Cialis (tadalafil) is a highly-effective medicine that can be purchased online or at your local pharmacy. It belongs to the class of PDE5 inhibitors and works by stimulating blood flow to the tissues of the penis, therefore making it possible for you to get and maintain an erection hard enough to complete sexual intercourse. Take Cialis about an hour before you are planning to have sex. Cialis will help you achieve an erection only when there is enough sexual stimulation. Make sure you get some of that stimulation after taking your dose, as otherwise taking Cialis may not be as effective as you need it to be. Once you have taken this medication, you can count on up to 36 hours of efficiency. This means that you will be able to have sex at any point within this period of time. In most cases Cialis is taken when needed, although there is a variety of this medicine that is intended for every day use. If you have any of the following health conditions you may be started on a lower dose of this medication - to make sure you will benefit from the treatment: a recent history of a heart attack, a history of congestive heart failure, hemophilia, high blood pressure, low blood pressure, retinitis pigmentosa, sickle cell anemia, leukemia, heart disease, multiple myeloma, heart rhythm problems, chest pain, Peyronie's disease, angina, physical deformity of the penis, or a history of a stroke. Some drugs you are taking at the moment can also affect the dose you are being prescribed. Make sure you inform your health care provider of the fact of taking the following drugs: rifampin, alpha blockers, ethosuximide, treatments for erectile dysfunction, clarithromycin, zafirlukast, efavirenz, phenytoin, antifungals, cyclosporine, fluoxetine, troleandomycin, HIV protease inhibitors, medications for high blood pressure, cimetidine, aprepitant, sertraline, or phenobarbital, as well as any other products of the kind, including prescription and over-the-counter drugs and herbal supplements. Cialis is usually well tolerated with only a few mild side effects possible. The following mild side effects can be expected when you start taking Cialis: warmth or redness in your face, sore throat, back pain, upset stomach, diarrhea, stuffy nose, headache, or muscle pain. The following side effects are considered to be serous and need to be reported to your health care provider as soon as possible, as they are likely to get worse over time: lightheadedness, ringing in your ears, vision changes, sweating, swelling in your hands, nausea, irregular heartbeat, chest pain, sudden vision loss, sudden hearing loss, convulsions, priapism, and shortness of breath. Sine side effects of Cialis can be quite individual, you will need to make sure you report any new ones you develop and that are not on the list. If you have any things that are not clear about your treatment - do not hesitate to ask your health care provider for additional information and professional advice.