The purpose of the study is to examine the effect of endoluminally administrated isoproterenol on pelvic pressure increase during flexible ureterorenoscopy in 14 humans. We propose that isoproterenol has potential of reducing intrarenal pressure during ureterorenoscopies. Lower intrarenal pressures may have the advantage of facilitating the procedure and reducing intraoperative complications as bleeding and infections.

Inclusion Criteria:

• Indication for ureterorenoscopy
• Age> 18 years
• Normal blood pressure

Exclusion Criteria:

• Malignant disease in the upper urinary tract
• Heart disease
• Allergy to Isoproterenol
• Use of α-blocking or β-blocking medicine
• Use of Calcium-antagonists
• Use of NSAIDs the last 48 hours
• Present stone or JJ-stent in the ureter
• Neurologic disease in the bladder
• Pregnancy
• Nursing mothers