Claritin/loratadine 
Author Message
 Claritin/loratadine

Summary: My allergist prescribed Claritin, and the drug information sheet
         scares me.  Can someone put some perspective on the information
         I read there?

I posted this to sci.med recently, and got zero replies.  I'm hoping someone
here can help.  When I recently commented to my allergist that Seldane
isn't very effective for me, he gave me some samples of Claritin, to see
if it works better for me.

Now, I'm not a chicken-little or a Luddite when it comes to things that
modern medical science invents to make my life better, but I do try to
stay informed about what I'm putting into my body.  The samples included
the standard, very long drug information sheet, which I read.  One part
of it concerned me, but I'm not medically literate enough to interpret
it properly, so I'm putting it out here to ask for feedback.  (Note -
recommended dose is 10 mg/day for {*filter*}s.  I weigh approximately 70 kg).

"Carcinogenesis, Mutagenesis, and Impairment of Fertility:  In an 18-month
oncogenicity study in mice and a 2-year study in rats, loratadine was
administered in the diet at doses up to 40 mg/kg (mice) and 25 mg/kg (rats).
In the carcinogenicity studies, pharmacokinetic assessments were carried
out to determin animal exposure to the drug.  AUC data demonstrated that
the exposure of mice given 40 mg/kg of loratadine was 3.6 (loratadine)
and 18 (active metabolite) times higher than a human given 10 mg/day.  
Exposure of rats given 25 mg/kg of loratadine was 28 (loratadine) and
67 (active metabolite) times higher than a human given 10 mg/day.  Male
mice given 40 mg/kg had a significantly higher incidence of hepatocellular
tumors (combined adenomas and carcinomas) than concurrent controls.
In rats, a significantly higher incidence of hepatocellular tumors
(combined adenomas and carcinomas) was observed in males given 10 mg/kg
and males and females given 25 mg/kg.  The clinical significance of
these findings during long-term use of CLARITAN Tablets is not known."

It goes on to talk about mutagenicity and decreased fertility in male rats
given 64 mg/kg.  Also, "produced hepatic microsomal enzyme induction in
the mouse at 40 mg/kg and rat at 25 mg/kg, but not at lower doses."

Now, I know that these tests were done at much greater doses than in
humans, and I also take some comfort in the fact that this drug was
approved by the FDA (should I?).  But it seems to me that this data
indicates that there are some real potential problems with this drug's
effect on the liver.  It may be relevant that the elimination half-life
of this drug is 8.4 hours (loratadine) and 28 hours (metabolites), and
that these numbers go up significantly for people with liver damage.
In other words, the body eliminates it slowly, and it seems like the liver
is the main organ that does so.

My allergies are fairly severe, but not bad enough that I want to risk
liver cancer.  Am I being alarmist?  Thanks for any perspective that you
can shed on this.

--
--------------------------------------------------------------
Bob Herlien
MBARI (Monterey Bay Aquarium Research Institute)



Thu, 03 Oct 1996 06:01:29 GMT
 Claritin/loratadine
: Summary: My allergist prescribed Claritin, and the drug information sheet
:          scares me.  Can someone put some perspective on the information
:          I read there?

: I posted this to sci.med recently, and got zero replies.  I'm hoping someone
: here can help.  When I recently commented to my allergist that Seldane
: isn't very effective for me, he gave me some samples of Claritin, to see
: if it works better for me.

: Now, I'm not a chicken-little or a Luddite when it comes to things that
: modern medical science invents to make my life better, but I do try to
: stay informed about what I'm putting into my body.  The samples included
: the standard, very long drug information sheet, which I read.  One part
: of it concerned me, but I'm not medically literate enough to interpret
: it properly, so I'm putting it out here to ask for feedback.  (Note -
: recommended dose is 10 mg/day for {*filter*}s.  I weigh approximately 70 kg).

: "Carcinogenesis, Mutagenesis, and Impairment of Fertility:  In an 18-month
: oncogenicity study in mice and a 2-year study in rats, loratadine was
: administered in the diet at doses up to 40 mg/kg (mice) and 25 mg/kg (rats).
: In the carcinogenicity studies, pharmacokinetic assessments were carried
: out to determin animal exposure to the drug.  AUC data demonstrated that
: the exposure of mice given 40 mg/kg of loratadine was 3.6 (loratadine)
: and 18 (active metabolite) times higher than a human given 10 mg/day.  
: Exposure of rats given 25 mg/kg of loratadine was 28 (loratadine) and
: 67 (active metabolite) times higher than a human given 10 mg/day.  Male
: mice given 40 mg/kg had a significantly higher incidence of hepatocellular
: tumors (combined adenomas and carcinomas) than concurrent controls.
: In rats, a significantly higher incidence of hepatocellular tumors
: (combined adenomas and carcinomas) was observed in males given 10 mg/kg
: and males and females given 25 mg/kg.  The clinical significance of
: these findings during long-term use of CLARITAN Tablets is not known."

