Product Overview
[Drug name]
Generic name: Sildenafil citrate tablets
Trade name: DuoHeiHei Sildenafil citrate tablets 50mg*6 tablets
Pinyin full code: DuoHeiHei ZuoZuoSuanXiDiNaFeiPian 5Omg*6Pian
[Main ingredients]
The main ingredients of this product are: Sildenafil citrate, its chemical name is: 1-{4-ethoxy-3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1hydro-pyrazolo[4,3d]pyrimidin-5-yl)benzenesulfonyl}-4-methylpiperazine citrate. Molecular formula: C22H30N6O4S·C6H8O7 Molecular weight: 666.70
[Properties]
This product is a blue film-coated tablet, which is white or off-white after removing the coating.
[Indications/Main Functions]
Sildenafil is suitable for the treatment of erectile dysfunction.
[Specifications]
50mg*6 tablets
[Dosage and Administration]
For most patients, the recommended dose is 50 mg, taken as needed approximately 1 hour before sexual activity; however, it can be taken at any time within 0.54 hours before sexual activity. Based on efficacy and tolerability, the dose can be increased to 100 mg (maximum recommended dose) or reduced to 25 mg. Take up to once a day. In the absence of sexual stimulation, the recommended dose of sildenafil does not work. The following factors are associated with increased plasma sildenafil levels (AU): age over 65 years (increase of 40%), liver damage (such as cirrhosis, increase of 80%), severe renal impairment (creatinine clearance <30 ml/min, increase of 100%), and concurrent use of potent cytochrome P4503A4 inhibitors (ketoconazole, itraconazole (increase of 200%), erythromycin (increase of 182%), saquinavir (increase of 210%)]. Since higher plasma levels may increase both efficacy and the incidence of adverse events, the starting dose for these patients is 25 mg. A study conducted in healthy subjects without HIV infection Studies have shown that ritonavir can significantly increase the blood level of sildenafil (AUC increased by 11 times, see [Drug Interactions]). In view of this, it is recommended that patients taking ritonavir at the same time should not take more than 2smg of the drug within 48 hours. Sildenafil can enhance the antihypertensive effect of nitrates, so patients taking any dosage form of nitric oxide donors and nitrates should not take sildenafil. When sildenafil needs to be used in combination with α-receptor blockers, the patient should have been treated with α-receptor blockers to achieve a stable state before sildenafil treatment, and sildenafil should be taken from the lowest dose (see [Drug Interactions]).
【Adverse Reactions】
See instructions for details.
[Contraindications]
Nitrates: Due to the known effects of this product on the nitric oxide/cGMP pathway (see [Pharmacology and Toxicology]), sildenaphine can enhance the antihypertensive effect of nitrates. Therefore, patients taking nitric oxide donors (such as any form of organic nitrates or organic nitrites), whether taking them regularly or intermittently, are contraindicated. It is not clear when patients can safely take nitrates (if necessary) after taking sildenafil. According to the pharmacokinetic data of healthy volunteers, a single oral dose of 100 mg will result in a plasma sildenafil concentration of approximately 2 ng/ml (peak blood drug concentration of approximately 440 ng/ml) 24 hours later (see [Pharmacology]). The following patients have plasma sildenafil concentrations 3-8 times higher than healthy volunteers 24 hours after taking the drug: those over 65 years old, those with liver damage (such as cirrhosis), those with severe renal damage (creatinine clearance below 30 ml/min), and those taking strong inhibitors of cytochrome P4503A4 such as erythromycin.Although sildenafil blood concentrations are far below peak concentrations 24 hours after dosing, it is not known whether nitrates can be safely taken at this time. Patients with known hypersensitivity to any of the ingredients in this product are contraindicated. Warning Cardiovascular: Sexual activity is potentially dangerous to the heart in patients with existing cardiovascular disease. Therefore, patients whose cardiovascular status is not suitable for sexual activity should generally not use drugs for the treatment of erectile dysfunction, including sildenafil. Sildenafil causes systemic vasodilation, resulting in a transient decrease in supine blood pressure in healthy volunteers (mean maximum decrease of 8.4/5.5 mmHg) (see [Pharmacology and Toxicology]). Usually in most patients, the consequences of this effect can be ignored, but physicians should still carefully consider whether this vasodilation effect will cause adverse consequences in patients with cardiovascular disease before prescribing, especially during sexual