Answer
Prolonged erections and priapism have been reported with sildenafil; an erection lasting longer than 4 hours requires immediate medical assistance because untreated priapism can cause penile tissue damage and permanent loss of potency.
Sources for this answer
- Revatio 20 mg Film-coated TabletsViatris (formerly Mylan or Upjohn) · emc · SmPC §4.4 Special warnings and precautions for use · Version 47Document updated
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