CILOSTAZOL: 1,475 Adverse Event Reports & Safety Profile

Cilostazol, USP is a quinolinone derivative that inhibits cellular phosphodiesterase (more specific for phosphodiesterase III). The empirical formula of cilostazol is C 20 H 27 N 5 O 2 , and its molecular weight is 369.46. Cilostazol is 6-[4-(1-cyclohexyl-1 H -tetrazol-5-yl)butoxy]-3,4-dihydro-2(1 H )-quinolinone, CAS-73963-72-1. The structural formula is: Cilostazol occurs as white to off-white crystals or as a crystalline powder that is slightly soluble in methanol and ethanol, and is practically insoluble in water, 0.1 N HCl, and 0.1 N NaOH.

Cilostazol

Tablets, USP for oral administration are available in 50 mg and 100 mg white to off white, round, flat faced, beveled edge, debossed tablets. Each tablet, in addition to the active ingredient, contains the following inactive ingredients: carboxymethyl cellulose calcium, magnesium stearate, methylcellulose, microcrystalline cellulose, pregelatinized starch, and purified water. image description

AND USAGE Cilostazol tablets are indicated for the reduction of symptoms of intermittent claudication, as demonstrated by an increased walking distance. Cilostazol tablets are a phosphodiesterase III inhibitor (PDE III inhibitor) indicated for the reduction of symptoms of intermittent claudication, as demonstrated by an increased walking distance ( 1 )

AND ADMINISTRATION The recommended dosage of cilostazol tablets is 100 mg twice daily taken at least half an hour before or two hours after breakfast and dinner ( 2.1 ) Reduce the dose to 50 mg twice daily when coadministered with CYP3A4 inhibitors such as ketoconazole, itraconazole, erythromycin, and diltiazem, or CYP2C19 inhibitors such as ticlopidine, fluconazole, and omeprazole ( 2.2 )

2.1 Recommended Dosage The recommended dosage of cilostazol tablets is 100 mg twice daily taken at least half an hour before or two hours after breakfast and dinner. Patients may respond as early as 2 to 4 weeks after the initiation of therapy, but treatment for up to 12 weeks may be needed before a beneficial effect is experienced. If symptoms are unimproved after 3 months, discontinue cilostazol tablets.

2.2 Dose Reduction with CYP3A4 and CYP2C19 Inhibitors Reduce dose to 50 mg twice daily when coadministered with strong or moderate inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, erythromycin, and diltiazem) or inhibitors of CYP2C19 (e.g., ticlopidine, fluconazole, and omeprazole) <span class="opacity-50 text-xs">[see Drug Interactions ( 7.1 )]</span> .

Cilostazol tablets are contraindicated in patients with: Heart failure of any severity: Cilostazol and several of its metabolites are inhibitors of phosphodiesterase III. Several drugs with this pharmacologic effect have caused decreased survival compared to placebo in patients with class III-IV heart failure. Hypersensitivity to cilostazol or any components of cilostazol tablets (e.g., anaphylaxis, angioedema) Heart failure of any severity ( 4 ) Hypersensitivity to cilostazol or any components of cilostazol tablets ( 4 )

REACTIONS The following adverse reactions are discussed in greater detail in other sections of the labeling: Patients with Heart Failure [see Boxed Warning] Tachycardia [see Warnings and Precautions ( 5.1 )]

Left Ventricular Outflow Tract

Obstruction [see Warnings and Precautions ( 5.2 )]

Hematologic Adverse

Reactions [see Warnings and Precautions ( 5.3 )]

Hemostatic

Disorders or Active Pathologic Bleeding [see Warnings and Precautions ( 5.4 )]

5.2 Most common adverse reactions greater than or equal to 2% and at least twice that for placebo in patients on 100 mg twice daily are headache, diarrhea, abnormal stools, and palpitation ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Apotex Inc. at 1-800-706-5575 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

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. Adverse reactions were assessed in eight placebo-controlled clinical trials involving patients exposed to either 50 or 100 mg twice daily cilostazol tablets (n=1301) or placebo (n=973), with a median treatment duration of 127 days for patients on cilostazol tablets and 134 days for patients on placebo. The most frequent adverse reaction resulting in discontinuation of therapy in more than 3% of patients treated with cilostazol tablets was headache [50 mg twice daily (1.3%), 100 mg twice daily (3.5%) and placebo (0.3%)]. Other frequent causes of discontinuation included palpitation and diarrhea, both 1.1% for cilostazol tablets (all doses) versus 0.1% for placebo. The most common adverse reactions, occurring in at least 2% of patients treated with cilostazol tablets 50 or 100 mg twice daily, are shown in Table 1.

