Product Overview
Product name
Aijiu Sildenafil Citrate Tablets 50mg*6 tablets*2 plates
Product specifications
50mg*6 tablets*2 plates
Expiration date
24 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 Excipients include: microcrystalline cellulose, anhydrous calcium hydrogen phosphate, cross-linked carboxymethyl cellulose sodium, magnesium stearate and film coating premix.
Manufacturer
Jiangsu Wangao Pharmaceutical Co., Ltd.
[Usage and Dosage]
1. For most patients, the recommended dose is 50mg, taken as needed about 1 hour before sexual activity; but it can be taken at any time within 0.5 to 4 hours before sexual activity. Based on efficacy and tolerance, the dose can be increased to 100mg (maximum recommended dose) or reduced to 25mg. Take at most once a day. In the absence of sexual stimulation, the recommended dose of sildenafil is ineffective.
2. The following factors are associated with increased plasma sildenafil levels (AUC): age 65 years or older (increased by 40%), liver damage (such as cirrhosis, increased by 80%), severe renal impairment (creatinine clearance <30ml/min, increased by 100%), and concurrent use of potent cytochrome P4503A4 inhibitors [ketoconazole, itraconazole (increased by 200%), erythromycin (increased by 182%), saquinavir (increased by 210%)]. Since higher plasma levels may increase both efficacy and the incidence of adverse events, the starting dose for these patients is 25mg.
3. A study conducted in healthy subjects without HIV infection showed that Ritonavir can significantly increase sildenafil blood levels (AUC increased by 11 times, see "Drug Interactions"). See the inner package insert for details.
[Adverse Reactions]
The following are adverse events with an incidence of <2% in controlled clinical trials. It is not certain whether their occurrence is caused by sildenafil. 1 Events that may be related to medication are included here, but minor events and inaccurate reports are omitted.
1. Systemic reactions: facial edema, photosensitivity reaction, shock, fatigue, pain, chills, accidental falls, abdominal pain, allergic reaction, chest pain, accidental injury.
2. Cardiovascular system: angina pectoris, atrioventricular block, migraine, syncope, tachycardia, palpitations, hypotension, postural hypotension, myocardial ischemia, cerebral thrombosis, cardiac arrest, heart failure, abnormal electrocardiogram, cardiomyopathy.
3. Digestive system: vomiting, glossitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, dry mouth, abnormal liver function, rectal bleeding, gingivitis.
4. Blood and lymphatic system: anemia and leukopenia.
5. Metabolism and nutrition: thirst, edema, gout, unstable diabetes, hyperglycemia, peripheral edema, hyperuricemia, hypoglycemic reaction, hypernatremia.
6. Musculoskeletal system: arthritis, arthritis, myalgia, tendon rupture, tenosynovitis, bone pain, myasthenia, synovitis.
7. Nervous system: ataxia, hypertonia, neuralgia, neuropathy, paresthesia, tremor, vertigo, depression, insomnia, drowsiness, abnormal dreams, weakened reflexes, and dysesthesia.
8. Respiratory system: asthma, dyspnea, laryngitis, pharyngitis, sinusitis, bronchitis, sputum, and cough.
9. Skin and its appendages: urticaria. See the inner package insert for details.
[Contraindications]
Currently, there is no clinical controlled trial data on the safety and efficacy of sildenafil in the following populations. For such patients, prescriptions must be used with caution:
1. Patients who have had myocardial infarction, shock, or life-threatening arrhythmias in the last 6 months.
2. Patients with resting hypotension (blood pressure below 90/50 mmHg) or hypertension (blood pressure above 170/110 mmHg).
3. Patients with unstable angina due to heart failure or coronary heart disease.
4. Patients with pigmentary retinitis (a small number of patients with this disease have hereditary abnormalities of retinal phosphodiesterase).
