1. Official site from Pfizer that offers information about erectile dysfunction drug Viagra, Includes the details of how Viagra works, its common side effects, and if ,,,
  2. Offers a clinical overview of how prescription drug Viagra affects nitric oxide levels in the blood as well as sections on recommended dosages and warnings,

    www,rxlist,com/viagra-drug,htm -

  3. Provides information about Viagra including its side effects and drug interactions,
  4. Offers information on the oral medications of Viagra, Levitra, and Cialis, the drugs used to treat erectile dysfunction,

    www,mayoclinic,com/health/erectile-dysfunction/MC00029

  5. Sildenafil (Viagra) - Wikipedia

    User-edited article about sildenafil, the drug sold under the name of Viagra, used to treat male erectile dysfunction and pulmonary arterial hypertension,
    en,wikipedia,org/wiki/Viagra
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  6. Saturday Night Live asks the men of New York if they need Viagra,

    www,usrf,org/breakingnews/viagrasnl,html

  7. Brief profile of prescription drug Viagra and its use in the treatment of erectile dysfunction, Covers common questions about getting a prescription, side effects, ,,,

    www,nlm,nih,gov/medlineplus/druginfo/meds/a699015,html

  8. Basic facts on the erectile dysfunction medicine Sildenafil (brand name Viagra), including its potential side effects and interactions with other medications,

    familydoctor,org/online/famdocen/home/men/reproductive/465,html

  9. Provides information about Viagra, Levitra, and Cialis, the medications used to treat erectile dysfunction,

    emedicinehealth,com/nonsurgical_treatment_of_erectile_dysfunction/,