5 WARNINGS AND PRECAUTIONS

Based on published literature, the annual incidence of NAION is 2.5-11.8 cases per 100,000 in males aged ≥ 50. An observational case-crossover study evaluated the risk of NAION when PDE5 inhibitor use, as a class, occurred immediately before NAION onset (within 5 half-lives), compared to PDE5 inhibitor use in a prior time period. The results suggest an approximate 2-fold increase in the risk of NAION, with a risk estimate of 2.15 (95% CI 1.06, 4.34). A similar study reported a consistent result, with a risk estimate of 2.27 (95% CI 0.99, 5.20).

• At 200mg, visual side effects like blue-green tint are more pronounced.
• This occurs because PDE6 in retinal rods is also inhibited at high doses.
• Transient light sensitivity and blurred vision may last several hours.
• Risk increases with dose; 200mg has higher incidence than 50mg or 100mg.
• In most cases, visual changes are reversible upon drug elimination.
• Patients with retinitis pigmentosa should avoid sildenafil altogether.
• NAION (non-arteritic ischemic optic neuropathy) risk is dose-independent.
• Annual eye exams may be advised for patients using high-dose sildenafil.
• Report any sudden vision loss immediately; it may be permanent.

Other risk factors for NAION, such as the presence of “crowded” optic disc, may have contributed to the occurrence of NAION in these studies.Neither the rare post-marketing reports, nor the association of PDE5 inhibitor use and NAION in the observational studies, substantiate a causal relationship between PDE5 inhibitor use and NAION [see Adverse Reactions (6.2)].Physicians should consider whether their patients with underlying NAION risk factors could be adversely affected by use of PDE5 inhibitors. Individuals who have already experienced NAION are at increased risk of NAION recurrence.

• Sildenafil 200mg can lower blood pressure; use caution if on antihypertensives.
• Patients with coronary artery disease should avoid strenuous sex after high dose.
• A cardiac stress test may be recommended before prescribing 200mg.
• Congestive heart failure patients are at higher risk of adverse cardiac events.
• Aortic stenosis patients may experience syncope with vasodilation from 200mg.
• Left ventricular outflow obstruction increases risk of hypotensive reactions.
• Beta blockers or calcium channel blockers can amplify blood pressure drop.
• Patients with uncontrolled arrhythmias should not take 200mg sildenafil.
• Discuss any history of heart attack, stroke, or chest pain with your doctor.

Therefore, PDE5 inhibitors, including sildenafil tablets, should be used with caution in these patients and only when the anticipated benefits outweigh the risks. Individuals with “crowded” optic disc are also considered at greater risk for NAION compared to the general population, however, evidence is insufficient to support screening of prospective users of PDE5 inhibitors, including sildenafil tablets, for this uncommon condition.There are no controlled clinical data on the safety or efficacy of sildenafil tablets in patients with retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases); if prescribed, this should be done with caution.5.4 Hearing LossPhysicians should advise patients to stop taking PDE5 inhibitors, including sildenafil tablets, and seek prompt medical attention in the event of sudden decrease or loss of hearing. These events, which may be accompanied by tinnitus and dizziness, have been reported in temporal association to the intake of PDE5 inhibitors, including sildenafil tablets.

8.4 Pediatric Use

It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors [see Adverse Reactions (6.1, 6.2)].5.5 Hypotension when Co-administered with Alpha-blockers or Anti-hypertensivesAlpha-blockersCaution is advised when PDE5 inhibitors are co-administered with alpha-blockers. PDE5 inhibitors, including sildenafil citrate, and alpha-adrenergic blocking agents are both vasodilators with blood pressure lowering effects. When vasodilators are used in combination, an additive effect on blood pressure may occur.

