Cialis (tadalafil) is a potent PDE5 inhibitor that stimulates blood flow to the tissues of the penis and helps to treat erectile dysfunction. Just like with other ED medicines you are not supposed to be taking this medication unless you need it. Cialis is not supposed to be taken more often than every 24 hours, although you probably won't need to take it that often anyway. This drug provides every person taking it with up to 36 hours of efficiency. You may also be taking a special form of Cialis regularly - in that case you need to make sure you are taking each dose regularly. Cialis is not supposed to be taken by women, but if you think you absolutely need to take this medicine and are pregnant or breastfeeding, talk to your health care provider in advance. Tell your surgeon that you are currently taking Cialis to make sure your surgery goes as planned, even if it is a minor one. If you have heart disease you may not be allowed to have sex due to health reasons. If you have sex anyway this may put too much strain on your heart and result in serious health effects. Never combine Cialis with nitrate based drugs. Nitrate based drugs are commonly prescribed for the treatment of chest pain. If you are taking any drugs for the chest pain you also have, make sure they are not nitrate drugs. Combining these drugs with Cialis may lead to a sudden drop in blood pressure that can in turn cause more serious health effects. Also tell your health care provider if you have any of the following health conditions that have been reported to have interference with Cialis: heart disease, bleeding disorder, a history a heart attack, congestive heart failure, heart rhythm problems, hypertension, stomach ulcer, a history of stroke, hypotension, retinitis pigmentosa, kidney disease, chest pain, liver disease, or blood cell disorder. Some of these conditions can make it impossible for you to take Cialis, while others will require more careful monitoring by your doctor. Make sure you never exceed the dose of Cialis you have been prescribed, as this is unlikely to make this medication more efficient. Cialis should not be shared with other people, even if you think that will benefit from taking this drug. Other people may have some diseases you are not aware of, and in some cases the presence of these diseases can make taking Cialis inefficient and even dangerous.