It may increase your risk of dizziness or fainting. Also tell your doctor if you or any of your family members have or have ever had an eye disease such as retinitis pigmentosa an inherited eye condition that causes loss of vision or if you have ever had sudden severe vision loss, especially if you were told that the vision loss was caused by a blockage of blood flow to the nerves that help you see. Do not stop taking tadalafil without talking to your doctor. Men with BPH usually have difficulty urinating, a decreased flow of urination, hesitation at the beginning of urination, and a need to get up at night to urinate. Tadalafil may cause side effects. Do not change your tadalafil dose or stop taking this medicine without your doctor’s advice. · The typical dose for once-daily Cialis for ED is milligrams (mg) to 5 mg. When used as needed for ED, the usual Cialis dose is 10 mg (with a maximum daily dose of 20 mg). The daily doses are available in and 5-mg tablets. Doctors usually start their patients on the mg dose, though 5 mg may be appropriate if needed for greater efficacy. Side Effects. Headache, stomach upset, back pain, muscle pain, stuffy nose, flushing, or dizziness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. To.