Diuretics, which are also known as "water pills," are a medication that augments diuresis, or by inducing frequent urination.
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This pharmacological site contains a section on diuretics which delves into the basics, specific sections on loop, thiazide, and K-sparing diuretics as well as diuretic resistance. - Drug Monitor: Diuretics
http://www.thedrugmonitor.com/diuretics.html
Consists of a list of names diuretics go by, a summary of what they do and how as well as conditions they treat and geriatric use issues. - iVillage: Diuretics
http://yourtotalhealth.ivillage.com/diuretics.html
Water pills, properly known as diuretics, are addressed in this article which also discusses examples of thiazide, loop, and potassium-sparing diuretics as well as warnings and possible adverse effects. - Mayo Clinic: Diuretics
http://www.mayoclinic.com/health/diuretics/HI00030