activity. Patients with the following underlying diseases may be particularly sensitive to the effects of vasodilators, including sildenafil - including left ventricular outflow tract obstruction (such as aortic stenosis, idiopathic hypertrophic subaortic stenosis) and diseases with severe impairment of autonomic control of blood pressure.Such patients should use the drug with caution. Currently, there is no clinical controlled trial data on the safety and efficacy of sildenafil in the following populations. Prescriptions should be made with caution for such patients: patients who have had myocardial infarction, shock or life-threatening arrhythmias in the last 6 months; patients with resting hypotension (blood pressure below 90/50 mmHg) or hypertension (blood pressure above 170/110 mmHg); patients with heart failure or unstable angina due to coronary heart disease; Prolonged erection and abnormal penile erection: After the product was approved for marketing abroad, there were a small number of reports of prolonged erection (more than 4 hours) and abnormal erection (painful erection for more than 6 hours).If an erection lasts for more than 4 hours, the patient should seek medical attention immediately. If abnormal erection is not treated immediately, penile tissue may be damaged and may lead to permanent loss of erectile function. This product should be used with caution in patients with the following diseases: penile anatomical malformations such as penile deviation, cavernous fibrosis, Peyronie's disease, and diseases that are prone to abnormal penile erection (such as sickle cell anemia, multiple myeloma, leukemia). However, there are currently no controlled clinical data on the safety or efficacy of this product in patients with sickle cell anemia or related anemias. Adverse reactions caused by co-administration with Ritonavir: Taking the protease inhibitor Ritonavir at the same time will significantly increase the blood concentration of sildenafil (AUC increased by 11 times). Sildenafil should be used with caution in patients taking Ritonavir. There is limited information on the effects of high blood concentrations of sildenafil on subjects, and it is only known that visual abnormalities are more common at high doses. Some healthy subjects taking high doses of sildenafil (200-800mg) reported decreased blood pressure, syncope, and prolonged erection. To reduce the likelihood of adverse events in patients taking Ritonavir, it is recommended to reduce the dose of sildenafil.
【Precautions】
General matters When diagnosing erectile dysfunction, its underlying cause should be identified, and appropriate treatment plans should be determined after a comprehensive medical examination. Before using sildenafil on patients, the following important issues should be noted: Hypotension when used in combination with alpha-blockers or antihypertensive drugs Alpha-blockers: PDE5 (phosphodiesterase type 5) inhibitors should be used with caution when used in combination with alpha-blockers. PDE5 inhibitors (including this product) and alpha-blockers are both vasodilators and have the effect of lowering blood pressure. When vasodilators are used in combination, it can be expected that the effects on blood pressure may be additive. In some patients, the combination of these two types of drugs can significantly lower blood pressure and cause symptoms of hypotension (such as dizziness, lightheadedness, and syncope) (see [Drug Interactions]). The following situations should also be noted: Before a patient receives sildenafil treatment, he should have reached a stable state of alpha-blocker treatment. Patients who take alpha-blockers alone to treat hemodynamic instability are at increased risk of hypotension symptoms after taking PDE5 inhibitors in combination. For patients who have achieved a stable state on alpha-blocker therapy, PDE5 inhibitors should be started at the lowest dose.- For patients already taking an optimal dose of a PDE5 inhibitor, alpha-blocker therapy should be initiated at the lowest dose. Co-administration of a PDE5 inhibitor may further reduce blood pressure as the alpha-blocker dose is increased. - The safety of combined use of PDE5 inhibitors and alpha-blockers may be affected by other factors, including insufficient intravascular volume and other antihypertensive medications. Antihypertensive medications: Sildenafil dilates systemic blood vessels and may enhance the antihypertensive effect of other antihypertensive medications. May be affected by other factors, including insufficient intravascular volume and other antihypertensive medications. Antihypertensive medications: Sildenafil dilates systemic blood vessels and may enhance the antihypertensive