Healthy men who use drugs to treat impotence may be able to stop worrying - at least for now - about a loss of vision caused by the drugs.
A new study, published in the Archives of Ophthalmology, detected no changes in visual function, signs of retina damage or intraocular pressure after the daily use for six months of sildenafil (Viagra) or tadalafil (Cialis).
Viagra and Cialis are commonly used to treat erectile dysfunction and are also being considered for use in other disorders. However, these drugs have been associated with visual side effects, such as blue-tinged or blurred vision and light sensitivity, explain Dr William H. Cordell, at Eli Lilly and Company in Indianapolis, and colleagues.
To investigate further, Cordell's team conducted a study of healthy men with or without mild erectile dysfunction, between 30 and 65 years old and with no ophthalmologic abnormalities or risk factors.
The men were randomly assigned to daily treatment with Viagra 50 mg, Cialis 5mg, or placebo. The analysis included 155 men who completed six months of treatment, and 212 men who completed three months.
What the study found
Following treatment with the two erectile dysfunction drugs, no clinically important side effects or differences were detected among the three groups at three months, six months, or at a post treatment follow-up four to six weeks later.
Similarly, treatment had no effect on visual acuity, colour discrimination, intraocular pressure or any other functions.
No cases of non-arteritic anterior ischaemic optic neuropathy or other serious ocular damage occurred during the trial, the authors note. Non-arteritic anterior ischaemic optic neuropathy is characterized by sudden visual loss, swelling of the optic disc and sometimes haemorrhaging in the area. The condition is usually permanent, and up to 20% of patients can suffer total visual loss.
The authors conclude that the findings indicate no cumulative damage or effect of clinical significance for 5mg of Cialis or 50mg or Viagra taken daily for six months.
However, they caution that their findings can't be generalised to patients who have coexisting systemic or ocular disease. – (Reuters Health, April 2009)
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