Viasan-LF, 50 mg 4 pcs

A product for the treatment of erectile dysfunction. It restores impaired erectile function and provides a natural response to sexual arousal.

Sildenafil is a potent and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5), which is responsible for breakdown of cGMP in the corpora cavernosa. Sildenafil does not have a direct relaxing effect on the cavernous body, but it actively enhances the relaxing effect of nitric oxide on this tissue.

In sexual arousal, local release of NO under the influence of sildenafil leads to inhibition of FDE5 and increase of cGMP level in the corpora cavernosa, as a result of this there is relaxation of smooth muscles and increase of blood flow in the corpora cavernosa.

Sildenafil can cause mild and transient color (blue/green) impairment. The inhibition of FDE6, which is involved in the transmission of light in the retina, is thought to be the presumed mechanism of color vision impairment. In vitro studies have shown that the effect of sildenafil on FDE6 is 10 times inferior to its activity against FDE5.

In vitro studies show that sildenafil’s activity against FDEP5 is 10-10000 times greater than its activity against other phosphodiesterase isoforms (FDEP 1, 2, 3, 4 and 6). In particular, sildenafil activity against FDE5 is 4,000 times higher than its activity against FDE3 – cAMP-specific phosphodiesterase involved in heart contraction.

Indications

The treatment of erectile dysfunction characterized by the inability to achieve or maintain an erection of the penis sufficient for satisfactory intercourse.

Active ingredient

Composition

Periodic film-coated tablets.

Sildenafil (in citrate form) 50 or 100 mg

How to take, the dosage

It is taken orally about 1 hour before planned sexual activity.

The single dose is 50 mg.

The dose may be increased to 100 mg or decreased to 25 mg, depending on effectiveness and tolerability.

The maximum single dose is 100 mg.

The maximum frequency of use is once daily.

For elderly patients over 65 years of age and with concomitant renal or hepatic dysfunction, the dose is 25 mg.

Interaction

Concomitant use of CYP3A4 inhibitors (erythromycin, cimetidine) decreases sildenafil clearance and increases sildenafil plasma concentration.

Concomitant use of indinavir, saquinavir, ritonavir increases plasma Cmax and AUC of sildenafil due to inhibition of CYP3A4 isoenzyme by indinavir, saquinavir, ritonavir.

The stronger CYP3A4 isoenzyme inhibitors, such as ketoconazole or itraconazole, can be expected to increase plasma concentrations of sildenafil

Simultaneous use with nitrates increases the hypotensive effect of nitrates.

A case of development of rhabdomyolysis symptoms after a single dose of sildenafil in a patient receiving simvastatin has been described.

Special Instructions

An examination of the cardiovascular system should be performed before starting sildenafil.

With caution, use in patients with anatomical deformities of the penis (e.g., angulation, cavernous fibrosis, or Peyronie’s disease) and people with diseases that predispose to the development of priapism (such as sickle cell anemia, multiple myeloma, or leukemia).

Do not use in patients for whom sexual activity is undesirable.

With caution, use in patients with a tendency to bleeding, in the acute phase of gastric and duodenal ulcer, in hereditary retinitis pigmentosa.

There is no evidence of carcinogenicity of sildenafil in experimental studies. Bacterial and in vivo mutagenicity tests were negative.

Influence on driving and operating ability

Sildenafil has no effect on driving and operating ability.

In impaired renal function

In impaired renal function, the dose is 25 mg.

In impaired liver function

In impaired liver function, the dose is 25 mg.

Application in the elderly

For elderly patients over 65 years of age, the dose is 25 mg.

Application in children.

Sildenafil is not used in patients under 18 years of age.

Contraindications

Simultaneous use of nitric oxide donors or nitrates in any form, hypersensitivity to sildenafil.

Side effects

CNS disorders: headache, hot flashes, dizziness, insomnia are possible.

Digestive system disorders: dyspepsia, asthenia, diarrhea, abdominal pain, nausea are possible.

Muscular system disorders: arthralgia, myalgia, increased muscle tone.

Respiratory system disorders: nasal congestion, pharyngitis, rhinitis, sinusitis, respiratory tract infections, respiratory disorders.

A visual organ: changes in vision (mild and transient; mainly changes in the color of objects, as well as increased perception of light and impaired visual clarity), conjunctivitis.

Others: flu-like syndrome, development of infectious diseases, symptoms of vasodilation, back pain, rash, urinary tract infections, prostate disorders; in single cases – priapism.

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