• Overdose of 200mg sildenafil can cause severe hypotension and priapism.
• Taking multiple 200mg tablets (e.g., 400mg) greatly increases danger.
• Symptoms: prolonged erection, chest pain, nausea, dizziness, fainting.
• Emergency treatment includes supportive care and possibly vasopressors.
• Priapism lasting >4 hours may require intracavernosal aspiration or surgery.
• Activated charcoal may be given if ingestion is recent.
• No specific antidote for sildenafil overdose exists.
• Dialysis is ineffective due to high protein binding of the drug.
• Always call poison control or go to ER if overdose is suspected.

In some patients, concomitant use of these two drug classes can lower blood pressure significantly [see Drug Interactions (7.2) and Clinical Pharmacology (12.2)] leading to symptomatic hypotension (e.g., dizziness, lightheadedness, fainting).Consideration should be given to the following:Patients who demonstrate hemodynamic instability on alpha-blocker therapy alone are at increased risk of symptomatic hypotension with concomitant use of PDE5 inhibitors.

Patients should be stable on alpha-blocker therapy prior to initiating a PDE5 inhibitor.In those patients who are stable on alpha-blocker therapy, PDE5 inhibitors should be initiated at the lowest dose [see Dosage and Administration (2.3)].In those patients already taking an optimized dose of a PDE5 inhibitor, alpha-blocker therapy should be initiated at the lowest dose. Stepwise increase in alpha-blocker dose may be associated with further lowering of blood pressure when taking a PDE5 inhibitor.Safety of combined use of PDE5 inhibitors and alpha-blockers may be affected by other variables, including intravascular volume depletion and other anti-hypertensive drugs.Anti-hypertensivesSildenafil citrate has systemic vasodilatory properties and may further lower blood pressure in patients taking anti-hypertensive medications.In a separate drug interaction study, when amlodipine, 5 mg or 10 mg, and sildenafil tablets, 100 mg were orally administered concomitantly to hypertensive patients mean additional blood pressure reduction of 8 mmHg systolic and 7 mmHg diastolic were noted [see Drug Interactions (7.3) and Clinical Pharmacology (12.2)].5.6 Adverse Reactions with the Concomitant Use of RitonavirThe concomitant administration of the protease inhibitor ritonavir substantially increases serum concentrations of sildenafil (11-fold increase in AUC). If sildenafil tablets are prescribed to patients taking ritonavir, caution should be used. Data from subjects exposed to high systemic levels of sildenafil sildenafil citrate tablets 50 mg are limited. Decreased blood pressure, syncope, and prolonged erection were reported in some healthy volunteers exposed to high doses of sildenafil (200-800 mg). To decrease the chance of adverse reactions in patients taking ritonavir, a decrease in sildenafil dosage is recommended [see Dosage and Administration (2.4), Drug Interactions (7.4), and Clinical Pharmacology (12.3)].5.7 Combination with other PDE5 Inhibitors or Other Erectile Dysfunction TherapiesThe safety and efficacy of combinations of sildenafil tablets with other PDE5 Inhibitors, including REVATIO or other pulmonary arterial hypertension (PAH) treatments containing sildenafil, or other treatments for erectile dysfunction have not been studied. Such combinations may further lower blood pressure. Therefore, the use of such combinations is not recommended.5.8 Effects on BleedingThere have been postmarketing reports of bleeding events in patients who have taken sildenafil tablets. A causal relationship between sildenafil tablets and these events has not been established. In humans, sildenafil tablets have no effect on bleeding time when taken alone or with aspirin.

However, in vitro studies with human platelets indicate that sildenafil potentiates the antiaggregatory effect of sodium nitroprusside (a nitric oxide donor).

• Sildenafil citrate may interact with certain antifungals and antibiotics, increasing side effects.
• Always review current medications with your healthcare provider before using sildenafil citrate.
• Report any adverse reactions immediately to prevent worsening health conditions.

