You could get dizzy, faint or have a heart attack or stroke. Because patients with recent heart attacks or stroke, heart pains angina , heart failure, uncontrolled blood pressure or uncontrolled irregular heart beats, severe liver disease, and retinal eye problems were not studied with Cialis, Cialis is not recommended for these patients. Read more on male sexual health on the Sexual Health Australia site. Tell your healthcare provider that you take Cialis. Non—arteritic anterior ischemic optic neuropathy NAION, serious eye condition in one or both eyes, history of—Use with caution. Angina severe chest pain or Arrhythmia irregular heartbeat , uncontrolled or Heart attack within the last 3 months or Heart failure within the last 6 months or Hypertension high blood pressure , uncontrolled or Hypotension low blood pressure or Retinal disorders eye problem or Retinitis pigmentosa an inherited eye disorder or Stroke, recent history of—Should not be used in patients with these conditions. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it.Cialis comes in several different strengths, including: milligrams (mg) 5 mg. 10 mg. 20 mg. The cost for these different strengths depends on whether you have insurance, your individual plan.  · Cialis® also contains tadalafil. If you take too much tadalafil or take it together with these medicines, the chance for side effects will be higher. If you experience a prolonged erection for more than 4 hours or a painful erection for more than 6 hours, contact your doctor immediately. This condition may require prompt medical treatment to. Vision changes. Muscle pain. But there are some differences. With Viagra, there is a higher risk of vision changes than with Cialis. Among people who take Viagra or sildenafil, 3% get blue vision that lasts a few hours. On the other hand, Cialis has a slightly higher risk of muscle pain than Viagra and vardenafil.