6. ADVERSE REACTIONS

The following adverse reactions have been identified during post approval use of sildenafil citrate. These events have been chosen for inclusion either due to their seriousness, reporting frequency, lack of clear alternative causation, or a combination of these factors. Serious cardiovascular, cerebrovascular, and vascular events, including myocardial infarction, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, transient ischemic attack, hypertension, subarachnoid and intracerebral hemorrhages, and pulmonary hemorrhage have been reported post-marketing in temporal association with the use of sildenafil citrate.

It is not possible to determine whether these events are related directly to sildenafil citrate, to sexual activity, to the patient’s underlying cardiovascular disease, to a combination of these factors, or to other factors [ see Warnings and Precautions (5.1)and Patient Counseling Information (17)]. Hemic and Lymphatic:vaso-occlusive crisis: In a small, prematurely terminated study of sildenafil tablets, 20 mg (sildenafil) in patients with pulmonary arterial hypertension (PAH) secondary to sickle cell disease, vaso-occlusive crises requiring hospitalization were more commonly reported in patients who received sildenafil than in those randomized to placebo. The clinical relevance of this finding to men treated with sildenafil tablets, 25 mg, 50 mg and 100 mg for ED is not known. Nervous:seizure, seizure recurrence, anxiety, and transient global amnesia. Hearing:Cases of sudden decrease or loss of hearing have been reported postmarketing in temporal association with the use of PDE5 inhibitors, including sildenafil citrate. It is not possible to determine whether these reported events are related directly to the use of sildenafil citrate, to the patient’s underlying risk factors for hearing loss, a combination of these factors, or to other factors [ see Warnings and Precautions (5.4)and Patient Counseling Information (17)].

What is sildenafil?

Ocular:diplopia, temporary vision loss/decreased vision, ocular redness or bloodshot appearance, ocular burning, ocular swelling/pressure, increased intraocular pressure, retinal edema, retinal vascular disease or bleeding, and vitreous traction/detachment. Non-arteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision, has been reported rarely post-marketing in temporal association with the use of phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil citrate.

Most, but not all, of these patients had underlying anatomic or vascular risk factors for developing NAION, including but not necessarily limited to: low cup to disc ratio (“crowded disc”), age over 50, diabetes, hypertension, coronary artery disease, hyperlipidemia and smoking [ see Warnings and Precautions (5.3)and Patient Counseling Information (17)]. Urogenital:prolonged erection, priapism [ see Warnings and Precautions (5.2)and Patient Counseling Information (17)], and hematuria. 7 DRUG INTERACTIONS 7.1 NitratesAdministration of sildenafil citrate with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. Consistent with its known effects on the nitric oxide/cGMP pathway, sildenafil citrate was shown to potentiate the hypotensive effects of nitrates [ see Dosage and Administration (2.3), Contraindications (4.1), sildenafil oral jelly 100 mg Clinical Pharmacology (12.2)].7.2 Alpha-blockersUse caution when co-administering alpha-blockers with sildenafil citrate because of potential additive blood pressure-lowering effects.

In-Depth Details for Importers, Exporters, and Buyers

When sildenafil citrate is co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil citrate treatment and sildenafil citrate should be initiated at the lowest dose [ see Dosage and Administration (2.3), Warnings and Precautions (5.5), Clinical Pharmacology (12.2)].7.3 AmlodipineWhen sildenafil citrate 100 mg was co-administered with amlodipine (5 mg or 10 mg) to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic [ see Warnings and Precautions (5.5), Clinical Pharmacology (12.2)].7.4 Ritonavir and other CYP3A4 inhibitorsCo-administration of ritonavir, a strong CYP3A4 inhibitor, greatly increased the systemic exposure of sildenafil (11-fold increase in AUC).