effect of other antihypertensive medications.Patients who were taking multiple antihypertensive drugs were included in the main clinical trials. Another independent drug interaction study showed that when sildenafil citrate tablets 100 mg were added to hypertensive patients taking 5 mg or 10 mg of amlodipine, systolic and diastolic blood pressures were further reduced by an average of 8 mmHg and 7 mmHg respectively (see [Drug Interactions]). In three drug interaction studies, patients with benign prostatic hyperplasia (BPH) who were stable on doxazosin therapy were also treated with the alpha-blocker doxazosin (4 mg and 8 mg) and sildenaphthene (25 mg, 50 mg or 100 mg). In these study populations, a further average reduction in supine blood pressure of 7/7 mmHg, 9/5 mmHg and 8/4 mmHg was observed, while a further average reduction in standing blood pressure of 6/6 mmHg, 11/4 mmHg and 4/5 mmHg respectively was observed. If a higher dose of sildenafil and doxazosin (4 mg) are taken simultaneously, there are reports of individual patients experiencing symptoms of orthostatic hypotension within 1 to 4 hours after taking the medication, including dizziness and lightheadedness, but without syncope.Patients treated with alpha-blockers while taking sildenafil may cause symptoms of hypotension in some patients. Therefore, sildenafil doses exceeding 25 mg should not be taken within 4 hours of taking alpha-blockers. Safety database analysis showed that there was no difference in side effects in patients taking sildenafil with or without antihypertensive drugs. In post-marketing experience, there have been reports of prolonged erections and abnormal erections associated with sildenafil. If an erection persists for more than 4 hours, the patient should seek medical attention immediately. If abnormal erections are not treated immediately, penile tissue may be damaged and may lead to permanent prolonged erections and reports of abnormal erections. If an erection persists for more than 4 hours, the patient should seek medical attention immediately.If priapism is not treated promptly, penile tissue may be damaged and may result in permanent prolonged erections and reports of priapism. If an erection persists for more than 4 hours, the patient should seek medical attention immediately. If priapism is not treated promptly, penile tissue may be damaged and may result in permanent loss of erectile function. Combination with other PDE5 inhibitors or other erectile dysfunction treatments: The safety and efficacy of other PDE5 inhibitors, or other pulmonary arterial hypertension (PAH) treatments containing sildenafil (Revatio), or other erectile dysfunction treatments have not been studied in combination with this product. Such combination therapy may further lower blood pressure. Therefore, combined use is not recommended.Effects on Bleeding: Post-marketing bleeding events have been reported in patients who have taken sildenafil citrate tablets. A causal relationship between this product and these events has not been established. Sildenafil citrate tablets have no effect on human bleeding time, whether used alone or in combination with aspirin. However, in vitro experiments, sildenafil citrate tablets enhance the anti-aggregation effect of sodium nitroprusside (a nitric oxide donor) on human platelets. In addition, in anesthetized rabbits, the combination of heparin and sildenafil has an additive effect on the prolongation of bleeding time, but similar human studies have not been conducted. The safety of sildenafil citrate tablets in patients with bleeding disorders and active peptic ulcers is currently unknown.Patient Information Physicians should explain to patients that sildenafil should not be taken with nitrates (regularly or intermittently). Physicians should inform patients that sildenafil has the potential to enhance the hypotensive effect of alpha-blockers and other antihypertensive drugs. Taking sildenafil and alpha-blockers together may cause hypotension in some patients. When sildenafil is used with alpha-blockers, patients should be stable on alpha-blocker therapy before sildenafil treatment, and sildenafil should be started at the lowest dose. Physicians should explain to patients that sexual activity has potential risks to the heart when cardiovascular risk factors are present. If symptoms such as angina, dizziness, and nausea occur at the beginning of sexual activity, sexual activity should be stopped and these conditions should be discussed with the doctor.Effects on the eyes: Physicians should inform patients that if they experience sudden vision loss in one or both eyes, they should immediately stop taking all phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil citrate tablets, and consult a physician. This condition may be a manifestation of non-arteritic anterior ischemic optic neuropathy (NAION), a disease that can cause vision loss, including permanent loss. Rare reports of NAION related to the duration of medication have been reported in all post-marketing applications of PDE5 inhibitors. An observational case-crossover study evaluated the risk of NAION when using PDE5 inhibitors just before the onset of NAION (within 5 half-lives) compared with the use of PDE5 inhibitors over a period of time. The results showed that the risk of NAION increased by approximately 2 times, with a risk estimate of 2.15 (95% CI 1.06, 4.34). A similar study reported consistent results, with a risk estimate of 2.27 (95% CI 0.99, 5.20). Other risk factors for NAION (such as optic disc "crowding") may be involved in the NAION that occurred in these studies.Rare post-marketing reports and observational studies of the association between PDE5 inhibitor use and NAION have not confirmed a causal relationship between PDE5 inhibitor use and NAION (see [Adverse Reactions]/Post-Marketing Experience). Published literature shows that in the general population, the annual incidence of NAION is 2.5 to 11.8 cases per 100,000 men (≥50 years old). If sudden vision loss occurs, patients should be advised to stop taking sildenafil and consult a physician immediately. For patients with potential NAION risk factors, doctors should consider whether they will be adversely affected by the use of PDE5 inhibitors. Individuals who have already experienced NAION have an increased risk of recurrence of NAION. Doctors should inform patients who have experienced unilateral NAION that their risk of recurring NAION is increased regardless of whether vasodilator drugs such as PDE5 inhibitors have adverse effects on them.In these patients, PDE5 inhibitors (including sildenafil) should be used with caution and only if the expected benefits outweigh the risks. Patients with "crowded" optic discs are also thought to have a higher risk of NAION than the general population, but evidence is insufficient to support screening potential users of PDE5 inhibitors (including this product) for this uncommon condition. There are no controlled clinical data on the safety or efficacy of this product in patients with retinitis pigmentosa (a small number of whom have a genetic disorder of retinal phosphodiesterase). It is not certain that these events are directly related to the use of PDE5 inhibitors or are related to other factors. Physicians should inform patients who have experienced unilateral NAION that they are at increased risk of another NAION regardless of whether vasodilator drugs such as PDE5 inhibitors may have adverse effects on them (see "Adverse Reactions/Postmarketing Experience/Special Sensations" section).Hearing loss: Doctors should inform patients that if hearing loss or loss occurs suddenly, they should stop taking PDE5 inhibitors (including this product) and seek medical attention as soon as possible. Such events may be accompanied by tinnitus and dizziness, and are reported to be time-related to the use of PDE5 inhibitors (including sildenafil citrate tablets). However, it is not certain whether such events are directly related to the use of PDE5 inhibitors or other factors (see [Adverse Reactions]/Pre-marketing Experience Section and Post-marketing Experience Section). Doctors should warn patients: After sildenafil citrate tablets were approved for marketing abroad, there were a small number of reports of prolonged erections (more than 4 hours) and abnormal erections (painful erections for more than 6 hours).If an erection persists for more than 4 hours, the patient should seek medical attention immediately. If priapism is not treated promptly, penile tissue may be damaged and permanent erectile dysfunction may result. Physicians should inform patients that this product should not be used with other PDE5 inhibitors. The safety and effectiveness of this product in combination with other PDE5 inhibitors have not been studied. Patient Counseling Regarding Sexually Transmitted Diseases: Sildenafil does not protect against sexually transmitted diseases. Patients should be informed of measures to prevent sexually transmitted diseases (including human immunodeficiency virus, HIV), as appropriate. Effects on the Ability to Drive and Use Machines Because dizziness and visual changes have been reported in clinical studies of sildenafil, patients should be informed of their possible reactions to sildenafil before driving and operating machines. The effects of sildenafil on the ability to drive and use machines have not been studied.
