more of
      > the drug is lost
      > in the urine.
      > The plasma half-life of methadone could be reduced
      > to as little as
      > 16-20 hours in an
      > acid urine. Conversely, in an alkaline urine (pH
      > 7.8) a half-life of
      > 42.1 +/- 8.8 hours
      > has been reported
      > ====================================================
      >
      > I have also read that Tagament can increase the
      > blood concentration
      > of methadone,
      >
      === message truncated ===


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