In case of emergency/overdose

It is therefore recommended not to exceed a maximum single dose of 25 mg of sildenafil citrate in a 48 hour period [ see Dosage and Administration (2.4), Warnings and Precautions (5.6), Clinical Pharmacology (12.3)].Co-administration of erythromycin, a moderate CYP3A4 inhibitor, resulted in a 160% and 182% increases in sildenafil C maxand AUC, respectively.

• Side effects from high doses may include dizziness, flushing, or stomach upset.
• The onset of action is typically within 30 to 60 minutes after intake.
• Patients should avoid heavy meals before taking sildenafil for quicker results.
• Overdose symptoms include chest pain, loss of vision, and fainting.
• Sildenafil is not a cure for erectile dysfunction but enhances blood flow temporarily.
• Medical review is crucial for safety when considering high-dose sildenafil.

Co-administration of saquinavir, a strong CYP3A4 inhibitor, resulted in 140% and 210% increases in sildenafil C maxand AUC, respectively. Stronger CYP3A4 inhibitors such as ketoconazole or itraconazole could be expected to have greater effects than seen with saquinavir.

• Regular use of 120 mg sildenafil is not recommended without medical supervision.
• Potential interactions include blood pressure medications and certain antibiotics.
• Always check for contraindications before using sildenafil at high doses.
• The safety profile of large doses has not been well studied in women.
• Avoid driving or operating machinery until you know how sildenafil affects you.
• Keep track of side effects to report to your healthcare provider promptly.

A starting dose of 25 mg of sildenafil citrate should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [ see Dosage and Administration (2.4), Clinical Pharmacology (12.3)].7.5 AlcoholIn a drug-drug interaction study sildenafil 50 mg given with alcohol 0.5 g/kg in which mean maximum blood alcohol levels of 0.08% was achieved, sildenafil did not potentiate the hypotensive effect of alcohol in healthy volunteers [see Clinical Pharmacology (12.2)].

8.5 Geriatric Use

Marketing and sales

What is sildenafil used for?

Administration of sildenafil citrate with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. Consistent with its known effects on the nitric oxide/cGMP pathway, sildenafil citrate was shown to potentiate the hypotensive effects of nitrates [ see Dosage and Administration (2.3), Contraindications (4.1), Clinical Pharmacology (12.2)].

• Sildenafil citrate is primarily used to treat erectile dysfunction.
• 120 mg is a high dosing level and should only be used under medical supervision.
• The typical starting dose for sildenafil is 50 mg; 120 mg exceeds standard recommendations.
• High doses can increase the risk of side effects such as headaches and low blood pressure.
• Sildenafil works by relaxing blood vessels in the penis to facilitate an erection.
• Overdose of sildenafil citrate can cause severe hypotension and vision disturbances.

Use caution when co-administering alpha-blockers with sildenafil citrate because of potential additive blood pressure-lowering effects.

• Sildenafil 120 mg can cause flushing and nasal congestion as common side effects.
• It is important to follow medical advice to minimize health risks.
• The drug's effectiveness can be influenced by other health conditions like diabetes.
• Consuming grapefruit or grapefruit juice may affect sildenafil’s metabolism.
• Patients should seek emergency care if experiencing an erection lasting longer than 4 hours.
• Sildenafil’s effects typically last about 4-6 hours, depending on individual factors.

When sildenafil citrate is co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil citrate treatment and sildenafil citrate should be initiated at the lowest dose [ see Dosage and Administration (2.3), Warnings and Precautions (5.5), Clinical Pharmacology (12.2)]. When sildenafil citrate 100 mg was co-administered with amlodipine (5 mg or 10 mg) to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic [ see Warnings and Precautions (5.5), Clinical Pharmacology (12.2)]. Co-administration of ritonavir, a strong CYP3A4 inhibitor, greatly increased the systemic exposure of sildenafil (11-fold increase in AUC). It is therefore recommended not to exceed a maximum single dose of 25 mg of sildenafil citrate in a 48 hour period [ see Dosage and Administration (2.4), Warnings and Precautions (5.6), Clinical Pharmacology (12.3)].

