Sildenafil

SILDENAFIL- sildenafil citrate powder, for suspension
Taro Pharmaceuticals U.S.A. Inc.

1 INDICATIONS AND USAGE

Sildenafil for Oral Suspension is indicated for the treatment of pulmonary arterial hypertension (WHO Group I) in adults to improve exercise ability and delay clinical worsening. The delay in clinical worsening was demonstrated when Sildenafil for Oral Suspension was added to background epoprostenol therapy [see Clinical Studies (14)].

Studies establishing effectiveness were short-term (12 to 16 weeks), and included predominately patients with New York Heart Association (NYHA) Functional Class II–III symptoms and idiopathic etiology (71%) or associated with connective tissue disease (CTD) (25%).

Limitation of Use: Adding sildenafil to bosentan therapy does not result in any beneficial effect on exercise capacity [see Clinical Studies (14)].

2 DOSAGE AND ADMINISTRATION

2.1 Sildenafil for Oral Suspension

The recommended dose of Sildenafil for Oral Suspension is 5 mg or 20 mg three times a day. Administer Sildenafil for Oral Suspension doses 4 to 6 hours apart.

In the clinical trial no greater efficacy was achieved with the use of higher doses. Treatment with doses higher than 20 mg three times a day is not recommended.

2.3 Reconstitution of the Powder for Oral Suspension

Note: Reconstitute the contents of the bottle with a total volume of 90 mL (60 mL followed by 30 mL). Refer to the detailed instructions below.

1. Tap the bottle to release the powder.
2. Remove the cap.
3. Accurately measure out 60 mL of water and pour the water into the bottle. (Figure 1)
   

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4. Replace the cap and shake the bottle vigorously for a minimum of 30 seconds. (Figure 2)
   

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5. Remove the cap.
6. Accurately measure out another 30 mL of water and add this to the bottle. You should always add a total of 90 mL of water irrespective of the dose prescribed. (Figure 3)
   

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7. Replace the cap and shake the bottle vigorously for a minimum of 30 seconds. (Figure 4)
   

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8. Remove the cap.
9. Press the bottle adaptor into the neck of the bottle (as shown on Figure 5, below). The adaptor is provided so that you can fill the oral syringe with medicine from the bottle. Replace the cap on the bottle.
   

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10. Write the expiration date of the reconstituted oral suspension on the bottle label (the expiration date of the reconstituted oral suspension is 60 days from the date of reconstitution).

Incompatibilities

Do not mix with any other medication or additional flavoring agent.

3 DOSAGE FORMS AND STRENGTHS

Sildenafil for Oral Suspension

White to off-white powders containing 1.57 g of sildenafil citrate (equivalent to 1.12 g of sildenafil) in a bottle intended for reconstitution. Following reconstitution with 90 mL of water, the volume of the oral suspension is 112 mL and the oral suspension contains 10 mg/mL sildenafil. A 2 mL oral syringe (with 0.5 mL and 2 mL dose markings) and a press-in bottle adaptor are also provided.

4 CONTRAINDICATIONS

Sildenafil for Oral Suspension is contraindicated in patients with:

• Concomitant use of organic nitrates in any form, either regularly or intermittently, because of the greater risk of hypotension [see Warnings and Precautions (5.2)].
• Concomitant use of riociguat, a guanylate cyclase stimulator. PDE-5 inhibitors, including sildenafil, may potentiate the hypotensive effects of riociguat.
• Known hypersensitivity to sildenafil or any component of the tablet, injection, or oral suspension. Hypersensitivity, including anaphylactic reaction, anaphylactic shock and anaphylactoid reaction, has been reported in association with the use of sildenafil.

5 WARNINGS AND PRECAUTIONS

5.1 Mortality with Pediatric Use

In a long-term trial in pediatric patients with PAH, an increase in mortality with increasing Sildenafil for Oral Suspension dose was observed. Deaths were first observed after about 1 year and causes of death were typical of patients with PAH. Use of Sildenafil for Oral Suspension, particularly chronic use, is not recommended in children [see Use in Specific Populations (8.4)].

5.2 Hypotension

Sildenafil has vasodilatory properties, resulting in mild and transient decreases in blood pressure. Before prescribing Sildenafil for Oral Suspension, carefully consider whether patients with certain underlying conditions could be adversely affected by such vasodilatory effects (e.g., patients on antihypertensive therapy or with resting hypotension [BP less than 90/50], fluid depletion, severe left ventricular outflow obstruction, or autonomic dysfunction). Monitor blood pressure when co-administering blood pressure lowering drugs with Sildenafil for Oral Suspension.

5.3 Worsening Pulmonary Vascular Occlusive Disease

Pulmonary vasodilators may significantly worsen the cardiovascular status of patients with pulmonary veno-occlusive disease (PVOD). Since there are no clinical data on administration of Sildenafil for Oral Suspension to patients with veno-occlusive disease, administration of Sildenafil for Oral Suspension to such patients is not recommended. Should signs of pulmonary edema occur when Sildenafil for Oral Suspension is administered, consider the possibility of associated PVOD.

5.4 Epistaxis

The incidence of epistaxis was 13% in patients taking Sildenafil for Oral Suspension with PAH secondary to CTD. This effect was not seen in idiopathic PAH (sildenafil 3%, placebo 2%) patients. The incidence of epistaxis was also higher in Sildenafil for Oral Suspension-treated patients with a concomitant oral vitamin K antagonist (9% versus 2% in those not treated with concomitant vitamin K antagonist).

The safety of Sildenafil for Oral Suspension is unknown in patients with bleeding disorders or active peptic ulceration.

5.5 Visual Loss

When used to treat erectile dysfunction, non-arteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision, has been reported postmarketing in temporal association with the use of phosphodiesterase type 5 (PDE-5) inhibitors, including sildenafil. 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. Based on published literature, the annual incidence of NAION is 2.5–11.8 cases per 100,000 males aged ≥ 50 per year in the general population.

An observational case-crossover study evaluated the risk of NAION when PDE-5 inhibitor use, as a class, occurred immediately before NAION onset (within 5 half-lives), compared to PDE-5 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 postmarketing reports, nor the association of PDE-5 inhibitor use and NAION in the observational studies, substantiate a causal relationship between PDE-5 inhibitor use and NAION [see Adverse Reactions (6.2].

Advise patients to seek immediate medical attention in the event of a sudden loss of vision in one or both eyes while taking PDE-5 inhibitors, including Sildenafil for Oral Suspension. Physicians should also discuss the increased risk of NAION with patients who have already experienced NAION in one eye, including whether such individuals could be adversely affected by use of vasodilators, such as PDE-5 inhibitors.

There are no controlled clinical data on the safety or efficacy of Sildenafil for Oral Suspension in patients with retinitis pigmentosa, a minority whom have genetic disorders of retinal phosphodiesterases. Prescribe sildenafil with caution in these patients.