Viagra Reduces Multiple Sclerosis Symptoms in Animal Model

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Could a drug used to treat erectile dysfunction helped reduce symptoms of multiple sclerosis? Results of a new study showed that Viagra (sildenafil) was able to do just that in animal models.

A possible new use for Viagra

Multiple sclerosis is a chronic, often disabling autoimmune disease in which the body attacks and damages myelin, the fatty substance that protects the nerve fibers in the central nervous system (brain, spinal cord, optic nerves). Damaged myelin forms scar tissue (sclerosis) and causes nerve signals traveling to and from the brain and spinal cord to be interrupted, which produces symptoms, including weakness and numbness in the limbs, loss of balance, blurry vision, and even paralysis.

At the University of Barcelona in Spain, researchers studied the effects of Viagra in an animal model of multiple sclerosis known as experimental autoimmune encephalomyelitis. When the animals had the disease, sildenafil was administered daily. After eight days of treatment, nearly complete recovery was noted in 50 percent of the animals.

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Specifically, the researchers noted that sildenafil helped prevent infiltration of cells that cause inflammation into the white matter of the spinal cord, which in turn reduced damage to the nerve cells and helped promote repair of myelin.

Previous animal studies of Viagra and the other drugs in the class known as phosphodiesterase type 5 inhibitors (i.e., tadalafil [Cialis] and vardenafil [Levitra]) have indicated that they have properties that protect the nervous system and may be useful in treating neurological conditions such as stroke and Alzheimer’s disease.

Currently there is no cure for multiple sclerosis. Treatments include medications that can reduce symptoms,
each the severity of attacks, and possibly slow progression of the disease. Physical therapy and other treatments such as acupuncture, massage, and yoga can help manage symptoms and improve quality of life.

Viagra is well tolerated and has already been used to treat erectile dysfunction in multiple sclerosis patients. These facts, along with the results of this new animal study, have convinced the authors that clinical trials will be conducted to determine the efficacy of Viagra on multiple sclerosis symptoms.

SOURCE:
Pifarre P et al. Acta Neuropathologica 2011; 121:499-508

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