Co-administration of erythromycin, a moderate CYP3A4 inhibitor, resulted in a 160% and 182% increases in sildenafil C maxand AUC, respectively. A starting dose of 25 mg of sildenafil citrate should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [ see Dosage and buy sildenafil uk Administration (2.4), Clinical Pharmacology (12.3)]. In a drug-drug interaction study sildenafil 50 mg given with alcohol 0.5 g/kg in which mean maximum blood alcohol levels of 0.08% was achieved, sildenafil did not potentiate the hypotensive effect of alcohol in healthy volunteers [see Clinical Pharmacology (12.2)].

2.1 Sildenafil Tablets

8 USE IN SPECIFIC POPULATIONS 8.1 PregnancyRisk SummarySildenafil Citrate is not indicated for use in females.There are no data with the use of Sildenafil Citrate in pregnant women to inform any drug-associated risks for adverse developmental outcomes. Animal reproduction studies conducted with sildenafil did not show adverse developmental outcomes when administered during organogenesis in rats and rabbits at oral doses up to 16 and 32 times, respectively, the maximum recommended human dose (MRHD) of 100 mg/day on a mg/m 2basis (see Data).DataAnimal DataNo evidence of teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits which received oral doses up to 200 mg/kg/day during organogenesis. These doses represent, respectively, about 16 and 32 times the MRHD on a mg/m 2basis in a 50 kg subject. In the rat pre- and postnatal development study, the no observed adverse effect dose was 30 mg/kg/day given for 36 days, about 2 times the MRHD on a mg/m 2basis in a 50 kg subject.8.4 Pediatric UseSildenafil citrate is not indicated for use in pediatric patients. Safety and effectiveness have not been established in pediatric patients.8.5 Geriatric UseHealthy elderly volunteers (65 years or over) had a reduced clearance of sildenafil resulting in approximately 84% and 107% higher plasma AUC values of sildenafil and its active N-desmethyl metabolite, respectively, compared to those seen in healthy young volunteers (18 to 45 years) [ see Clinical Pharmacology (12.3)].

Usual Pediatric Dose for:

Due to age-differences in plasma protein binding, the corresponding increase in the AUC of free (unbound) sildenafil and its active N-desmethyl metabolite were 45% and 57%, respectively [ see Clinical Pharmacology (12.3)].Of the total number of subjects in clinical studies of sildenafil citrate, 18% were 65 years and older, while 2% were 75 years and older. No overall differences in safety or efficacy were observed between older (≥ 65 years of age) and younger (< 65 years of age) subjects.However, since higher plasma levels may increase the incidence of adverse reactions, a starting dose of 25 mg should be considered in older subjects due to the higher systemic exposure [ see Dosage and Administration (2.5)].8.6 Renal ImpairmentNo dose adjustment is required for mild (CLcr=50 to 80 mL/min) and moderate (CLcr=30 to 49 mL/min) renal impairment.

Less common

8 USE IN SPECIFIC POPULATIONS 8.1 PregnancyRisk SummarySildenafil Citrate is not indicated for use in females.There are no data with the use of Sildenafil Citrate in pregnant women to inform any drug-associated risks for adverse developmental outcomes. Animal reproduction studies conducted with sildenafil did not show adverse developmental outcomes when administered during organogenesis in rats and rabbits at oral doses up to 16 and 32 times, respectively, the maximum recommended human dose (MRHD) of 100 mg/day on a mg/m 2basis (see Data).DataAnimal DataNo evidence of teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits which received oral doses up to 200 mg/kg/day during organogenesis. These doses represent, respectively, about 16 and 32 times the MRHD on a mg/m 2basis in a 50 kg subject. In the rat pre- and postnatal development study, the no observed adverse effect dose was 30 mg/kg/day given for 36 days, about 2 times the MRHD on a mg/m 2basis in a 50 kg subject.8.4 Pediatric UseSildenafil citrate is not indicated for use in pediatric patients.

