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PDE5 Inhibitors

How Medications Like Viagra and Cialis Work

Medications like Viagra, Cialis, Levitra, and Staxyn are known as PDE5 inhibitors. They are a common and effective treatment for erectile dysfunction (ED) and play an important role in penile health, especially after prostate cancer treatment.

This guide explains:

  • How they work: PDE5 inhibitors help increase blood flow to the penis, which is necessary to get and maintain an erection. They also help maintain the health of penile tissue.
  • Two ways to use them:
    • On-demand: Taken before sexual activity, providing erection support for anywhere from 8 to 36 hours, depending on the pill.
    • Daily low-dose: A small daily dose can promote regular erectile responses and help preserve penile tissue after surgery or radiation.
  • Important considerations: It’s crucial to talk to your doctor about side effects, your testosterone levels, and whether these medications are safe for you, especially if you have a heart condition or take blood pressure medication.

Learn More

For more detailed information on how to use these medications effectively, download the full guide.

PDE5 Inhibitors

Monita Sundar, MA

Provincial Program Manager, Prostate Cancer Supportive Care Program

Monita Sundar is the Provincial Program Manager for the Prostate Cancer Supportive Care Program, where she leads a multidisciplinary team dedicated to providing integrated clinical care, patient education, and research-driven support.

With a strong commitment to improving the lives of older adults, Monita is passionate about empowering patients through education and implementing innovative strategies that promote well-being and enhance quality of life.

Her leadership reflects a patient-centered approach that bridges clinical excellence with compassionate care.

Steven Guirguis, MA

Project Manager & Clinical Research Coordinator, Princess Margaret Cancer Centre

Steven is a Project Manager and Clinical Research Coordinator at Princess Margaret Cancer Centre, with academic training in Psychology and Kinesiology.

His work focuses on supporting prostate cancer patients in managing sexual health challenges related to treatment. He brings a strong interest in the mind-body connection to his clinical and research efforts, particularly within survivorship and rehabilitation care.

Outside of work, Steven enjoys spending time with family, staying active, and brings the same passion to the basketball court as he does to his research.

Dr. Ryan Flannigan

Dr. Ryan Flannigan is an Associate Professor, and surgeon-scientist within the Department of Urologic Sciences at the University of British Columbia.

He is the Director of the Urologic Supportive Care Program, Director of the Reproductive & Sexual Medicine Centre within the M.H. Mohseni Institute of Urologic Sciences, and Director of the Male Infertility, Sexual Medicine, and Microsurgery Fellowship Program. His practice is subspecialized in Sexual and Reproductive Medicine, and his research program is focused on developing translational technologies and engineering solutions to advance therapeutics in both sexual medicine and infertility.

He has received national and international awards including the American Urologic Society Rising Star Award, American Society of Andrology Matthew Hardy Young Andrologist Award and has been funded by the Canadian Institute of Health Research, Canadian Foundation for Innovation, Michael Smith Foundation for Health Research, Canadian Urologic Association Scholarship Foundation, American Urology Association, American Society for Reproductive Medicine and the Sexual Medicine Society of North America. 

Dr. Andrew Matthew

Dr. Matthew is a Health and Clinical Psychologist as well as a Clinician-Investigator in the Department of Surgery, Division of Urology, and an Associate Professor in both the Departments of Surgery and Psychiatry at the University of Toronto.

He serves as the Lead Psychologist, Director of the Sexual Health Program, Director of Psychology Training, and Head of the GU Survivorship Program at Princess Margaret Cancer Centre in Toronto, Canada. Dr. Matthew has been instrumental in shaping national and international guidelines for sexual healthcare in cancer (ASCO/CCO, Movember).

His clinical care and research are centered on urologic cancers, focusing on prevention, sexual health, survivorship, and improving patient quality of life.