DOSAGE AND ADMINISTRATION

For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity. Sildenafil tablets were shown to potentiate the hypotensive effects of nitrates and its administration in patients who use nitric oxide donors such as organic nitrates or organic nitrites in any form is therefore contraindicated [see Contraindications (4.1),Drug Interactions (7.1),and Clinical Pharmacology (12.2)].

When sildenafil tablets are co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil tablets treatment and sildenafil tablets should be initiated at 25 mg [see Warnings and Precautions (5.5),Drug Interactions (7.2),and Clinical Pharmacology (12.2)]. Ritonavir The recommended dose for ritonavir-treated patients is 25 mg prior to sexual activity and the recommended maximum dose is 25 mg within a 48 hour period because concomitant administration increased the blood levels of sildenafil by 11-fold [see Warnings and Precautions (5.6),Drug Interactions (7.4),and Clinical Pharmacology (12.3)]. CYP3A4 Inhibitors Consider a starting dose of 25 mg in patients treated with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, or saquinavir) or erythromycin. Clinical data have shown that co-administration with saquinavir or erythromycin increased plasma levels of sildenafil by about 3 fold [see Drug Interactions (7.4)and Clinical Pharmacology (12.3)].

5.2 Worsening Pulmonary Vascular Occlusive Disease

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. Physicians 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. Alpha-blockers Caution is advised when PDE5 inhibitors are co-administered with alpha-blockers.

Who should not take sildenafil?

PDE5 inhibitors, including sildenafil tablets, and alpha-adrenergic blocking agents are both vasodilators with blood pressure lowering effects. 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. •In those patients already taking an optimized dose of a PDE5 inhibitor, alpha-blocker therapy should be initiated at the lowest dose. •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.

Are you a licensed Prescriber?

Anti-hypertensives Sildenafil tablets have 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)]. If sildenafil tablets are prescribed to patients taking ritonavir, caution should be used. Decreased blood pressure, syncope, and prolonged erection were reported in some healthy volunteers exposed to high doses of sildenafil (200 to 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)]. Consider a starting dose of 25 mg in patients > 65 years, patients with hepatic impairment (e.g., cirrhosis), and patients with severe renal impairment (creatinine clearance <30 mL/minute) because administration of sildenafil tablets in these patients resulted in higher plasma levels of sildenafil [see Use in Specific Populations ( 8.5, 8.6, 8.7)and Clinical Pharmacology ( 12.3)]. Sildenafil Tablets USP, 25 mg are white colored, round-shaped, biconvex, film coated tablets debossed with 'E' on one side and '113' on the other side. Sildenafil Tablets USP, 50 mg are white colored, round-shaped, biconvex, film coated tablets debossed with 'E' on one side and '114' on the other side. Sildenafil Tablets USP, 100 mg are white colored, round-shaped, biconvex, film coated tablets debossed with 'E' on one side and '115' on the other side. Consistent with its known effects on the nitric oxide/cGMP pathway [see Clinical Pharmacology ( 12.1, 12.2)] ,sildenafil tablets were shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated. After patients have taken sildenafil tablets, it is unknown when nitrates, if necessary, can be safely administered.

Although plasma levels of sildenafil at 24 hours post dose are much lower than at peak concentration, it is unknown whether nitrates can be safely co-administered at this time point [see Dosage and Administration (2.3),Drug Interactions (7.1),and Clinical Pharmacology (12.2)]. Sildenafil tablets are contraindicated in patients sildenafil citrate tablets 50 mg with a known hypersensitivity to sildenafil, as contained in sildenafil tablets and REVATIO, or any component of the tablet. Therefore, treatments for erectile dysfunction, including sildenafil tablets, should not be generally used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status. Sildenafil tablets have 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.

• Sildenafil was originally developed to treat hypertension and angina.
• Its effect lasts approximately 4-6 hours depending on individual factors.
• Side effects may include muscle aches and skin rash in some cases.
• Discuss all medications with your doctor to avoid harmful interactions.
• Do not take sildenafil with fatty foods to ensure quicker action.

