Sildenafil Citrate

SILDENAFIL CITRATE- sildenafil citrate tablet, film coated
medsource pharmaceuticals

1 INDICATIONS AND USAGE

Sildenafil tablets are indicated for the treatment of erectile dysfunction.

2 DOSAGE AND ADMINISTRATION

2.1 Dosage Information

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. The maximum recommended dosing frequency is once per day.

Based on effectiveness and toleration, the dose may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg.

2.2 Use with Food

Sildenafil tablets may be taken with or without food.

2.3 Dosage Adjustments in Specific Situations

Sildenafil tablets was 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 citrate treatment and sildenafil citrate should be initiated at 25 mg [see Warnings and Precautions (5.5), Drug Interactions (7.2), and Clinical Pharmacology (12.2)].

2.4 Dosage Adjustments Due to Drug Interactions

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) ].

2.5 Dosage Adjustments in Special Populations

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) ] .

3 DOSAGE FORMS AND STRENGTHS

Sildenafil tablets USP are supplied as blue, round, biconvex, film-coated tablets containing sildenafil citrate equivalent to 25 mg, 50 mg or 100 mg of sildenafil. Tablets are debossed with 86, 87 and 88 respectively for 25 mg, 50 mg and 100 mg strength on one side and plain on other side.

4 CONTRAINDICATIONS

4.1 Nitrates

Consistent with its known effects on the nitric oxide/cGMP pathway [ see Clinical Pharmacology (12.1, 12.2) ], sildenafil citrate was 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 citrate, 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) ].

4.2 Hypersensitivity Reactions

Sildenafil tablets is contraindicated in patients with a known hypersensitivity to sildenafil, as contained in sildenafil tablets, 25 mg, 50 mg and 100 mg and sildenafil tablets, 20 mg, or any component of the tablet. Hypersensitivity reactions have been reported, including rash and urticaria [ see Adverse Reactions (6.1) ] .

4.3 Concomitant Guanylate Cyclase (GC) Stimulators

Do not use sildenafil tablets in patients who are using a GC stimulator, such as riociguat. PDE5 inhibitors, including sildenafil citrate, may potentiate the hypotensive effects of GC stimulators.

5 WARNINGS AND PRECAUTIONS

5.1 Cardiovascular

There is a potential for cardiac risk of sexual activity in patients with preexisting cardiovascular disease. Therefore, treatments for erectile dysfunction, including sildenafil citrate, should not be generally used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status. 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 citrate, 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 citrate 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.

5.2 Prolonged Erection and Priapism

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. In the event of an erection that persists longer than 4 hours, the patient should seek immediate medical assistance. If priapism is not treated immediately, penile tissue damage and permanent loss of potency could result.

Sildenafil citrate 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 citrate in patients with sickle cell or related anemias.

5.3 Effects on the Eye

Physicians should advise patients to stop use of all phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil citrate, and seek medical attention in the event of a sudden loss of vision in one or both eyes. Such an event may be a sign of 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 association with the use 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 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. Individuals who have already experienced NAION are at increased risk of NAION recurrence. Therefore, PDE5 inhibitors, including sildenafil citrate, 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 citrate, for this uncommon condition.

There are no controlled clinical data on the safety or efficacy of sildenafil citrate in patients with retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases); if prescribed, this should be done with caution.

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