A to Z of MS
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A to Z of MS Sildenafil citrate (Viagra)
Product name
Viagra
Sildenafil citrate is an effective, well tolerated treatment for men with erectile dysfunction. The NICE Guideline suggests that men with MS with persisting erectile dysfunction should be offered 25-100mg sildenafil citrate unless there is a medical reason not to do so.
How sildenafil citrate works
Erectile dysfuntion is the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. In multiple sclerosis this is commonly associated with bladder problems and both disorders are believed to be as a direct result of damage to the nerves in the spinal cord.
Sildenafil works by delaying the action of enzymes called PDE5 (phosphodiesterase type 5), which regulate blood flow in the penis. Altering levels of this enzyme means that normal sexual stimulation leads to better erections.
How is sildenafil given
Sildenafil is taken orally one hour before sexual activity is planned; maximum dose frequency is once a day.
Side effects and contraindications
Common side effects include headaches, flushing, upset stomach, visual disorders, nasal congestion and dizziness. Sildenafil should not be taken by people receiving treatment with drugs containing nitrates, such as are used to treat angina. Sildenafil must be used with caution by people with existing heart conditions or problems with liver or kidney function or low blood pressure.
Studies have shown that sildenafil is not effective in treating women with sexual dysfunction in MS.
References
Fowler CJ, et al.
A double blind, randomised study of sildenafil citrate for erectile dysfunction in men with multiple sclerosis.
Journal of Neurology, Neurosurgery & Psychiatry 2005;76(5):700-705.
abstract
Dasgupta R, et al.
Efficacy of sildenafil in the treatment of female sexual dysfunction due to multiple sclerosis.
Journal of Urology 2004 ;171(3):1189-1193.
abstract
Patient Information Leaflet
- Viagra (EMC website)