7.2 Alpha-blockers

When sildenafil citrate is co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil citrate treatment and sildenafil citrate should be initiated at the lowest dose [ see Dosage and Administration (2.3), Warnings and Precautions (5.5), Clinical Pharmacology (12.2)].7.3 AmlodipineWhen sildenafil citrate 100 mg was co-administered with amlodipine (5 mg or 10 mg) to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic [ see Warnings and Precautions (5.5), Clinical Pharmacology (12.2)].7.4 Ritonavir and other CYP3A4 inhibitorsCo-administration of ritonavir, a strong CYP3A4 inhibitor, greatly increased the systemic exposure of sildenafil (11-fold increase in AUC). It is therefore recommended not to exceed a maximum single dose of 25 mg of sildenafil citrate in a 48 hour period [ see Dosage and Administration (2.4), Warnings and Precautions (5.6), Clinical Pharmacology (12.3)].Co-administration of erythromycin, a moderate CYP3A4 inhibitor, resulted in a 160% and 182% increases in sildenafil C maxand AUC, respectively. Co-administration of saquinavir, a strong CYP3A4 inhibitor, resulted in 140% and 210% increases in sildenafil C maxand AUC, respectively. Stronger CYP3A4 inhibitors such as ketoconazole or itraconazole could be expected to have greater effects than seen with saquinavir. A starting dose of 25 mg of sildenafil citrate should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [ see Dosage and Administration (2.4), Clinical Pharmacology (12.3)].7.5 AlcoholIn a drug-drug interaction study sildenafil 50 mg given with alcohol 0.5 g/kg in which mean maximum blood alcohol levels of 0.08% was achieved, sildenafil did not potentiate the hypotensive effect of alcohol in healthy volunteers [see Clinical Pharmacology (12.2)].

What are the most common side effects of sildenafil?

Administration of sildenafil citrate with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. Consistent with its known effects on the nitric oxide/cGMP pathway, sildenafil citrate was shown to potentiate the hypotensive effects of nitrates [ see Dosage and Administration (2.3), Contraindications (4.1), Clinical Pharmacology (12.2)]. Use caution when co-administering alpha-blockers with sildenafil citrate because of potential additive blood pressure-lowering effects. When sildenafil citrate is co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil citrate treatment and sildenafil citrate should be initiated at the lowest dose [ see Dosage and Administration (2.3), Warnings and Precautions (5.5), Clinical Pharmacology (12.2)]. When sildenafil citrate 100 mg was co-administered with amlodipine (5 mg or 10 mg) to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic [ see Warnings and Precautions (5.5), Clinical Pharmacology (12.2)].

Risk Summary

Co-administration of ritonavir, a strong CYP3A4 inhibitor, greatly increased the systemic exposure of sildenafil (11-fold increase in AUC). It is therefore recommended not to exceed a maximum single dose of 25 mg of sildenafil citrate in a 48 hour period [ see Dosage and Administration (2.4), Warnings and Precautions (5.6), Clinical Pharmacology (12.3)]. Co-administration of erythromycin, a moderate CYP3A4 inhibitor, resulted in a 160% and 182% increases in sildenafil C maxand AUC, respectively. A starting dose of 25 mg of sildenafil citrate should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [ see Dosage and buy sildenafil uk Administration (2.4), Clinical Pharmacology (12.3)]. In a drug-drug interaction study sildenafil 50 mg given with alcohol 0.5 g/kg in which mean maximum blood alcohol levels of 0.08% was achieved, sildenafil did not potentiate the hypotensive effect of alcohol in healthy volunteers [see Clinical Pharmacology (12.2)]. Safety and effectiveness have not been established in pediatric patients.8.5 Geriatric UseHealthy elderly volunteers (65 years or over) had a reduced clearance of sildenafil resulting in approximately 84% and 107% higher plasma AUC values of sildenafil and its active N-desmethyl metabolite, respectively, compared to those seen in healthy young volunteers (18 to 45 years) [ see Clinical Pharmacology (12.3)].

