VIAGRA RETINAL ( and other ) SIDE EFFECTS :this is everything ( or, almost everything ) published so far on it; it's a good starting point. As all side effects in medicine, time will tell:
=========================================================
[ 1 ]
Message 4327441
SAN FRANCISCO, May 4, 1998 /PRNewswire/ -- Today, doctors at the American Academy of Ophthalmology, the world's largest organization of eye physicians and surgeons, warned users of the newly-approved anti-impotence drug, Viagra, about the potential side effects that may affect vision.
Michael F. Marmor, MD, Professor of Ophthalmology at Stanford University and spokesperson for the Academy, said that a moderate percentage of people taking Viagra have experienced problems with their vision. "FDA clinical trials show that taking the medication, especially at higher doses, can cause some retinal dysfunction and affect the way we see for a number of hours." Patients reported visual disturbances described as bluish color tinge and light sensitivity. Dr. Marmor said a clinical study showed that electrical measures of retinal function dropped by 30 to 50 percent and lasted for at least five hours after taking a high dose of Viagra.
"On the surface, seeing the world with a bluish tinge may just be annoying," Dr. Marmor said. It is not known, however, whether or not the drug causes any permanent changes in vision. "We need to do some studies about the long-term effects of taking Viagra." In the meantime, Dr. Marmor urged those with retinal eye conditions such as macular degeneration or retinitis pigmentosa to use the drug with caution. "Stay at the lowest dose level possible," he said. According to the FDA, the recommended dose level for most patients is 50 mg.
The American Academy of Ophthalmology is the world's largest organization of eye physicians and surgeons (Eye M.D.s), with more than 23,000 members. The mission of the Academy is to achieve accessible, appropriate and affordable eye care for the public by serving the educational and professional needs of ophthalmologists. Visit the Academy's website at www.eyenet.org.
SOURCE American Academy of Ophthalmology
CO: American Academy of Ophthalmology
ST: California
==========================================================
[ 2 ]
quote.bloomberg.com
Scientists Using Gene-Altered Mice to Study Diseases, Post Says
Scientists Using Gene-Altered Mice to Study Diseases, Post Says
Washington, June 7, 1998 (Bloomberg) -- Scientists at the National Institutes of Health in the U.S. are using mice genetically engineered with human diseases to better understand disease processes and find cures faster, The Washington Post reported in its final Sunday edition. Scientists can then analyze as many times as needed the mice, which are injected at embryonic stages with the same biological defects that cause diabetes, cancer or cystic fibrosis in humans, the paper said, citing NIH immunologist Ronald Schwartz. Critics, however, say the practice is cruel and contradicts recent, more compassionate trends in high-technology animal research, the newspaper said.
Trial tests for Pfizer Inc.'s impotence-fighting Viagra found that some pregnant mice treated with the drug produced blind offspring. (WP, 6/7, A1, www.washingtonpost.com)
=========================================================
[ 3 ]
case-against.com
Technology and Culture Commentary
The Case Against
Dealing with the Devil
Viagra can be a Killer
by Jim Nourse and Jennifer Montgomery May 22, 1998
Web posted at: 6::30 p.m. EST
Reported minor side effects included slight vision impairment caused by decreases in electrical measurements of retinal function. Such decreases lasted for at least five hours and occurred only after test subjects had taken prescribed high dosages. Naturally, long-term studies have not yet been compiled on the side effects of the pill. As a result the medical world cannot report with certainty whether or not such slight impairments could evolve into permanent changes in vision or whether they will simply remain annoying, yet manageable, side effects.
========================================================
[ 4 ]
Message 4799228
June 10, 1998
Deaths of Men Taking Viagra
Point to Limits of Drug Testing
By NANCY ANN JEFFREY and ROBERT LANGRETH
Staff Reporters of THE WALL STREET JOURNAL
Debora Farber, associate director of the Jules Stein Eye Institute at the University of California at Los Angeles, is currently testing Viagra on animals to see if it can harm their eyesight. "We are very, very concerned that something could happen in patients taking Viagra for long periods of time," she says. Pfizer says it has done extensive studies on Viagra's potential for eye-related side effects in humans and has found nothing, other than the occasional and temporary blue-green tinge to vision.
