Furthermore, the longer half-life is the basis for tadalafil’s daily therapeutic use in treating pulmonary arterial hypertension. It works to treat erectile dysfunction by increasing blood flow to the penis during sexual stimulation. National Library of Medicine. If you experience chest pain, dizziness, or nausea during sexual activity, call your doctor immediately or get emergency medical treatment, and avoid sexual activity until your doctor tells you otherwise. CIALIS can cause your blood pressure to drop suddenly to an unsafe level if it is taken with any nitrate medication. Resources and support See the Healthy Male site for more information about erectile dysfunction and its treatment. Cialis should not be used by patients taking nitrates such as nitroglycerin tablets or patches because the combination of these with Cialis could significantly lower blood pressure and lead to fainting or even death in some men.• The recommended starting dose of CIALIS for once daily use is mg, taken at approximately the same time every day, without regard to timing of sexual activity. • The CIALIS dose for once daily use may be increased to 5 mg, based on individual efficacy and tolerability. CIALIS for Once Daily Use for Benign Prostatic Hyperplasia. headache *. upset stomach. runny nose. back pain *. upper respiratory infection. heartburn *. muscle pain. For a list of side effects reported by people taking Cialis in clinical trials, including. The recommended starting dose for Cialis intended for once daily use is mg, take at the same time each day, without regard to timing of sexual activity. This may be increased to 5mg/day based on need and tolerability. May be taken with or without food. Cialis is available as a generic, under the name tadalafil. 3.