5. Patients with sickle cell anemia or related anemia. See the inner package insert for details.
[Precautions] The interaction between sildenafil and nitrates affecting blood pressure can last from the start of administration to the entire 6-hour observation period. Therefore, in any case, the combined administration of sildenafil and organic nitrates or the provision of NO drugs (such as sodium nitroprusside) are contraindicated. Sildenafil should be used with caution in the following patients: patients with penile anatomical malformations (such as penile deviation, cavernous fibrosis, Peyronie's disease), and diseases that are prone to abnormal penile erections (such as sickle cell anemia, multiple myeloma, leukemia). The safety and effectiveness of other methods for the treatment of erectile dysfunction in combination with this product have not been studied, and combined use is not recommended. In the presence of existing cardiovascular risk factors, sexual activity after medication is at risk of non-fatal/fatal cardiac events. If you experience symptoms such as angina, dizziness, and nausea at the beginning of sexual activity, you must stop the sexual activity. After the product was 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 the erection lasts for more than 4 hours, the patient should seek medical attention immediately. If the abnormal erection is not treated immediately, the penile tissue may be damaged and may cause permanent loss of erectile function. Sildenafil has no protective effect against sexually transmitted diseases. See the inner package insert for details.
[Drugs for children] Sildenafil is not suitable for newborns and children.
[Drugs for elderly patients] The clearance rate of sildenafil in healthy elderly volunteers (≥65 years old) is reduced. The high blood drug concentration may also increase the occurrence of adverse events, so the starting dose is preferably 25mg.
[Drugs for pregnant and lactating women] Sildenafil is not suitable for women.
[Drug Interactions] Effects of other drugs on sildenafil: In vitro experiments: This product is metabolized mainly through cytochrome P4503A4 (main pathway) and 2C9 (minor pathway), so inhibitors of these isozymes will reduce the clearance of sildenafil. In vivo experiments: Healthy volunteers took 50 mg of this product and 800 mg of cimetidine (a non-specific cytochrome P450 inhibitor) at the same time, resulting in a 56% increase in the plasma concentration of sildenafil. When a single dose of sildenafil 100 mg is used in combination with erythromycin, a specific inhibitor of cytochrome P4503A4 (500 mg twice a day for 5 days to reach steady state), the area under the concentration-time curve (AUC) of sildenafil increases by 182%; when a single dose of sildenafil 100 mg is used in combination with saquinavir, another CYP4503A4 inhibitor, HIV protease inhibitor, to reach steady state (1200 mg three times a day), the Cmax of the latter increases by 140%, and the AUC increases by 210%. Sildenafil does not affect the pharmacokinetics of the latter; the above effects may be greater for more potent CYP4503A4 inhibitors such as ketoconazole and itraconazole; when used in combination with CYP4503A4 inhibitors (such as ketoconazole, erythromycin, cimetidine), the clearance rate of sildenafil decreases. See the inner package insert for details.
[Overdose] When drug overdose occurs, routine supportive therapy should be taken as needed. Because sildenafil has a high binding rate to plasma proteins, renal dialysis will not increase the clearance rate.
[Pharmacology and Toxicology] This product is an oral drug for the treatment of erectile dysfunction. It is the citrate of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific type 5 phosphodiesterase (PDE5). See the inner package insert for details.
[Pharmacokinetics] Sildenafil is rapidly absorbed after oral administration, with an absolute bioavailability of about 40%. Its pharmacokinetic parameters are proportional to the dose within the recommended dose range. Elimination is mainly through liver metabolism (cytochrome P450 isoenzyme 3A4 pathway), generating an active metabolite with properties similar to sildenafil. When potent inhibitors of cytochrome P450 isoenzyme 3A4 (CYP4503A4) (such as erythromycin, ketoconazole, itraconazole) and nonspecific inhibitors of cytochrome P450 (CYP450) such as cimetidine are used in combination with sildenafil, the plasma level of sildenafil may increase. The elimination half-life of sildenafil and its metabolites is about 4 hours. When 25-100 mg is given in the fasting state, the maximum plasma concentration (Cmax) of 127-560 ng/ml is reached in about 1 hour. The selectivity of sildenafil or its main metabolite N-desmethyl metabolite (N-desmethyl) for PDE5 is about 50%, and the protein binding rate is 96%. At the maximum plasma concentration of total sildenafil, the Cmax of free sildenafil is 22 ng/ml. After oral or intravenous administration, sildenafil is mainly excreted from feces in the form of metabolites (about 80% of the oral dose), and a small part is excreted from urine (about 13% of the oral dose). See the inner package insert for details.
