El-Galley, R <br/><br/>
Long-term efficacy of sildenafil and tachyphylaxis effect.  [electronic resource] 

 -  The Journal of urology  Sep 2001 
 - 927-31 p.  digital 
<br/><br/> Publication Type: Journal Article 
<br/><br/><label>ISSN: </label>0022-5347 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Adult<br/>Aged<br/>Data Collection<br/>Erectile Dysfunction--drug therapy<br/>Humans<br/>Male<br/>Middle Aged<br/>Phosphodiesterase Inhibitors--therapeutic use<br/>Piperazines--therapeutic use<br/>Purines<br/>Sildenafil Citrate<br/>Sulfones<br/>Tachyphylaxis<br/>Time Factors