Oral PDE5 drugs approved by the U.S. Food and Drug Administration (FDA) for ED are Avanafil (Stendra), Sildenafil (Viagra), Vardenafil (Levitra), and Tadalafil (Cialis).

Erectile dysfunction or disorder (ED) is the inability to develop and maintain an erection for satisfactory sexual intercourse or activity. Erectile dysfunction or erectile disorders are the preferred terms as opposed to impotence.

Signs and Symptoms

Some self-administered measures may be useful in the primary care setting to screen for and evaluate the degree of ED.

The most commonly used instrument is the International Index of Erectile Function, a 15-item questionnaire that has been validated in many populations and is considered the gold standard to evaluate patients for ED.

The Sexual Health Inventory for Men is a short-form, 5-item questionnaire developed to monitor treatment progress.


If it is determined that ED is a problem, the patient evaluation should include a detailed sexual and medical history and a physical exam. In particular, it is important to evaluate the ED within the context of ejaculatory problems.

A number of specific questions relating to sexual function can help the clinician evaluate the complaint of ED. Additional questions relating to medical history and psychosocial factors also need to be evaluated.

Once a complete sexual and medical history has been completed, appropriate laboratory studies should be conducted. In most cases, a tentative diagnosis can be established with a complete sexual and medical history, physical examination, and limited or no laboratory testing.

Oral Medications Treatment

Although there are numerous options for nonsurgical treatment, oral phosphodiesterase-5 (PDE5) inhibitors should be offered as first-line treatment of patients with ED unless contraindicated. Oral PDE5 drugs approved by the U.S. Food and Drug Administration (FDA) for ED are as follows:

  • Avanafil (Stendra);
  • Sildenafil (Viagra);
  • Vardenafil (Levitra);
  • Tadalafil (Cialis).

These oral medications reversibly inhibit penile-specific PDE5 and enhance the nitric oxide–cGMP pathways of cavernous smooth muscle relaxation; that is, all prevent the breakdown of cGMP by PDE5.
These drugs augment the body’s natural erectile mechanisms, therefore the neural and psycho-emotional stimuli typically needed for arousal still need to be activated for the drugs to be efficacious.


According to a review of all randomized controlled trials evaluating sildenafil by the American Urological Association (AUA) Consensus Panel on Erectile Dysfunction, 36% to 76% of patients receiving the drug were “able to achieve intercourse” during treatment. For tadalafil, four randomized controlled trials revealed that 11% to 47% of patients were “able to achieve intercourse.” Similar efficacy has been observed with vardenafil, although studies are fewer.

Side Effects

Oral ED drugs are generally well tolerated. Typical side effects include headache, flushing, dyspepsia, and nasal congestion.


Patients at high cardiovascular risk should not be treated for ED until their cardiac condition is stabilized. Please contact us if there are any questions still left, and get an absolutely free consultation.