[NOTE: The above DrFarber is the same DrFarber that published this article on retinal degeneration when PDE is desrtoyed:
===========================================================
[ 5 ]
Message 3203236
SCIENCE - VOL. 272 - 17 MAY 1996
Retinal Degeneration in Mice Lacking the,gamma
Subunit of the Rod CGMP Phosphodiesterase
By Stephen H. Tsang, Peter Gouras, Clyde K. Yamashita,
Hild Kjeldbye, John Fisher,* Debora B. Farber, Stephen P. Goff-,
The retinal cyclic guanosine 3',5'-monophosphate (CGMP) phosphodiesterase (PDE) is a key regulator of phototransduction in the vertebrate visual system. PDE consists of a catalytic core of a and b subunits associated with two inhibitory g ( gamma ) subunits. A gene-targeting approach was used to disrupt the mouse PDE-g gene. This mutation resulted in a rapid retinal degeneration resembling human retinitis pigmentosa. In homozygous mutant mice, reduced rather than increased PDE activity was apparent; the PDEap dimer was formed but lacked hydrolytic activity. Thus, the inhibitory -g subunit appears to be necessary for integrity of the photoreceptors and expression of PDE activity in vivo
Our results indicate that an interaction between the gamma subunit and PDE ab is essential for the proper activation of PDE and that all three subunits may be essential for assembly of a stable, active holo enzyme. The genetic loss of PDEGamma is manifested as an increase in cGMP content in the developing mutant retinas.
The hi cGMP concentrations may keep cGMP-gated cationic channels open
continuously and lead to an excessive energy load on the rod
photoreceptors resulting in degeneration.
..........................................
The above Authors are currently at :
C.K. Yamash la and C. S. Farber, Jules Stein Eye Institute. Molecular Biology Institute and Department of Ophthalmology UCLA School of Medicine, Los Angeles, CA 90095, USA.
S.H. Tsang, J Fisher, S. P. Goff, Howard Hughes Med co nstitute, Department of Biochemistry and Molecular Biophysics, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA.
P Gouras and H. Kjeldtye, Edward Harkness Eye Institute, Department of Ophthalmology, Columbia University, College of Physicians and Surgeons, New York, NY 10O32, USA.
'Present address: Regeneron Pharmaceutcas, Tarry lesson, NY 10591. USA,
========================================================
[ 6 ]
And finally Barons article of July 6 1998
interactive.wsj.com.
By Andrew Barry, Barons, July 6, 1998, page MW5
IS VIAGRA STARTING TO FADE?
So far, Pfizer has done a good job addressing safety concerns about the drug, including the deaths of men taking Viagra. But there hasn't been any long-term testing of Viagra. One concern is whether the drug begins to lose its effectiveness over time. Pfizer says there's no evidence of this.
However, Flynn points out that Viagra users are increasingly favoring higher-dose pills. "This suggests people aren't getting the desired effect from the lower dosage," he reasons. Viagra is available in dosages of 25, 50 and 100 milligrams. The 100-milligram pills have risen to 22% of prescriptions from 8% initially. One problem with the stronger pills is that they cause a higher incidence of visual color disturbances, or bluish vision, according to Neil Sweig, an analyst at Southeast Research Partners.
Pfizer downplays the blue-vision side effect, which occurs in about 10% of men taking the 100-milligram pills, saying it's "confident" there are no long-term effects on the vision of those taking the proper dosage. But Sweig, citing the views of many eye doctors, wrote recently that the blue-vision issue could be "serious." He said blue vision appears to be a "unique" side effect of Viagra that isn't present with any disease or other drug and that "some event" is occurring in the retina to trigger the problem. It's too early, he wrote, to determine whether Viagra has no long-term adverse effect on the eyes.
===============================================================
TA
PS For previously published other Viagra side effect reports please go to the following posts:
Good Morning Vietnam, ( the radio station where it all started:
Message 4716042
Report No 1: Message 4716059
Report No 2: Message 4716080
Report No 3: there is none .
Report No 4: techstocks.com
Report No 5: fresnobee.com
Message 4739522
Report No 6 : Message 5064065
|