In addition, the combination of heparin and sildenafil tablets had an additive effect on bleeding time in the anesthetized rabbit, but this interaction has not been studied in humans.The safety of sildenafil citrate is unknown in patients with bleeding disorders and patients with active peptic ulceration.5.9 Counseling Patients About Sexually Transmitted DiseasesThe use of sildenafil tablets offers no protection against sexually transmitted diseases. Counseling of patients about the protective measures necessary to guard against sexually transmitted diseases, including the Human Immunodeficiency Virus (HIV), may be considered. There is a potential for cardiac risk of sexual activity in patients with preexisting cardiovascular disease. The evaluation of erectile dysfunction should include a determination of potential underlying causes and the identification of appropriate treatment following a complete medical assessment. Sildenafil citrate has systemic vasodilatory properties that resulted in transient decreases in supine blood pressure in healthy volunteers (mean maximum decrease of 8.4/5.5 mmHg), [see Clinical Pharmacology (12.2)].

Before taking this medicine

Based on published literature, the annual incidence of NAION is 2.5-11.8 cases per 100,000 in males aged ≥ 50. An observational case-crossover study evaluated the risk of NAION when PDE5 inhibitor use, as a class, occurred immediately before NAION onset (within 5 half-lives), compared to PDE5 inhibitor use in a prior time period. The results suggest an approximate 2-fold increase in the risk of NAION, with a risk estimate of 2.15 (95% CI 1.06, 4.34). A similar study reported a consistent result, with a risk estimate of 2.27 (95% CI 0.99, 5.20). Other risk factors for NAION, such as the presence of “crowded” optic disc, may have contributed to the occurrence of NAION in these studies.Neither the rare post-marketing reports, nor the association of PDE5 inhibitor use and NAION in the observational studies, substantiate a causal relationship between PDE5 inhibitor use and NAION [see Adverse Reactions (6.2)].Physicians should consider whether their patients with underlying NAION risk factors could be adversely affected by use of PDE5 inhibitors.

What is sildenafil used for?

Individuals who have already experienced NAION are at increased risk of NAION recurrence. Therefore, PDE5 inhibitors, including sildenafil tablets, should be used with caution in these patients and only when the anticipated benefits outweigh the risks. Individuals with “crowded” optic disc are also considered at greater risk for NAION compared to the general population, however, evidence is insufficient to support screening of prospective users of PDE5 inhibitors, including sildenafil tablets, for this uncommon condition.There are no controlled clinical data on the safety or efficacy of sildenafil tablets in patients with retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases); if prescribed, this should be done with caution.5.4 Hearing LossPhysicians should advise patients to stop taking PDE5 inhibitors, including sildenafil tablets, and seek prompt medical attention in the event of sudden decrease or loss of hearing. These events, which may be accompanied by tinnitus and dizziness, have been reported in temporal association to the intake of PDE5 inhibitors, including sildenafil tablets. It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors [see Adverse Reactions (6.1, 6.2)].5.5 Hypotension when Co-administered with Alpha-blockers or Anti-hypertensivesAlpha-blockersCaution is advised when PDE5 inhibitors are co-administered with alpha-blockers.

