Expiration date: 06/2025
Structure and Composition
Sildenafil tablets, coated
1 tablet contains sildenafil (as citrate), 50 and 100 mg,
4 per pack and 10 pcs.
Pharmachologic effect
Drug for the treatment of erectile dysfunction. Sildenafil citrate is a potent and selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5).
The physiological mechanism of erection of the penis involves the release of nitric oxide (NO) in the cavernous body during sexual stimulation.
Nitric oxide activates guanylate cyclase enzyme, which results in increased levels of cyclic guanosine monophosphate (cGMP), relaxation of the corpus cavernosum smooth muscle and increased blood flow to the penis.
Sildenafil has no direct relaxing effect on isolated human corpus cavernosum body, but actively enhances the relaxing effect of NO on this tissue by inhibiting PDE5, which is responsible for the breakdown of cGMP in the cavernous body.
When sexual stimulation, local release of NO under the influence of Sildenafil PDE5 results in inhibition and increased levels of cGMP in the cavernous body, resulting in smooth muscle relaxation and increased blood flow to the cavernous body.
Sildenafil at recommended doses ineffective in the absence of sexual stimulation.
Sildenafil, indications for use
Erectile dysfunction characterized by the inability to achieve or retain an erection of the penis sufficient for satisfactory sexual akta.Preparat Viagra is effective only if there is sexual stimulation.
Contraindications
- Hypersensitivity to the drug.
The drug is contraindicated in patients receiving either permanently or intermittently donator of nitric oxide, organic nitrates or nitrates in any form as sildenafil enhances the hypotensive effect of nitrates taken continuously or in an emergency.
Pregnancy and breast-feeding
Sildenafil is not intended for use in women.
Adequate and well-controlled trials in pregnancy and lactation in women was conducted.
Dosing and Administration
The drug is taken orally.
For most patients, the recommended dose is 50 mg, the drug is taken when needed for approximately 1 hour prior to sexual activity. Given the efficacy and tolerability of the dose can be increased to 100 mg or decreased to 25 mg.
The maximum recommended multiplicity of application - 1 time / day.
In applying the drug in patients aged over 65 years, patients with impaired hepatic function, patients with severe renal insufficiency and in patients receiving concomitant medications - inhibitors of CYP3A4 of cytochrome P450 (eg, erythromycin, saquinavir), there is an increase sildenafil levels plasma, which can help increase the effectiveness of the drug, and the possibility of side effects. It can be expected that even more potent inhibitors of CYP3A4 isoenzyme of cytochrome P450, such as ketoconazole or itraconazole, may lead to increased levels of sildenafil in plasma. It discuss the relevance of drug administration at a dose of 25 mg / day in these groups of patients.
The drug is not intended for use in patients under the age of 18 years.
Side effects
On the part of the body as a whole: asthenia, pain, abdominal pain, back pain, infection, flu-like symptoms.
Cardio-vascular system: vasodilation (side effect reported in clinical studies).
From the digestive system: diarrhea, nausea.
From the musculoskeletal system: joint pain, muscle pain.
From the central and peripheral nervous system: dizziness (side effect reported in clinical studies), increased muscle tone, insomnia.
The respiratory system: nasal congestion, pharyngitis, rhinitis (side effect reported in clinical studies), sinusitis, respiratory tract infection, respiratory failure function.
Dermatological reactions: rash.
From the senses: vision changes: mild and transient, mostly change the color of objects, as well as increased perception of light and blurred vision (side effect reported in clinical studies), conjunctivitis.
From the urinary system: urinary tract infection.
From the reproductive system: violation of the prostate gland.
When using the drug in doses than recommended, the side effects were similar to the above, but more commonly encountered.
Listed below are adverse events recorded during the post-marketing use.
Since the cardiovascular system: hypotension, syncope, tachycardia, palpitation.
From the digestive system: vomiting (side effect reported in clinical studies).
From the reproductive system: prolonged erection and / or priapism.
From the senses: eye pain, eye redness.
Other: allergic reactions.
Side effects were generally transient and mild or moderate in intensity.
In studies with fixed doses of incidence of side effects increased with increasing dose.
The nature of side effects in studies in which the dose was adjusted, since such studies to better reflect the recommended application scheme was comparable to that in the fixed-dose studies.
Drug interactions
A single dose of antacid (magnesium hydroxide / aluminum hydroxide) in conjunction with sildenafil did not affect the bioavailability. It enhances the hypotensive effect of nitrates (concomitant use is contraindicated) and antiplatelet effect of sodium nitroprusside. When concomitantly with acetylsalicylic acid (150 mg) did not increase bleeding time. CYR3A4 inhibitors (. Cimetidine, ketoconazole, itraconazole, erythromycin and others) to the concentration of sildenafil in the plasma (in particular cimetidine 800 mg - 56%, when taking sildenafil, 50 mg) and reduce its excretion. In single dose of 100 mg sildenafil on the background of the equilibrium concentration of erythromycin (receiving 500 mg twice daily for 5 days) AUC sildenafil increased by 182%, on the background of the equilibrium concentration of saquinavir (1200 mg 3 times daily) Cmax of sildenafil increased by 140% , AUC - 210%. A single dose of 100 mg sildenafil on the background of the equilibrium concentration of ritonavir - a potent inhibitor of cytochrome P450 (400 mg, 2 times daily) results in 4-fold (300%) increase Cmax and 11-fold (1000%) increase AUC sildenafil. Sildenafil has no effect on the pharmacokinetics of ritonavir and saquinavir. CYP2C9 inhibitors (tolbutamide, warfarin) of CYP2D6 (selective serotonin reuptake inhibitors, tricyclic antidepressants), thiazides and thiazide diuretics, loop and potassium-sparing diuretics, ACE inhibitors, calcium channel blockers, beta-blockers and inducers of cytochrome P450 (rifampicin, barbiturates) do not have effect on the pharmacokinetics of sildenafil. It is assumed that while taking sildenafil with inducers of CYP3A4 (rifampicin, etc.), Its plasma concentration will decrease. AUC of the active metabolite of sildenafil is increased by 62% when receiving loop and potassium-sparing diuretics and 102% - when receiving nonspecific beta-blockers (the clinical significance of these effects is not defined). There were no signs of interaction with amlodipine (5 mg and 10): the average additional reduction in blood pressure in the supine position (Sad to 8 mmHg DBP 7 mm Hg) is comparable to that when receiving one of sildenafil in healthy volunteers. Not enhances the hypotensive effect of alcohol in healthy volunteers with a blood alcohol concentration of up to 80 mg / dL.
Overdose
Symptoms in studies in healthy volunteers with single dose of 800 mg sildenafil noted increased severity of side effects.
Treatment: symptomatic. Dialysis is ineffective because of the high degree of binding of sildenafil and its metabolite plasma proteins.
Storage conditions
The drug should be stored at room temperature (15 ° to 30 ° C).
* The appearance of the packaging may vary from photo
