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1127Re: [METHADONIA ] grapefruit juice and methadone

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  • gertrude gandala
    Feb 25, 2004
    • 0 Attachment
      I guess

      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,
      however, I cannot find any documentation at this moment.
      Take care,
      Stephanie
      NY NAMA
      http://www.methadone.org
      ssv55@...
      Together We Can Make a Difference

      --- In DOLOPHINEA_CAFE@yahoogroups.com, "Dann White" <dannw87@e...>
      wrote:

      > I've heard a million rumors and I don't put a lot of stock in
      addict chemistry, my
      wife read in a pamphlet that drinking grapefruit juice (in her case,
      Tropicana Ruby
      Red) with your dose makes it climb on quicker. By the way this wasn't
      a methadone
      pamphlet it was in general about pain meds
      > Dann
      > ----- Original Message -----
      > From: RG
      > To: DOLOPHINEA_CAFE@yahoogroups.com
      > Sent: 1/4/2004 2:46:16 PM
      > Subject: Re: [METHADONIA ] Re: disket haze
      > I have heard rumors that eating thirty minutes after your dose and
      taking
      > Cimetioine (Tagament) before dosing will increase the blood
      concentration of
      > your medicine. Is any of this correct?
      > Thanks,


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