There are many precautions and warnings to be aware of when taking Cialis. For example, there are certain other medications that can interact with Cialis. Also, Cialis does not provide any protection against sexually transmitted diseases. Some other Cialis precautions and warnings include the safety of taking Cialis if you have a heart or blood vessel disease, as well as the risk of serious side effects (including heart attack, stroke, and sudden death) in some people taking the drug.

• Heart disease, such as angina, congestive heart failure, or irregular heartbeats
• Kidney disease or kidney failure
• Liver disease or liver failure
• A history of a heart attack, stroke, or life-threatening arrhythmia within the past three months
• Retinitis pigmentosa, which is a rare eye problem
• A history of severe vision loss, including a condition called NAION
• Stomach ulcers
• Other bleeding problems
• Low blood pressure (hypotension)
• High blood pressure (hypertension)
• Sickle cell anemia
• Multiple myeloma
• Leukemia
• A history of priapism, which is a painful erection lasting longer than six hours
• Any condition that causes a penis deformation, such as angulation, Peyronie's disease, or cavernosal fibrosis
• Any allergies.