Viagra 50mg Pfizer medicine for erectile dysfunction (1 blister x 1 tablet)

Dosage form Box of 1 blister x 1 tablet
Specifications Sildenafil

Ingredient

Composition information	Content
Sildenafil	50mg

Uses

indications

viagra medicine 50:

Sildenafil is used to treat erectile dysfunction, which is the inability to achieve or maintain enough erection to satisfy sexual activity.

Sildenafil only works when there is an accompanying sexual stimulation.

Pharmacological

Sildenafil has a selective inhibitory effect on Guanosine monophosphate (CGMP -CYClic guanosine monophosphate) - Phosphodiesterase specific type 5 (PDE5).

The penis physiological mechanism leads to the release of nitric oxid (NO) in the cave in the process of sexual stimulation. Then NO activated the Ganylat Cyclase yeast, this enzyme increases the concentration of CGMP, thereby relaxing the blood vessel smooth muscle of the cave and allows the blood flow to flow.

Sildenafil has no direct relaxation effect on human isolation, but it increases the effect of NO by inhibiting PDE5, this substance has the effect of decomposing CGMP in the cave. When sexual stimulation creates a NO release on the spot, Sildenafil's PDE5 inhibitors will increase the amount of CGMP in the cave, resulting in smooth muscle relaxation and increasing blood flow to the cave. In the recommended dose, Sildenafil only works when there is an accompanying sexual stimulation.

In vitro studies show that Sildenafil selectively inhibits PDE5. The effect of Sildenafil selected on PDE5 is stronger than the other known phosphodiesterase (10 times the PDE6,> 80 times for PDE1,> 700 times for PDE2, PDE3, PDE4 and PDE7- PDE11). Selective effect on PDE5 is 4,000 times stronger than PDE3, this is very important because PDE3 is a enzyme related to the contraction of the heart.

Dynamic pharmacokinetics

absorption: Sildenafil is quickly absorbed after drinking, with absolute bioavailability of about 41% (ranging from 25-63%). Food with high fat content reduces Sildenafil's absorption.

Distribution: Sildenafil's average drug distribution is 105 l, focusing on tissues. Sildenafil and the metabolites in its large circulatory round are N-Desmethyl mounted up to 96% to plasma proteins. The attachment to plasma protein does not depend on its total concentration.

Metabolism:

Sildenafil is metabolized mainly by CYP3A4 (main roads) and CYP2C9 (sub -line) in the liver. The metabolites in Sildenafil's main metabolism generated from the n-de-methylation process, and then continued to be metabolized again. In healthy volunteers, the plasma concentration of metabolites is approximately 40% of the mother concentration. N-Desmethyl metabolites are metabolized again, with a half-life of 4 hours.

Elimination: The total clearance of Sildenafil is 41 l/h with half phase time of 3-5 hours. After oral or intravenous use, Sildenafil is excreted mainly in the form of metabolic (about 80% of oral dose) and a small part through the urine (about 13% of oral dose).

Before taking Viagra 50mg Pfizer medicine for erectile dysfunction (1 blister x 1 tablet)

How to use

Sildenafil tablets are used by oral.

Dosage

For adults: Most patients are recommended to take the dose of 50 mg when needed, take before sex about 1 hour. Based on the tolerance and effect of the drug, the dose may increase to a maximum of 100 mg or decrease to 25 mg. The maximum recommended dose is 100 mg, the maximum number of times is 1 time per day.

For patients with renal failure: Cases of mild or medium renal failure (creatinine clearance = 30-80 ml/minute), do not need to adjust the dose. Cases of severe renal failure (Creatinine clearance For patients with liver failure: The dose should be used as 25 mg because the clearance of Sildenafil is reduced in these patients (for example, cirrhosis).

For patients who are taking other drugs, based on the degree of interaction in patients taking Sildenafil simultaneously with Ritonavir, it should not exceed a maximum single dose of 25 mg Sildenafil within 48 hours. Patients who are taking drugs inhibit CYP3A4 (for example, erythromycin, saquinavir, ketoconazole, iTraconazole), the starting dose should be used as 25 mg. To limit the risk of posture hypotension during treatment, patients should be stable treatment when using sympathetic cancellation drugs before starting treatment with Sildenafil. In addition, it is advisable to consider using lower Sildenafil doses at the beginning of treatment.

For children: Do not use Sildenafil for children under 18 years old.

For the elderly: No need to adjust the dose.

