Sildenafil 20 mg Tablet, Film Coated, 10-count

5 WARNINGS AND PRECAUTIONS • Increased mortality with increasing doses in pediatric patients. Not recommended for use in pediatric patients. ( 5.1 ) • Vasodilation effects may be more common in patients with hypotension or on antihypertensive therapy.

( 5.2 ) • Use in pulmonary veno-occlusive disease may cause pulmonary edema and is not recommended. ( 5.3 ) • Hearing or visual impairment: Seek medical attention if sudden decrease or loss of vision or hearing occurs. ( 5.5 , 5.6 ) • Pulmonary hypertension secondary to sickle cell disease: Sildenafil may cause serious vaso-occlusive crises.

( 5.9 )

5.1Mortality with Pediatric Use In a long-term trial in pediatric patients with PAH, an increase in mortality with increasing sildenafil dose was observed. Deaths were first observed after about 1 year and causes of death were typical of patients with PAH. Use of sildenafil, particularly chronic use, is not recommended in children [ see Use in Specific Populations (8.4) ].

5.2Hypotension Sildenafil has vasodilatory properties, resulting in mild and transient decreases in blood pressure. Before prescribing sildenafil, 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.

5.3Worsening 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 to patients with veno-occlusive disease, administration of sildenafil to such patients is not recommended. Should signs of pulmonary edema occur when sildenafil is administered, consider the possibility of associated PVOD.

5.4Epistaxis The incidence of epistaxis was 13% in patients taking sildenafil 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-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 is unknown in patients with bleeding disorders or active peptic ulceration.

5.5Visual 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…

6 ADVERSE REACTIONS The following serious adverse events are discussed elsewhere in the labeling: • Mortality with pediatric use[ see Warnings and Precautions (5.1 ) and Use in Specific Populations (8.4) ] • Hypotension [ see Warnings and Precautions (5.2) ] • Vision loss [ see Warnings and Precautions (5.5) ] • Hearing loss [ see Warnings and Precautions (5.6) ] • Priapism [ see Warnings and Precautions (5.8) ] • Vaso-occlusive crisis [ see Warnings and Precautions (5.9) ] Most common adverse reactions greater than or equal to 3% and more frequent than placebo were epistaxis, headache, dyspepsia, flushing, insomnia, erythema, dyspnea, and rhinitis.

(6.1, 6.2) To report SUSPECTED ADVERSE REACTIONS, contact Macleods Pharma USA, Inc., at 1-888-943-3210 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch

6.1Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Safety data of sildenafil in adults were obtained from the 12-week, placebo-controlled clinical study (Study 1) and an open-label extension study in 277 sildenafil-treated patients with PAH, WHO Group I [see Clinical Studies (14)] .

The overall frequency of discontinuation in sildenafil-treated patients on 20 mg three times a day was 3% and was the same for the placebo group. In Study 1, the adverse reactions that were reported by at least 3% of sildenafil-treated patients (20 mg three times a day) and were more frequent in sildenafil-treated patients than in placebo-treated patients are shown in Table 1. Adverse reactions were generally transient and mild to moderate in nature.

Table 1. Most Common Adverse Reactions in Patients with PAH in Study 1 (More Frequent in Sildenafil-Treated Patients than Placebo-Treated Patients and Incidence ≥3% in Sildenafil-Treated Patients) Placebo, % (n = 70) Sildenafil tablets 20 mg three times a day, % (n = 69) Placebo-Subtracted, % Epistaxis 1 9 8 Headache 39 46 7 Dyspepsia 7 13 6 Flushing 4 10 6 Insomnia 1 7 6 Erythema 1 6 5 Dyspnea exacerbated 3 7 4 Rhinitis 0 4 4 Diarrhea 6 9 3 Myalgia 4 7 3 Pyrexia 3 6 3 Gastritis 0 3 3 Sinusitis 0 3 3 Paresthesia 0 3 3 At doses higher than the recommended 20 mg three times a day, there was a greater incidence of some adverse reactions including flushing, diarrhea, myalgia and visual disturbances.

Visual disturbances were identified as mild and transient, and were predominately color-tinge to vision, but also increased sensitivity to light or blurred vision. The incidence of retinal hemorrhage with sildenafil 20 mg three times a day was 1.4% versus 0% placebo and for all sildenafil doses studied was 1.9% versus 0% placebo. The incidence of eye hemorrhage at both 20 mg three times a day and at all doses studied was 1.4% for sildenafil versus 1.4% for placebo.

The patients experiencing these reactions had risk factors for hemorrhage including concurrent anticoagulant therapy. In a placebo-controlled fixed dose titration study (Study 2) of sildenafil (starting with recommended dose of 20 mg and increased to 40 mg and then 80 mg all three times a day) as an adjunct to intravenous epoprostenol in patients with PAH, the adverse reactions that were more frequent in the sildenafil + epoprostenol group than in the epoprostenol group (greater than 6% difference) are shown in Table 2 [see Clinical Studies (14) ].

Table 2. Adverse Reactions (%) in patients with PAH in Study 2 (incidence in Sildenafil + Epoprostenol group at least 6% greater than Epoprostenol group) Sildenafil + Epoprostenol (n = 134) Epoprostenol (n = 131) (Sildenafil + Epoprostenol)minus Epoprostenol % Headache 57 34 23 Edema includes peripheral edema 25 13 14 Dyspepsia 16 2 14 Pain in extremity 17 6 11 Diarrhea 25 18 7 Nausea 25 18 7 Nasal congestion 9 2 7

6.2 Postmarketing Experience The following adverse reactio…

7 DRUG INTERACTIONS Nitrates Concomitant use of sildenafil with nitrates in any form is contraindicated [ see Contraindications (4) ]. Ritonavir and other Potent CYP3A Inhibitors Concomitant use of sildenafil with ritonavir and other potent CYP3A inhibitors is not recommended [ see Clinical Pharmacology (12.3) ]. Other drugs that reduce blood pressure Alpha blockers .

In drug-drug interaction studies, sildenafil (25 mg, 50 mg, or 100 mg) and the alpha-blocker doxazosin (4 mg or 8 mg) were administered simultaneously to patients with benign prostatic hyperplasia (BPH) stabilized on doxazosin therapy. In these study populations, mean additional reductions of supine systolic and diastolic blood pressure of 7/7 mmHg, 9/5 mmHg, and 8/4 mmHg, respectively, were observed. Mean additional reductions of standing blood pressure of 6/6 mmHg, 11/4 mmHg, and 4/5 mmHg, respectively, were also observed.

There were infrequent reports of patients who experienced symptomatic postural hypotension. These reports included dizziness and light-headedness, but not syncope. Amlodipine .

When sildenafil 100 mg oral was co-administered with amlodipine, 5 mg or 10 mg oral, to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic. Monitor blood pressure when co-administering blood pressure lowering drugs with sildenafil [ see Warnings and Precautions (5.2) ]. • Concomitant alpha-blockers or amlodipine: Note additive blood pressure lowering effects. (7) • Use with ritonavir and other potent CYP3A inhibitors: Not recommended.

(7, 12.3) • Concomitant PDE-5 inhibitors: Avoid use with Viagra or other PDE-5 inhibitors. (5.7)