Like all medications, Avaforce 50 may cause side effects in some people. Common side effects may include headache, flushing, indigestion, stuffy or runny nose, dizziness, and back pain. Serious side effects are rare but may include sudden vision loss or changes, sudden hearing loss or ringing in the ears, chest pain, and priapism (a prolonged erection lasting more than four hours). If you experience any severe or persistent side effects while taking Avaforce 50, seek medical attention promptly.