Note: The above dose is for reference only. Specific dosage depends on the condition and level of progression of the disease. For a suitable dose, you need to consult a doctor or medical specialist.What to do when using overdose?

What to do when you forget a dose? However, if close to the next dose, skip the forgotten dose and take the next dose at the time as planned. Note that it should not be used double the prescribed dose.

Side Effects

When using Viagra 50, you may experience unwanted effects (ADR).

Common, ADR> 1/100

Neurological: headache, dizziness.

digestive: nausea, indigestion.

Eyes: blurred vision, disorder, evidence of green.

circuit: flushing.

Respiratory: stuffy nose.

Uncommon, 1/1000

Body: Hypersensitivity.

Neurological: Drowsy. digestive: vomiting, abdominal pain, dry mouth.

eyes: eye pain, fear of light, dizziness, eye congestion.

cardiovascular: tachycardia, brushing chest drum, lowering blood pressure.

Instructions on how to handle ADR

When experiencing side effects of the drug, it is necessary to stop using and notify the doctor or go to the nearest medical facility for timely treatment.

Warnings

Before using the drug you need to read the instructions carefully and refer to the information below.

Contraindications:

Viagra 50 drugs contraindicated in the following cases:

For patients allergic to any component of the drug.

Sildenafil increases the hypotension effect of acute and chronic nitrates. So contraindicated use of Sildenafil for patients who are using nitric oxide suppliers, organic nitrates or organic nitrites in any form, whether they are frequent or interrupted.

Be cautious when using

must exploit prehistoric and meticulous clinical examination to diagnose erectile dysfunction, to identify hidden causes and determine appropriate treatment. Because there may be some cardiovascular risks associated with sexual activity, the physician must pay attention to the patient's cardiovascular condition before conducting erectile dysfunction treatment.

Do not use erectile dysfunction drugs in men are recommended not to be sexually active. Serious cardiovascular events include myocardial infarction, sudden death related to heart disease, ventricular arrhythmia, cerebral hemorrhage and transient ischemic anemia reported during the circulation using Sildenafil to treat erectile dysfunction. Some clinical trials show that Sildenafil has a systemic vasodilation attribute that causes fleeting hypotension.

Patients who hinder the left ventricular flow (for example, aortic stenosis, obstructive hypertrophy of myocardial disease) or a multiple system of multiple system Atrophy (patients with patients with hyperactive hyperplasia, manifested by a serious decline in the ability to control blood pressure automatically, those who need to be considered for treatment.

Non -artery anemia neuropathy, a rare disease and is the cause of vision loss or vision loss, is reported rare during circulation when used with phosphodiesterase inhibitors in group 5 (PDE5), including Sildenafil.

Be careful when indicating Sildenafil for patients who are taking sympathetic drugs because they can lead to symptomic hypotension in sensitive patients.

A few patients with pigmentation retinitis have phosphodiesterase gene disorders in the retina, need to be cautious when treating Sildenafil in these patients because there is no safety evidence.

There is no safe information about the use of Sildenafil in patients with acute blood clotting or digestive ulcers, so be cautious in these patients. Be careful when prescribing erectile dysfunction agents for patients with penile anatomical deformations, patients with pathological diseases that can cause erectile dysfunction. There has been a report on prolonged erection and unwanted erection when using Sildenafil after the drug is circulated.

Safety and effectiveness of using Sildenafil combining with other PDE5 inhibitors, pulmonary arterial medications (PAH) contains Sildenafil (Revatio) or other non -researched erectile dysfunction drugs, so it should not be combined with these drugs.

Sudden reduction or loss of hearing has been reported on a small number of cases using PDE5 inhibitors, including Sildenafil.

The ability to drive and operate machinery

There has been no specific research on the effects of driving and operating machinery. The phenomenon of headache, dizziness and vision change has been reported in clinical trials with Sildenafil, so patients need to know how they react to Viagra before driving or operating the machine.

Pregnancy

There are no complete and appropriate studies in pregnant women.

The period of breastfeeding

There are no adequate and appropriate studies in breastfeeding women.

Interaction

Sildenafil has been shown to be able to increase the impact of hypotension of acute and chronic nitrate drugs.

Sildenafil metabolic in vitro studies take place mainly by cytochrome P450 (CYP) groups form 3A4 (main road) and 2C9 (sub -line). Therefore, all agents that inhibit CYP3A4 (such as ketoconazole, erythromycin, cimetidine, protease inhibitors of HIV) will reduce Sildenafil's clearance.

Storage

In a dry place, avoid light, temperatures below 300C.

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