Use with caution in patients with the following underlying conditions which can be particularly sensitive to the actions of vasodilators including sildenafil tablets – 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 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.

What Are Warnings and Precautions for Sildenafil?

For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity. Sildenafil tablets were shown to potentiate the hypotensive effects of nitrates and its administration in patients who use nitric oxide donors such as organic nitrates or organic nitrites in any form is therefore contraindicated [see Contraindications (4.1),Drug Interactions (7.1),and Clinical Pharmacology (12.2)]. When sildenafil tablets are co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil tablets treatment and sildenafil tablets should be initiated at 25 mg [see Warnings and Precautions (5.5),Drug Interactions (7.2),and Clinical Pharmacology (12.2)]. Ritonavir The recommended dose for ritonavir-treated patients is 25 mg prior to sexual activity and the recommended maximum dose is 25 mg within a 48 hour period because concomitant administration increased the blood levels of sildenafil by 11-fold [see Warnings and Precautions (5.6),Drug Interactions (7.4),and Clinical Pharmacology (12.3)].

What should I know about sildenafil before taking it?

CYP3A4 Inhibitors Consider a starting dose of 25 mg in patients treated with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, or saquinavir) or erythromycin. Clinical data have shown that co-administration with saquinavir or erythromycin increased plasma levels of sildenafil by about 3 fold [see Drug Interactions (7.4)and Clinical Pharmacology (12.3)]. Consider a starting dose of 25 mg in patients > 65 years, patients with hepatic impairment (e.g., cirrhosis), and patients with severe renal impairment (creatinine clearance <30 mL/minute) because administration of sildenafil tablets in these patients resulted in higher plasma levels of sildenafil [see Use in Specific Populations ( 8.5, 8.6, 8.7)and Clinical Pharmacology ( 12.3)]. Sildenafil Tablets USP, 25 mg are white colored, round-shaped, biconvex, film coated tablets debossed with 'E' on one side and '113' on the other side. Sildenafil Tablets USP, 50 mg are white colored, round-shaped, biconvex, film coated tablets debossed with 'E' on one side and '114' on the other side.

Is 20 mg of sildenafil effective for ED?

Sildenafil Tablets USP, 100 mg are white colored, round-shaped, biconvex, film coated tablets debossed with 'E' on one side and '115' on the other side. Consistent with its known effects on the nitric oxide/cGMP pathway [see Clinical Pharmacology ( 12.1, 12.2)] ,sildenafil tablets were shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated. After patients have taken sildenafil tablets, it is unknown when nitrates, if necessary, can be safely administered. Although plasma levels of sildenafil at 24 hours post dose are much lower than at peak concentration, it is unknown whether nitrates can be safely co-administered at this time point [see Dosage and Administration (2.3),Drug Interactions (7.1),and Clinical Pharmacology (12.2)]. Sildenafil tablets are contraindicated in patients sildenafil citrate tablets 50 mg with a known hypersensitivity to sildenafil, as contained in sildenafil tablets and REVATIO, or any component of the tablet. 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).

How should I take sildenafil?

However, there are no controlled clinical data on the safety or efficacy of sildenafil tablets in patients with sickle cell or related anemias.

17. Patient Counseling Information

The 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. 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. Such an event may be a signof non-arteritic anterior ischemic optic neuropathy (NAION), a rare condition and a cause of decreased vision including permanent loss of vision, that has been reported rarely post-marketing in temporal associationwith theuse of all PDE5 inhibitors. Based on published literature, the annual incidence of NAION is 2.5 to 11.8 cases per 100,000 in males aged ≥ 50.An observationalcase-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. Theresults suggestan approximate 2-fold increase in the risk of NAION, with a risk estimate of 2.15 (95% CI 1.06, 4.34).

