Cialis (tadalafil) is a very efficient PDE5 inhibitor that you may use in case you experience problems with getting and maintaining an erection. It can be recommended for patients who have repeated or temporary inability to get erections. Cialis tablets are yellow and almond shaped and come in the doses of 5 mg, 10 mg and 20 mg. You can take Cialis with some food or without, but make sure you follow all the recommendations your health care provider gave. Cialis can help you to achieve an erection. Drinking alcohol may worsen some of the side effects Cialis has been reported to cause, especially lightheadedness and dizziness. If you have ever experienced an allergic reaction to tadalafil or similar drugs make sure you talk to your doctor in advance. If you have a serious side effect that can be described as a prolonged erection that can also be painful (priapism), report it to your health care provider as soon as possible or seek emergency medical assistance at your local emergency center. Sudden vision loss is a rare serious side effect caused by the decreased blood flow to the optic nerve of the eye, although in many cases people who get this condition are older than 50 years, smoke, have high blood pressure, diabetes, heart disease, high cholesterol or pre-existing eye problems. If you get nauseated, dizzy or experience numbness, tingling or pain while having sex these may be the serious side effects of taking Cialis. In that case stop taking this medicine and talk to your doctor as soon as possible to see if you will be able to carry on with the treatment. The following mild side effects do not have to be reported immediately, as they are most likely to go away on their own: indigestion, cough, diarrhea, stomach pain, backache, muscle pain, heartburn, flushing, and headache. If the side effects mentioned persist and do not stop even when the effects of Cialis are gone, talk to your doctor, as you may need your dose to be adjusted (probably lowered). It's also very important that you tell the doctor if you are taking any of the following medications that have been reported to interfere with the effects of Cialis: antidepressants, antibiotics, rifampin, isoniazid, HIV/AIDS medicine, imatinib, doxazosin, antifungals, heart or blood pressure medications, seizure medications, diclofenac, and conivaptan. The drugs mentioned can affect the dose you are originally prescribed - all that to avoid dangerous drug interference.