: It goes on to talk about mutagenicity and decreased fertility in male rats
: given 64 mg/kg.  Also, "produced hepatic microsomal enzyme induction in
: the mouse at 40 mg/kg and rat at 25 mg/kg, but not at lower doses."

: Now, I know that these tests were done at much greater doses than in
: humans, and I also take some comfort in the fact that this drug was
: approved by the FDA (should I?).  But it seems to me that this data
: indicates that there are some real potential problems with this drug's
: effect on the liver.  It may be relevant that the elimination half-life
: of this drug is 8.4 hours (loratadine) and 28 hours (metabolites), and
: that these numbers go up significantly for people with liver damage.
: In other words, the body eliminates it slowly, and it seems like the liver
: is the main organ that does so.

: My allergies are fairly severe, but not bad enough that I want to risk
: liver cancer.  Am I being alarmist?  Thanks for any perspective that you
: can shed on this.

: --
: --------------------------------------------------------------
: Bob Herlien
: MBARI (Monterey Bay Aquarium Research Institute)

--
      _/   _/    _/   _/_/_/      _/    _/      _/        _/_/_/     _/_/_/  
Bob,

  You are not being an alarmist , but I don't think you have to worry about
liver cancer. What the drug co's do it basically od the rat to see where the
problems begin and then compare that to the human dose. Youl'l never hit 40mg
per day  because the {*filter*} dose is 10mg daily and that lasts for 24 hrs.
   Here's what you have to worry about though. Don't take the pill with any
Erythomycin products or an anti-fungal called nizoril(ketoconizole) because
it will cause something called tachacardia with is rapid heartbeat and
that could cause a heartattack.
   Your best bet is to talk to your pharmacist beacause he can get into more.
     _/  _/     _/   _/    _/    _/   _/     _/  _/      _/    _/   _/    _/
    _/ _/      _/   _/          _/  _/      _/    _/      _/         _/
   _/_/       _/   _/          _/ _/       _/      _/       _/         _/
  _/  _/     _/    _/     _   _/   _/     _/ _/_/_/ _/        _/        _/
 _/    _/   _/     _/    /_/ _/     _/   _/          _/   _/    _/  _/    _/
_/      _/ _/       _/_/_/  _/       _/ _/            _/   _/_/_/    _/_/_/

Mr. Carmine Zingariello
Computer Science Undergrad
Northeastern University




Fri, 04 Oct 1996 12:12:48 GMT
 Claritin/loratadine

:   You are not being an alarmist , but I don't think you have to worry about
: liver cancer. What the drug co's do it basically od the rat to see where the
: problems begin and then compare that to the human dose. Youl'l never hit 40mg
: per day  because the {*filter*} dose is 10mg daily and that lasts for 24 hrs.
:    Here's what you have to worry about though. Don't take the pill with any
: Erythomycin products or an anti-fungal called nizoril(ketoconizole) because
: it will cause something called tachacardia with is rapid heartbeat and
: that could cause a heartattack.
:    Your best bet is to talk to your pharmacist beacause he can get into more.

I believe that you are mistaken in your statement that Claritin can cause
an irregular heartbeat when taken with erythromycin products, Niz{*filter*}or
Sporanox.  The problem lies in taking the prescription
antihistamines Seldane or Hism{*filter*}with any of these items.  However, it
is possible that your information is more current than mine, and if so
please let me know.
--
---------------------------------------------------------------------------

---------------------------------------------------------------------------



Sun, 06 Oct 1996 09:14:29 GMT
 Claritin/loratadine


Quote:
>I believe that you are mistaken in your statement that Claritin can cause
>an irregular heartbeat when taken with erythromycin products, Niz{*filter*}or
>Sporanox.  The problem lies in taking the prescription
>antihistamines Seldane or Hism{*filter*}with any of these items.  However, it
>is possible that your information is more current than mine, and if so
>please let me know.

I think it's more a matter of exercising proper prudence in avoiding the
combinations given the experience with the other two antihistamines
than a matter of having observed this drug interaction with loratadine.
I think the most recent FDA labelling includes the observation that
using loratadine with these {*filter*} does in fact elevate {*filter*} levels
of loratadine and its primary metabolite, but that no arrhythmias
were observed in the (arguably small) experimental group.  That doesn't
mean that the combination is safe.

--
Steve Dyer



Sun, 06 Oct 1996 13:55:46 GMT
 Claritin/loratadine

Almost all {*filter*} are metabolised in the liver and loratadine is no exception.
The drug has been used in Europe for a number of years with very few reported
major side effects.  The mutagenecity and carcinogenicity in rats and mice are
at doses way higher than humans are taling.  When you consider that 10mg /70kg
translates to 0.14 mg/kg.  Also, consider that the metabolites are eventually
excreted and not usually remetabolized by the liver.



Fri, 18 Oct 1996 12:59:07 GMT
 
 [ 5 post ] 

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