Joseph Zadra, BSc, MD, CM, FRCSC

The Male/Female Health and Research Centre
Royal Court Medical Centre

1 Quarry Ridge Road, Suite 206

Barrie, Ontario, Canada
L4M 7G1

Speciality: Urology

 Research Interests: Benign Prostatic Hyperplasia / Bladder Outlet Obstruction, Bladder Cancer, Erectile Dysfunction, Female Sexual Dysfunction, Interstitial Cystitis/Bladder Pain Syndrome, Nocturia, Overactive Bladder, Prostate Cancer


Dr. Joseph A. Zadra has been practicing Urology in Barrie, Ontario for over 20 years. He has been conducting clinical trials since 1996, and has been the Principal Investigator for over 127 clinical trials in urology. Dr. Zadra has conducted clinical trials for many urologic conditions and diseases, including benign prostatic hyperplasia, overactive bladder, interstitial cystitis, prostate cancer, nocturia, and female sexual dysfunction.

Dr. Zadra is fluent in English, French, Italian, and Spanish. His current positions include Assistant Clinical Professor in the Department of Surgery (Urology) at McMaster University. Dr. Zadra is also on the staff of both the Huronia District Hospital in Midland, Ontario and the Royal Victoria Hospital in Barrie, Ontario.

Dr. Zadra has been a speaker on numerous Advisory Boards, including Abbott, AstraZeneca, Bayer, Ferring, and Pfizer. He is the Chairman of the Department of Urology for the Royal Victoria Hospital, as well as the Secretary of the Department of Surgery. He is a member of the American, Ontario, and Canadian Urological Associations, as well as the Ontario and Canadian Medical Association.


Click to view Dr. Joseph Zadra's Publications

Andriole GL, Bostwick DG, Brawly OW, Gomella LG, Marberger M, Montorsi F, Pettaway CA, Tammela TL, Teloken C, Tindall DJ, Somerville MC, Wilson TH, Fowler IL, Rittmaster RS; REDUCE Study Group. Effect of dutasteride on the risk of prostate cancer. N Engl J Med 2010 Apr 1; 362(13): 1192-202. PMID: 20357281 / doi: 10.1056/NEJMoa0908127

Smith MR, Egerdie B, Hernández Toriz N, Feldman R, Tammela TL, Saad F, Heracek J, Szwedowski M, Ke C, Kupic A, Leder BZ, Goessl C; Denosumab HALT Prostate Cancer Study Group. Denosumab in men receiving androgen-deprivation therapy for prostate cancer. N Engl J Med 2009 Aug 20; 361(8): 745-55. Epub 2009 Aug 11. PMID: 19671656 / doi: 10.1056/NEJMoa0809003

Gittelman M, Pommerville PJ, Persson BE, Jensen JK, Olesen TK; Degarelix Study Group. A 1-year, open label, randomized phase II dose finding study of degarelix for the treatment of prostate cancer in North America. J Urol 2008 Nov; 180(5):1986-92. Epub 2008 Sep 17. PMID: 18801505 / doi: 10.1016/j.juro.2008.07.033

Nickel JC, Downey J, Clark J, Casey RW, Pommerville PJ, Barkin J, Steinhoff G, Brock G, Patrick AB, Flax S, Goldfarb B, Palmer BW, Zadra J.  Levofloxacin for chronic prostatitis/chronic pelvic pain syndrome in men: a randomized placebo-controlled multicenter trial.  Urology 2003 Oct; 62(4):614-617.  PMID: 14550427

Seger M, Zadra JA, Yale JF.  Cardiovascular safety of Levitra™ (Vardenafil) in patients receiving antihypertensive medications: analysis of phase III clinical trials.  2003 Oct.

Sarosdy MF, Schellhammer P, Bokinsky G, Kahn P, Chao R, Yore L, Zadra J, Burzon D, Osher G, Bridge JA, Anderson S, Johansson SL, Lieber M, Soloway M, Flom K.  Clinical evaluation of a multi-target fluorescent in-situ hybridization assay for detection of bladder cancer.  J Urol 2002 Nov; 168(5):1950-1954.  PMID: 12394683

Diokno AC, Chancellor MB, Zadra JA, et al.  Tolterodine (Detrol®) improves incontinence and nocturia in urologist based study.  J Urol 1999; 161:987.

Gleave M, Goldenberg SL, Zadra JA, et al.  Randomized comparative study of 3 VS8 months of neoadjuvant hormonal therapy prior to radical prostatectomy: biochemical and pathological effects.  J Urol 1999; 161:592.

Casey R, Zadra J, Khonsari H.  A comparison of etodolac (Ultradol) with acetaminophen plus codeine (Tylenol #3) in controlling post-surgical pain in vasectomy patients.  Curr Med Res Opin 1997; 13(10):555-563.  Erratum in: Curr Med Res Opin 1997; 14(1):63.  PMID: 9327190

Bruce AW, Zadra JA, Robinette MA, Toi A, Bulbul MA, Llalno M.  The roles of prostatic specific antigen and transrectal ultrasound in staging localized prostatic cancer.  J Urol 1989; 141:277 A.

Fleshner N, Zadra JA, Bruce AW.  Comparison of two assays of prostatic specific antigen with clinical correlation.  J Urol 1989; 141:183 A.

Trachtenberg J, Zadra J.  Steroid synthesis inhibition by ketoconazole: sites of action.  Clin Invest Med 1988 Feb; 11(1):1-5.  PMID: 2966691

Zadra JA, Jewett MA, Keresteci AG, Rankin JT, St Louis E, Grey RR, Pereira JJ.  Nonoperative urinary diversion for malignant ureteral obstruction.  Cancer 1987 Sep 15; 60(6):1353-1357.  PMID: 3621117

Zadra JA, Struthers NW, Franco N.  Further reflections on two stage urethroplasties.  J Urol 1987; 137:167 A.

Zadra JA, Trachtenberg J.  Total androgen ablation therapy in the treatment of advanced prostatic cancer.  J Urol 1986; 135:201 A.

Zadra JA, Jewett MAS, Keresteci AG, Rankin JT.  Contemporary management of malignant ureteral obstruction – analysis of 135 cases.  J Urol 1985; 133:236 A.

Zadra JA, Trachtenberg J.  Sites and degree of inhibition of ketoconazole on testosterone and cortisol production.  J Urol 1984; 131:122 A.

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