Professional resources

PDE5 inhibitors, including sildenafil citrate, and alpha-adrenergic blocking agents are both vasodilators with blood pressure lowering effects. When vasodilators are used in combination, an additive effect on blood pressure may occur. In some patients, concomitant use of these two drug classes can lower blood pressure significantly [see Drug Interactions (7.2) and Clinical Pharmacology (12.2)] leading to symptomatic hypotension (e.g., dizziness, lightheadedness, fainting).Consideration should be given to the following:Patients who demonstrate hemodynamic instability on alpha-blocker therapy alone are at increased risk of symptomatic hypotension with concomitant use of PDE5 inhibitors. Patients should be stable on alpha-blocker therapy prior to initiating a PDE5 inhibitor.In those patients who are stable on alpha-blocker therapy, PDE5 inhibitors should be initiated at the lowest dose [see Dosage and Administration (2.3)].In those patients already taking an optimized dose of a PDE5 inhibitor, alpha-blocker therapy should be initiated at the lowest dose. Stepwise increase in alpha-blocker dose may be associated with further lowering of blood pressure when taking a PDE5 inhibitor.Safety of combined use of PDE5 inhibitors and alpha-blockers may be affected by other variables, including intravascular volume depletion and other anti-hypertensive drugs.Anti-hypertensivesSildenafil citrate has systemic vasodilatory properties and may further lower blood pressure in patients taking anti-hypertensive medications.In a separate drug interaction study, when amlodipine, 5 mg or 10 mg, and sildenafil tablets, 100 mg were orally administered concomitantly to hypertensive patients mean additional blood pressure reduction of 8 mmHg systolic and 7 mmHg diastolic were noted [see Drug Interactions (7.3) and Clinical Pharmacology (12.2)].5.6 Adverse Reactions with the Concomitant Use of RitonavirThe concomitant administration of the protease inhibitor ritonavir substantially increases serum concentrations of sildenafil (11-fold increase in AUC). While this normally would be expected to be of little consequence in most patients, prior to prescribing sildenafil tablets, physicians should carefully consider whether their patients with underlying cardiovascular disease could be affected adversely by such vasodilatory effects, especially in combination with sexual activity. Use with caution in patients with the following underlying conditions which can be particularly sensitive to the actions of vasodilators including sildenafil citrate - those with left ventricular outflow obstruction (e.g., aortic stenosis, idiopathic hypertrophic subaortic stenosis) and those with severely impaired autonomic control of blood pressure. There are no controlled clinical data on the safety or efficacy of sildenafil tablets in the following groups; if prescribed, this should be done with caution.

What happens if I miss a dose?

If sildenafil tablets are prescribed to patients taking ritonavir, caution should be used. Data from subjects exposed to high systemic levels of sildenafil sildenafil citrate tablets 50 mg are limited. Decreased blood pressure, syncope, and prolonged erection were reported in some healthy volunteers exposed to high doses of sildenafil (200-800 mg). To decrease the chance of adverse reactions in patients taking ritonavir, a decrease in sildenafil dosage is recommended [see Dosage and Administration (2.4), Drug Interactions (7.4), and Clinical Pharmacology (12.3)].5.7 Combination with other PDE5 Inhibitors or Other Erectile Dysfunction TherapiesThe safety and efficacy of combinations of sildenafil tablets with other PDE5 Inhibitors, including REVATIO or other pulmonary arterial hypertension (PAH) treatments containing sildenafil, or other treatments for erectile dysfunction have not been studied. Such combinations may further lower blood pressure.

How is sildenafil supplied (dosage forms)?

Therefore, the use of such combinations is not recommended.5.8 Effects on BleedingThere have been postmarketing reports of bleeding events in patients who have taken sildenafil tablets. A causal relationship between sildenafil tablets and these events has not been established. In humans, sildenafil tablets have no effect on bleeding time when taken alone or with aspirin. However, in vitro studies with human platelets indicate that sildenafil potentiates the antiaggregatory effect of sodium nitroprusside (a nitric oxide donor). In addition, the combination of heparin and sildenafil tablets had an additive effect on bleeding time in the anesthetized rabbit, but this interaction has not been studied in humans.The safety of sildenafil citrate is unknown in patients with bleeding disorders and patients with active peptic ulceration.5.9 Counseling Patients About Sexually Transmitted DiseasesThe use of sildenafil tablets offers no protection against sexually transmitted diseases.

Drug Interactions

Counseling of patients about the protective measures necessary to guard against sexually transmitted diseases, including the Human Immunodeficiency Virus (HIV), may be considered. There is a potential for cardiac risk of sexual activity in patients with preexisting cardiovascular disease. The evaluation of erectile dysfunction should include a determination of potential underlying causes and the identification of appropriate treatment following a complete medical assessment. Sildenafil citrate has systemic vasodilatory properties that resulted in transient decreases in supine blood pressure in healthy volunteers (mean maximum decrease of 8.4/5.5 mmHg), [see Clinical Pharmacology (12.2)]. While this normally would be expected to be of little consequence in most patients, prior to prescribing sildenafil tablets, physicians should carefully consider whether their patients with underlying cardiovascular disease could be affected adversely by such vasodilatory effects, especially in combination with sexual activity. • Patients who have suffered a myocardial infarction, stroke, or life-threatening arrhythmia within the last 6 months; • Patients with resting hypotension (BP <90/50 mmHg) or hypertension (BP >170/110 mmHg); • Patients with cardiac failure or coronary artery disease causing sildenafil for women unstable angina.