Chemical synthesis

The following adverse reactions have been identified during post approval use of sildenafil citrate. These events have been chosen for inclusion either due to their seriousness, reporting frequency, lack of clear alternative causation, or a combination of these factors. Serious cardiovascular, cerebrovascular, and vascular events, including myocardial infarction, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, transient ischemic attack, hypertension, subarachnoid and intracerebral hemorrhages, and pulmonary hemorrhage have been reported post-marketing in temporal association with the use of sildenafil citrate. It is not possible to determine whether these events are related directly to sildenafil citrate, to sexual activity, to the patient’s underlying cardiovascular disease, to a combination of these factors, or to other factors [ see Warnings and Precautions (5.1)and Patient Counseling Information (17)]. Hemic and Lymphatic:vaso-occlusive crisis: In a small, prematurely terminated study of sildenafil tablets, 20 mg (sildenafil) in patients with pulmonary arterial hypertension (PAH) secondary to sickle cell disease, vaso-occlusive crises requiring hospitalization were more commonly reported in patients who received sildenafil than in those randomized to placebo.

What’s the difference between sildenafil 50 mg and 100 mg?

The clinical relevance of this finding to men treated with sildenafil tablets, 25 mg, 50 mg and 100 mg for ED is not known. Nervous:seizure, seizure recurrence, anxiety, and transient global amnesia. Hearing:Cases of sudden decrease or loss of hearing have been reported postmarketing in temporal association with the use of PDE5 inhibitors, including sildenafil citrate. It is not possible to determine whether these reported events are related directly to the use of sildenafil citrate, to the patient’s underlying risk factors for hearing loss, a combination of these factors, or to other factors [ see Warnings and Precautions (5.4)and Patient Counseling Information (17)]. Ocular:diplopia, temporary vision loss/decreased vision, ocular redness or bloodshot appearance, ocular burning, ocular swelling/pressure, increased intraocular pressure, retinal edema, retinal vascular disease or bleeding, and vitreous traction/detachment.

What should I know about sildenafil before taking it?

Non-arteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision, has been reported rarely post-marketing in temporal association with the use of phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil citrate. Most, but not all, of these patients had underlying anatomic or vascular risk factors for developing NAION, including but not necessarily limited to: low cup to disc ratio (“crowded disc”), age over 50, diabetes, hypertension, coronary artery disease, hyperlipidemia and smoking [ see Warnings and Precautions (5.3)and Patient Counseling Information (17)]. Urogenital:prolonged erection, priapism [ see Warnings and Precautions (5.2)and Patient Counseling Information (17)], and hematuria. 7 DRUG INTERACTIONS 7.1 NitratesAdministration of sildenafil citrate with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. Consistent with its known effects on the nitric oxide/cGMP pathway, sildenafil citrate was shown to potentiate the hypotensive effects of nitrates [ see Dosage and Administration (2.3), Contraindications (4.1), sildenafil oral jelly 100 mg Clinical Pharmacology (12.2)].7.2 Alpha-blockersUse caution when co-administering alpha-blockers with sildenafil citrate because of potential additive blood pressure-lowering effects. Due to age-differences in plasma protein binding, the corresponding increase in the AUC of free (unbound) sildenafil and its active N-desmethyl metabolite were 45% and 57%, respectively [ see Clinical Pharmacology (12.3)].Of the total number of subjects in clinical studies of sildenafil citrate, 18% were 65 years and older, while 2% were 75 years and older. No overall differences in safety or efficacy were observed between older (≥ 65 years of age) and younger (< 65 years of age) subjects.However, since higher plasma levels may increase the incidence of adverse reactions, a starting dose of 25 mg should be considered in older subjects due to the higher systemic exposure [ see Dosage and Administration (2.5)].8.6 Renal ImpairmentNo dose adjustment is required for mild (CLcr=50 to 80 mL/min) and moderate (CLcr=30 to 49 mL/min) renal impairment.