Cialis (tadalafil) vs. Levitra (vardenafil)

Tadalafil is a phosphodiesterase-5 (PDE5) inhibitor used to treat impotence and benign prostatic hyperplasia (BPH). Other PDE5 inhibitors include sildenafil (Viagra) and vardenafil (Levitra). Sexual stimulation causes the production and release of nitric oxide in the penis, which leads to the enzyme guanylate cyclase producing cyclic guanosine monophosphate (cGMP). cGMP increases and decreases the size of blood vessels carrying blood to and from the penis, causing an erection. Tadalafil prevents PDE5 from destroying cGMP, resulting in a more prolonged erection. It is unclear how tadalafil improves BPH symptoms, but it is believed to relax the muscles of the bladder and prostate, reducing pressure in the muscle controlling urine flow.

Vardenafil is a PDE5 inhibitor used to treat impotence. It has a mechanism of action similar to sildenafil and tadalafil. Penile erection is caused by increased blood flow to the penis and decreased blood flow away from the penis. Sexual stimulation causes the production and release of nitric oxide, activating the enzyme guanylate cyclase to produce cGMP. Vardenafil prevents the enzyme phosphodiesterase-5 (PDE-5) from destroying cGMP, prolonging the engorgement of the penis.

Side effects of tadalafil and vardenafil

Tadalafil

The most common side effects of tadalafil include facial flushing, headaches, stomach upset, diarrhea, flu-like symptoms, nausea, low blood pressure, blurred vision, changes in color vision, and abnormal ejaculation.

Vardenafil

The most common side effects of vardenafil include facial flushing, headaches, stomach upset, diarrhea, flu-like symptoms, nausea, chest pain, low blood pressure, blurred vision, changes in color vision, abnormal ejaculation, and priapism (painful erection lasting more than 6 hours).

Dosage for tadalafil vs. vardenafil

Tadalafil

The recommended starting dose of tadalafil is 10 mg per day before sexual activity. Depending on the response or side effects, the dose may be increased to 20 mg or decreased to 5 mg a day. The effect of tadalafil may last up to 36 hours. For once daily use without regard to sexual activity, the recommended dose is 2.5 to 5 mg daily. The recommended dose for BPH or BPH and ED is 5 mg daily. Tadalafil should not be taken more than once daily.

The dose of tadalafil may require adjustment for patients with reduced kidney or liver function.

Vardenafil

The recommended dose of vardenafil regular tablets is 10 mg per day taken 60 minutes before intercourse. The dose may be increased to 20 mg or reduced to 5 mg based on response or side effects. Individuals 65 years of age or older should start therapy with 5 mg. Individuals taking medications that increase blood levels of vardenafil should start treatment with 2.5 to 5 mg. Orally disintegrating tablets (ODT) should be taken one tablet 60 minutes before intercourse.

Drug interactions with tadalafil and vardenafil

Tadalafil

The breakdown and elimination of tadalafil from the body may be decreased by certain drugs, which may increase its levels. Rifampin, carbamazepine, phenytoin, and phenobarbital may decrease blood levels of tadalafil. Tadalafil should not be used with nitrates or alpha-blocking drugs for BPH treatment. Tadalafil and alcohol may cause excessive drops in blood pressure. Tadalafil should not be combined with Adcirca or other PDE5 inhibitors.

Vardenafil

The breakdown and elimination of vardenafil from the body is inhibited by certain drugs, increasing its concentration. Vardenafil should not be combined with erythromycin, clarithromycin, ketoconazole, itraconazole, indinavir, ritonavir, atazanavir, or grapefruit juice. Vardenafil increases heart rate and exaggerates the blood pressure lowering effects of nitrates and alpha-blocking drugs. Vardenafil should not be used by patients with angina or those taking alpha-blockers.

Safety during pregnancy or breastfeeding

Tadalafil

Tadalafil is not approved for use in women and has not been evaluated in women who are breastfeeding.

Vardenafil

Vardenafil is not approved for use in women and has not been evaluated in women who are breastfeeding.

Summary

Cialis (tadalafil) and Levitra (vardenafil) are PDE5 inhibitors used to treat impotence. Tadalafil is also used to treat symptoms of BPH.