SILDENAFIL CITRATE (Page 2 of 8)

5.9 Vaso-occlusive Crisis in Patients with Pulmonary Hypertension Secondary to Sickle Cell Anemia

In a small, prematurely terminated study of patients with pulmonary hypertension (PH) secondary to sickle cell disease, vaso-occlusive crises requiring hospitalization were more commonly reported by patients who received sildenafil citrate than by those randomized to placebo. The effectiveness and safety of sildenafil citrate in the treatment of PAH secondary to sickle cell anemia has not been established.

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) ]

6.1 Clinical 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 citrate in adults were obtained from the 12-week, placebo-controlled clinical study (Study 1) and an open-label extension study in 277 sildenafil citrate-treated patients with PAH, WHO Group I [see Clinical Studies ( 14)] .

The overall frequency of discontinuation in sildenafil citrate-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 citrate-treated patients (20 mg three times a day) and were more frequent in sildenafil citrate-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 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 citrate (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 citrate + 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)

*includes peripheral edema
	Sildenafil + Epoprostenol (n = 134)	Epoprostenol (n = 131)	(Sildenafil + Epoprostenol) minus Epoprostenol
Headache	57	34	23
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