Other risk factors for NAION,such as the presence sildenafil citrate tables 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 theobservationalstudies, substantiate a causal relationship between PDE5 inhibitor use and NAION [see Adverse Reactions(6.2)]. Therefore, PDE5 inhibitors, including sildenafil tablets, should be used with caution in these patients and only when the anticipated benefits outweigh the risks.

Other uses for this medicine

Therefore, treatments for erectile dysfunction, including sildenafil tablets, should not be generally used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status. Sildenafil tablets have 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. Use with caution in patients with the following underlying conditions which can be particularly sensitive to the actions of vasodilators including sildenafil tablets – 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 unstable angina.

Warnings for other groups

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. 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. Such an event may be a signof non-arteritic anterior ischemic optic neuropathy (NAION), a rare condition and a cause of decreased vision including permanent loss of vision, that has been reported rarely post-marketing in temporal associationwith theuse of all PDE5 inhibitors.

Warnings and Precautions

Based on published literature, the annual incidence of NAION is 2.5 to 11.8 cases per 100,000 in males aged ≥ 50.An observationalcase-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. Theresults suggestan approximate 2-fold increase in the risk of NAION, with a risk estimate of 2.15 (95% CI 1.06, 4.34). Other risk factors for NAION,such as the presence sildenafil citrate tables 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 theobservationalstudies, substantiate a causal relationship between PDE5 inhibitor use and NAION [see Adverse Reactions(6.2)]. 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.

• Comparing 20mg sildenafil to other PDE5 inhibitors highlights differences.
• Tadalafil (Cialis) has a longer duration of action (up to 36 hours).
• Vardenafil (Levitra) has a similar duration to sildenafil but may be less affected by food.
• Avanafil (Stendra) has a faster onset of action (15-30 minutes).
• The choice of drug depends on individual patient needs and response.
• Tadalafil is also approved for daily use at a lower dose (2.5mg, 5mg).
• Side effect profiles are similar but can vary in frequency between individuals.
• Cost and insurance coverage often play a significant role in the choice.
• Some patients may respond better to one medication over another.
• A doctor can help determine the most appropriate medication and dose.
• It may take trial and error to find the optimal treatment.

Physicians 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.

• 20mg sildenafil provides a balance between effectiveness and safety.
• It is not a cure for ED but helps achieve and maintain an erection.
• Using sildenafil without medical advice can be risky.
• The medication may cause nasal congestion or stomach upset.
• Always follow the dosage instructions provided by your healthcare provider.

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. Alpha-blockers Caution is advised when PDE5 inhibitors are co-administered with alpha-blockers. PDE5 inhibitors, including sildenafil tablets, and alpha-adrenergic blocking agents are both vasodilators with blood pressure lowering effects. 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).

• Regulatory status of sildenafil varies by country but generally requires a prescription.
• In the UK, it is a Prescription Only Medicine (POM) but can be prescribed by pharmacists.
• In some countries, it may be available in limited quantities without a prescription.
• The FDA requires a Risk Evaluation and Mitigation Strategy (REMS) for Revatio.
• The REMS is designed to inform healthcare providers about the serious risks.
• This includes the risk of use with nitrates and the potential for hearing loss.
• The medication is subject to controlled substance regulations in some regions.
• Traveling with prescription medication requires carrying it in original packaging.
• It is advisable to have a copy of the prescription or a doctor's note when traveling.
• Laws regarding the importation of prescription drugs are strict and vary.
• Always check the legal status of the medication in your destination country.

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. •In those patients already taking an optimized dose of a PDE5 inhibitor, alpha-blocker therapy should be initiated at the lowest dose. •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-hypertensives Sildenafil tablets have 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)]. If sildenafil tablets are prescribed to patients taking ritonavir, caution should be used. Decreased blood pressure, syncope, and prolonged erection were reported in some healthy volunteers exposed to high doses of sildenafil (200 to 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)]. The 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.