Product Overview
Product name
Langmei Dongyangguang Sildenafil Citrate Tablets 100mg*5 tablets*1 plate
Product specifications
100mg*5 tablets*1 plate
Expiration date
36 months
Main raw materials
The main ingredient of this product is sildenafil citrate. Chemical name: 1-{4-ethoxy-3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1hydrogen-pyrazolo［4,3d］pyrimidin-5-yl)benzenesulfonyl}-4-methylpiperazine citrate. Molecular formula: C22H30N6O4S. C6H8O7 Molecular weight: 666.70
Manufacturer
Guangdong Dongyangguang Pharmaceutical Co., Ltd.
General matters When diagnosing erectile dysfunction, its underlying cause should be identified and appropriate treatment should be determined after a comprehensive medical examination. Before using sildenafil on patients, it is important to note the following important issues:
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 fainting) (see [Drug Interactions]).
The following should also be noted:
– Patients should have reached a stable state on alpha-blocker therapy before receiving sildenafil. Patients who are hemodynamically unstable and are taking alpha-blockers alone are at increased risk of developing hypotension symptoms after taking PDE5 inhibitors. – Patients who have reached a stable state on alpha-blocker therapy should start taking PDE5 inhibitors at the lowest dose. – For patients who are already taking the ideal dose of PDE5 inhibitors, alpha-blocker therapy should be started at the lowest dose. The simultaneous use of PDE5 inhibitors may further lower blood pressure as the dose of alpha-blockers is gradually increased. – The safety of the combined use of PDE5 inhibitors and alpha-blockers may be affected by other factors, including insufficient intravascular volume and other antihypertensive drugs.
Antihypertensive drugs: Sildenafil dilates systemic blood vessels and may enhance the antihypertensive effect of other antihypertensive drugs.
Patients taking multiple antihypertensive drugs were included in the main clinical trials. Another independent drug interaction study showed that when hypertensive patients taking 5mg or 10mg amlodipine added 100mg of sildenafil citrate tablets, systolic and diastolic blood pressures were further reduced by an average of 8mmHg and 7mmHg respectively (see [Drug Interactions]).
In three drug interaction studies, patients with benign prostatic hyperplasia (BPH) who were stable on doxazosin treatment took the alpha-blocker doxazosin (4mg and 8mg) and sildenafil (25mg, 50mg or 100mg) at the same time. In these study populations, supine blood pressure was observed to be further reduced by an average of 7/7mmHg, 9/5mmHg and 8/4mmHg, respectively, while standing blood pressure was further reduced by an average of 6/6mmHg, 11/4mmHg and 4/5mmHg respectively. If a higher dose of sildenafil is taken at the same time as doxazosin (4 mg), individual patients have reported symptoms of postural hypotension within 1 to 4 hours after taking the drug, including dizziness and lightheadedness, but without syncope. Patients treated with alpha-blockers taking sildenafil at the same time 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 shows that there is 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 lasts 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 permanent erectile dysfunction may occur. 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 combined with this product have not been studied. Such combined use may further lower blood pressure. Therefore, combined use is not recommended.
Effect 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, 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 (regardless of whether the latter are taken regularly or intermittently).
Physicians should inform patients that sildenafil has the potential to enhance the antihypertensive effect of alpha-blockers and other antihypertensive drugs. Taking sildenafil and alpha-blockers together may cause hypotension in some patients. When sildenafil is used in combination with alpha-blockers, patients should have reached a stable state of alpha-blocker treatment before sildenafil treatment, and sildenafil should be started at the lowest dose.
Physicians should explain to patients that sexual activity is potentially dangerous 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 situations should be discussed with the doctor.
Effects on the eyes: Physicians should inform patients that if sudden vision loss occurs in one or both eyes, they should immediately stop taking all phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil citrate tablets, and consult a doctor. This situation 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 medication time 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 the association between PDE5 inhibitor use and NAION in observational studies have not confirmed a causal relationship between PDE5 inhibitor use and NAION (see [Adverse Reactions]/Post-Marketing Experience). Published literature data show 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. Physicians should consider whether patients with potential risk factors for NAION may be adversely affected by the use of PDE5 inhibitors. Individuals who have already experienced NAION are at increased risk for recurrence of NAION. Physicians should advise patients who have experienced unilateral NAION that they are at increased risk for recurrence of NAION regardless of whether vasodilator medications such as PDE5 inhibitors would adversely affect 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, however, there is insufficient evidence 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 for patients with retinitis pigmentosa (a small number of whom have genetic diseases of retinal phosphodiesterase).
It cannot be determined whether 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 their risk of recurrence of NAION is increased regardless of whether vasodilators such as PDE5 inhibitors have adverse effects on them (see "Adverse Reactions/Post-Marketing 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 the approval of sildenafil citrate tablets abroad, there have been a small number of reports of prolonged erections (more than 4 hours) and abnormal erections (painful erections for more than 6 hours). If the erection lasts 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 cause permanent loss of erectile function.
Physicians should inform patients that this product should not be used with other PDE5 inhibitors. The safety and efficacy of this product in combination with other PDE5 inhibitors have not been studied.
Patient Counseling Advice 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 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.