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What should I do if I miss a dose of sildenafil?

CAUTION & WARNING:

Prolonged erection greater than 4 hours and priapism (painful erections greater than 6 hours in duration) have been reported infrequently since market approval of sildenafil tablets. If priapism is not treated immediately, penile tissue damage and permanent loss of potency could result. Sildenafil tablets should be used with caution in patients with anatomical deformation of the penis (such as angulation, cavernosal fibrosis or Peyronie’s disease), or in patients who have conditions which may predispose them to priapism (such as sickle cell anemia, multiple myeloma, or leukemia). However, there are no controlled clinical data on the safety or efficacy of sildenafil tablets in patients with sickle cell or related anemias. Physicians should advise patients to stop use of all phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil tablets, and seek medical attention in the event of a sudden loss of vision in one or both eyes. Other risk factors for NAION, such as the presence of “crowded” optic disc, may have contributed to the occurrence of NAION in these studies. Physicians should consider whether their patients with underlying NAION risk factors could be adversely affected by use of PDE5 inhibitors.

2.2 Use with Food

Use with caution in patients with the following underlying conditions which can be particularly sensitive to the actions of vasodilators including sildenafil citrate - those with left ventricular outflow obstruction (e.g., aortic stenosis, idiopathic hypertrophic subaortic stenosis) and those with severely impaired autonomic control of blood pressure. There are no controlled clinical data on the safety or efficacy of sildenafil tablets in the following groups; if prescribed, this should be done with caution. • Patients who have suffered a myocardial infarction, stroke, or life-threatening arrhythmia within the last 6 months; • Patients with resting hypotension (BP <90/50 mmHg) or hypertension (BP >170/110 mmHg); • Patients with cardiac failure or coronary artery disease causing sildenafil for women unstable angina. Prolonged erection greater than 4 hours and priapism (painful erections greater than 6 hours in duration) have been reported infrequently since market approval of sildenafil tablets. If priapism is not treated immediately, penile tissue damage and permanent loss of potency could result.

How does sildenafil work (mechanism of action)?

Sildenafil tablets should be used with caution in patients with anatomical deformation of the penis (such as angulation, cavernosal fibrosis or Peyronie’s disease), or in patients who have conditions which may predispose them to priapism (such as sickle cell anemia, multiple myeloma, or leukemia). However, there are no controlled clinical data on the safety or efficacy of sildenafil tablets in patients with sickle cell or related anemias. Physicians should advise patients to stop use of all phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil tablets, and seek medical attention in the event of a sudden loss of vision in one or both eyes. Other risk factors for NAION, such as the presence of “crowded” optic disc, may have contributed to the occurrence of NAION in these studies. Physicians should consider whether their patients with underlying NAION risk factors could be adversely affected by use of PDE5 inhibitors.

Other variants of Cenforce that are available

Individuals with “crowded” optic disc are also considered at greater risk for NAION compared to the general population, however, evidence is insufficient to support screening of prospective users of PDE5 inhibitors, including sildenafil tablets, for this uncommon condition. There are no controlled clinical data on the safety or efficacy of sildenafil tablets in patients with retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases); if prescribed, this should be done with caution. Individuals with “crowded” optic disc are also considered at greater risk for NAION compared to the general population, however, evidence is insufficient to support screening of prospective users of PDE5 inhibitors, including sildenafil tablets, for this uncommon condition. There are no controlled clinical data on the safety or efficacy of sildenafil tablets in patients with retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases); if prescribed, this should be done with caution.