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Viagra and Viagra Side Effects

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Updated November 01, 2009

Classification:

Viagra (sildenafil) belongs to a group of medicines that delay the enzymes called phosphodiesterase from working too quickly. By delaying the action of phosphodiesterase, blood remains in the penis longer, maintaining an erection for a longer period of time.

Form:

  • 25mg tablets
  • 50mg tablets
  • 100mg tablets

Usual Dosage:

  • For adults up to 65 years of age, Viagra 50mg is prescribed to be taken once a day, 30 minutes to 4 hours before intercourse. In situations where 50mg isn't effective, your doctor can prescribe 100mg to be taken once daily 30 minutes to 4 hours before intercourse.

  • For men older than 65 years of age, Viagra 25mg is prescribed to be taken 30 minutes to 4 hours before intercourse. In some circumstances, men older then 65 may have their doses increased.

Instructions:

  • Can be taken with or without food.
  • Take 30 minutes to 4 hours before intercourse.
  • Always start with the lowest effective dose.

Viagra Side Effects to Report to Your Doctor:

Special Warning! - If you experience any sudden change in vision or loss of vision stop taking Viagra and contact your doctor immediately.

Common

  • flushing
  • headache
  • nasal congestion
  • stomach discomfort following meals
Less Common
  • blurred vision, seeing shades of colors differently than before, or sensitivity to light
  • bladder pain
  • cloudy or bloody urine
  • dizziness
  • increased frequency of urination
  • pain on urination
  • diarrhea

If you experience an erection that lasts more than 4 hours seek medical attention.

Drug Interactions and Incompatibility:

  • Protease Inhibitors (Reyataz, Crixivan, Invirase, Norvir, Viracept,Fortovase, Agenerase, Lopinavir) increase the amount of Viagra in your blood and prolongs the action of Viagra. Men on Protease Inhibitors should start with a dose of 25mg with a maximum of 50mg.

  • Nitrates, such as nitroglycerin (e.g., Nitrostat or Transderm-Nitro) - Sildenafil further lowers the blood pressure along with nitrates which may result in an abnormally low blood pressure. Use of Viagra with nitrates should be avoided.

For More information:

For more information on Viagra try About.com's Drug Finder.

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