Introduction
Varda Tablet 20 mg (Levitra) is an oral therapy for the treatment of erectile dysfunction. It is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5). Penile erection is a hemodynamic process initiated by the relaxation of smooth muscle in the corpus cavernosum and its associated arterioles. During sexual stimulation, nitric oxide is released from nerve endings and endothelial cells in the corpus cavernosum. Nitric oxide activates the enzyme guanylate cyclase resulting in increased synthesis of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum. The cGMP in turn triggers smooth muscle relaxation, allowing increased blood flow into the penis, resulting in erection. The tissue concentration of cGMP is regulated by both the rates of synthesis and degradation via phosphodiesterases (PDEs). The most abundant PDE in the human corpus cavernosum is the cGMPspecific phosphodiesterase type 5 (PDE5); therefore, the inhibition of PDE5 enhances erectile function by increasing the amount of cGMP.
Uses
Varda Tablet 20 mg is a phosphodiesterase 5 inhibitor used to treat erectile dysfunction.
Used for the treatment of erectile dysfunction
Associated Conditions
Pharmacodynamics
Varda Tablet 20 mg is used to treat male erectile dysfunction (impotence) and pulmonary arterial hypertension (PAH). Part of the physiological process of erection involves the release of nitric oxide (NO) in the corpus cavernosum. This then activates the enzyme guanylate cyclase which results in increased levels of cyclic guanosine monophosphate (cGMP), leading to smooth muscle relaxation in the corpus cavernosum, resulting in increased inflow of blood and an erection. Varda Tablet 20 mg is a potent and selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernosum. This means that, with vardenafil on board, normal sexual stimulation leads to increased levels of cGMP in the corpus cavernosum which leads to better erections. Without sexual stimulation and no activation of the NO/cGMP system, vardenafil should not cause an erection.
Mechanism of Action
Varda Tablet 20 mg inhibits the cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernosum located around the penis. Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and corpus cavernosal smooth muscle. This response is mediated by the release of nitric oxide (NO) from nerve terminals and endothelial cells, which stimulates the synthesis of cGMP in smooth muscle cells. Cyclic GMP causes smooth muscle relaxation and increased blood flow into the corpus cavernosum. The inhibition of phosphodiesterase type 5 (PDE5) by vardenafil enhances erectile function by increasing the amount of cGMP.
Absorption
Varda Tablet 20 mg is rapidly absorbed with absolute bioavailability of approximately 15%.
Volume of Distribution
- 208 L
Protein Binding
95%
Route of Elimination
After oral administration, vardenafil is excreted as metabolites predominantly in the feces (approximately 91-95% of administered oral dose) and to a lesser extent in the urine (approximately 2-6% of administered oral dose).
Half Life
4-5 hours
Clearance
- 56 L/h
Toxicity
Symptoms of overdose include vision changes and back and muscle pain.
Food Interactions
- Avoid grapefruit products. Varda Tablet 20 mg is metabolized by CYP3A4, and grapefruit products are CYP3A4 inhibitors; therefore, coadministration may increase serum levels of vardenafil and result in increased hypotension. .
- Take with or without food.
Dosage
Geriatrics: A starting dose of 5 mg should be considered in patients >65 years of age.
Renal impaired patients: In patients with renal impairment, no dose adjustment is required.
Hepatic impaired patients: In patients with moderate hepatic impairment, a starting dose of 5 mg is recommended and the maximum dose should not exceed 10 mg. Do not use in patients with severe hepatic impairment.
