Tadalafil is its active ingredient and is available as a generic drug. Knowledge is Power It’s imperative to consult a healthcare professional before starting any medication, including Cialis. In trials of the drug, individuals taking Cialis saw a significant reduction in the frequency and urgency of urination and improved urine flow. You should take tadalafil one time a day. Mechanism of action[ edit ] Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and the smooth muscle of the corpus cavernosum. Interestingly, Cialis has been more linked to improved self-esteem and other psychological factors than the other PDE5 medications.DRUG_DESCRPTION Compare DRUG_NAME prices and find coupons that could save you up to 80% instantly at pharmacies near you such as CVS, Walgreens, Walmart, and . Best prices for generic cialis on the Internet! The safest way is to ask your physician to try an alternate prescription. Detailed dosage guidelines and administration information for Cialis (tadalafil). Includes dose adjustments, warnings and . Cialis lasts up to 36 hours in the body, while Viagra lasts 4–6 hours in the body. Both are taken 30 minutes before sex. Cialis can cause limb pain, while Viagra can cause vision change, rash.