Posted by Quintal on April 1, 2007, at 18:59:55
In reply to Re: Pergolide recalled » Quintal, posted by linkadge on April 1, 2007, at 18:49:14
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ANIMAL TOXICOLOGYRetinal Pathology in Albino Rats
Pathologic changes (degeneration and loss of photoreceptor cells) were observed in the retina of albino rats in the 2-year carcinogenicity study with pramipexole. These findings were first observed during week 76 and were dose dependent in animals receiving 2 or 8 mg/kg/day (plasma AUCs equal to 2.5 and 12.5 times the AUC in humans that received 1.5 mg tid). Similar findings were not present in rats receiving 0. 3 mg/kg/day (plasma AUC equal to 0.3 times the AUC in humans that received 1.5 mg tid).
Investigative studies demonstrated that pramipexole reduced the rate of disk shedding from the photoreceptor rod cells of the retina in albino rats, which was associated with enhanced sensitivity to the damaging effects of light. In a comparative study, degeneration and loss of photoreceptor cells occurred in albino rats after 13 weeks of treatment with 25 mg/kg/day of pramipexole (54 times the highest clinical dose on a mg/m2 basis) and constant light (100 lux) but not in pigmented rats exposed to the same dose and higher light intensities (500 lux). Thus, the retina of albino rats is considered to be uniquely sensitive to the damaging effects of pramipexole and light. Similar changes in the retina did not occur in a 2-year carcinogenicity study in albino mice treated with 0.3, 2, or 10 mg/kg/day (0. 3, 2. 2 and 11 times the highest clinical dose on a mg/m2 basis). Evaluation of the retinas of monkeys given 0.1, 0.5, or 2. 0 mg/kg/day of pramipexole (0. 4, 2. 2, and 8. 6 times the highest clinical dose on a mg/m2 basis) for 12 months and minipigs given 0.3, 1, or 5 mg/kg/day of pramipexole for 13 weeks also detected no changes.
The potential significance of this effect in humans has not been established, but cannot be disregarded because disruption of a mechanism that is universally present in vertebrates (ie, disk shedding) may be involved.
http://www.rxlist.com/cgi/generic/prampex_cp.htm
__________________________________________________It's a shame because it seems to be a pretty good mood stabilizer and anxiolytic (at least at the doses I've been taking). But I don't want to damage my eyesight.
Q
poster:Quintal
thread:746010
URL: http://www.dr-bob.org/babble/20070327/msgs/746086.html