So, even if the nerves or blood vessels going to your penis are not working so well, a tablet can cause the blood flow to increase in your penis, and cause an erection. Tablets can treat ED caused by various underlying conditions. Note: none of these tablets will cause an erection unless you are sexually aroused. The following are common laboratory tests to evaluate erectile dysfunction: Urinalysis: An abnormal urinalysis may be a sign of diabetes mellitus and kidney damage. Lipid profile: High levels of LDL cholesterol (bad cholesterol) in the blood promotes atherosclerosis. This section needs additional citations for verification. (May 2010) best price cialis buy cialis online generic cialis sale cialis online order viagra here canadian viagra online best price cialis cialis online viagra store viagra online Low testosterone levels: Testosterone (the primary sex hormone in men) is not only necessary for sex drive (libido) but also is necessary to maintain nitric oxide levels in the penis. Therefore, men with hypogonadism (diminished function of the testes resulting in low testosterone production) can have low sex drive and erectile dysfunction. Vardenafil should not be used with alpha-blockers, medicines used to treat high blood pressure and benign prostate hypertrophy (BPH), because the combination of vardenafil and an alpha-blocker may lower the blood pressure greatly and lead to dizziness and fainting. Examples of alpha-blockers include tamsulosin (Flomax), terazosin (Hytrin), doxazosin (Cardura), alfuzosin (Uroxatral), and prazosin (Minipress).