Phosphodiesterase type 5 PDE5 inhibitors. In , Pfizer scientists discovered that sildenafil, which also inhibits the PDE5 enzyme, caused penile erection in males participating in a clinical study of a heart medicine. One of these is PAH. However, if you’d feel more comfortable talking with a healthcare provider virtually rather than in person, you can consider requesting an online ED prescription instead. Prolonged erections can be dangerous. Counterfeit medicines can be very dangerous. Cialis has a longer duration of action, up to 36 hours, compared to other ED medications.AdComplete the Online Consultation with our Doctor. Personalize Your Needs. If Appropriate, Get a Prescription for ED from RexMD®. Free Shipping has been visited by 10K+ users in the past monthFree Shipping · Discreet Packaging · Real Doctors · Personalized PlanServices: Telemedicine, Privacy Policy, Telehealth and more. AdGet a Prescription for ED treatment, discreetly deliverED to your ive Offers · How It Works · Get More InfoTypes: Get Started · Tadalafil · Sildenafil. A generic version of Cialis is available. See tadalafil prices (from $ for 30 tablets Cialis prices mg Cialis oral tablet from $ for 30 tablets 5 mg Cialis oral tablet from $ for 30 tablets 10 mg Cialis oral tablet from $2, for 30 tablets Cialis oral tablet from $2, for 30 tablets.