Combined use could lead to additional lowering of blood pressure, possibly to unsafe levels. Tell your doctor if any of these symptoms are severe or do not go away: headache. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Take tadalafil exactly as directed. One of the first Cialis ads aired at the Super Bowl. Tell your doctor if tadalafil is not working well or if you are experiencing side effects.The drug comes in low-dose versions that can be taken daily. This means you can have sex at any time, rather than needing to take a pill from time to time as needed like other ED brands. The starting dose for daily-use Cialis is milligrams (mg). If that doesn’t work, you can increase your daily dose up to 5 mg. Can you legally buy Cialis online? Yes, it is legal to purchase Cialis online. However, people should only use reputable telehealth companies and online pharmacies. headache. indigestion. back pain. muscle pain. flushing. stuffy nose. Patients who get back pain and muscle aches usually get them 12 to 24 hours after taking Cialis and these usually go away by.