You can take it in a small dose daily or in a larger dose as needed. Both options require valid medical documentation, but some online services only require a health questionnaire to be filled out and reviewed for approval—meaning no face-to-face video interaction is needed. The interaction is a consequence of blocking hepatic metabolism of vardenafil by ritonavir, a highly potent CYP3A4 inhibitor, which also inhibits CYP2C9. Unapproved therapies, some of which are available in the US and some elsewhere, some of which have data to prove efficacy and some not, include tadalafil Cialis , vardenafil Levitra , yohimbine, phentolamine, trazodone, apomorphine and neutraceuticals. Study 1: This study was designed to evaluate the effect of 5 mg vardenafil compared to placebo when administered to BPH patients on chronic alpha-blocker therapy in two separate cohorts: tamsulosin 0. Cialis Daily tadalafil : This low-dose Cialis works by increasing blood flow to the penis over time, making it easier to have an erection when aroused.The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. Vardenafil is in a class of medications called phosphodiesterase (PDE) inhibitors. It works by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Vardenafil does not cure erectile dysfunction or increase sexual desire. Vardenafil does not prevent pregnancy or the spread of sexually. Vardenafil HCl is a nearly colorless, solid substance with a molecular weight of g/mol and a solubility of mg/mL in water. LEVITRA is formulated as orange, round, film-coated tablets with “BAYER” cross debossed on one side and “”, “5”, “10”, and “20” on the other side corresponding to mg, 5 mg, 10 mg, and.