Table

1: Most Common Adverse Reactions in Patients on cilostazol tablets 50 or 100 mg Twice Daily (Incidence at least 2% and Occurring More Frequently (≥ 2%) in the 100 mg Twice Daily Group than on Placebo)

Adverse Reactions

Placebo (N=973) Cilostazol tablets 50 mg twice daily (N=303) Cilostazol tablets 100 mg twice daily (N=998)

Headache

14% 27% 34% Diarrhea 7% 12% 19% Abnormal stools 4% 12% 15% Palpitation 1% 5% 10% Dizziness 6% 9% 10% Pharyngitis 7% 7% 10% Infection 8% 14% 10% Peripheral edema 4% 9% 7% Rhinitis 5% 12% 7% Dyspepsia 4% 6% 6% Abdominal pain 3% 4% 5% Tachycardia 1% 4% 4% Less frequent clinical significant adverse reactions (less than 2%) that were experienced by patients treated with cilostazol 50 mg twice daily or 100 mg twice daily in the eight controlled clinical trials and that occurred at a frequency in the 100 mg twice daily group greater than in the placebo group are listed below. Body as a whole: fever, generalized edema, malaise Cardiovascular: atrial fibrillation, heart failure, myocardial infarction, nodal arrhythmia, supraventricular tachycardia, ventricular extrasystoles, ventricular tachycardia Digestive: anorexia, melena Hematologic and Lymphatic: anemia Metabolic and Nutritional: increased creatinine, hyperuricemia Nervous: insomnia Respiratory: epistaxis Skin and Appendages: urticaria Special Senses: conjunctivitis, retinal hemorrhage, tinnitus Urogenital: urinary frequency

6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of cilostazol tablets. Because these reactions are reported voluntarily from a population of an unknown size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood and lymphatic system disorders: Aplastic anemia, granulocytopenia, pancytopenia, bleeding tendency Cardiac disorders: Torsade de pointes and QTc prolongation in patients with cardiac disorders (e.g. complete atrioventricular block, heart failure; and bradyarrythmia), angina pectoris. Gastrointestinal disorders: Gastrointestinal hemorrhage, vomiting, flatulence, nausea General disorders and administration site conditions: Pain, chest pain, hot flushes Hepatobiliary disorders: Hepatic dysfunction/abnormal liver function tests, jaundice Immune system disorders: Anaphylaxis, angioedema, and hypersensitivity Investigations: Blood glucose increased, blood uric acid increased, increase in BUN (blood urea increased), blood pressure increase Nervous system disorders: Intracranial hemorrhage, cerebral hemorrhage, cerebrovascular accident, extradural hematoma and subdural hematoma Renal and urinary disorders: Hematuria Respiratory, thoracic and mediastinal disorders: Pulmonary hemorrhage, interstitial pneumonia Skin and subcutaneous tissue disorders: Hemorrhage subcutaneous, pruritus, skin eruptions including Stevens-Johnson syndrome, skin drug eruption (dermatitis medicamentosa), rash Vascular disorders: Subacute stent thrombosis, hypertension. To report SUSPECTED ADVERSE REACTIONS contact AvKARE at 1-855-361-3993; email [email protected] ; or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

AND PRECAUTIONS Risks of tachycardia, palpitation, tachyarrhythmia or hypotension. Risks of exacerbations of angina pectoris or myocardial infarction in patients with a history of ischemic heart disease ( 5.2 ) Left ventricular outflow tract obstruction has been reported in patients with sigmoid shaped interventricular septum ( 5.1 ) Risks of thrombocytopenia or leukopenia progressing to agranulocytosis-monitor platelets and white blood cell counts ( 5.3 ) Avoid use in patients with hemostatic disorders or active pathologic bleeding ( 5.4 )

5.1 Tachycardia Cilostazol may induce tachycardia, palpitation, tachyarrhythmia or hypotension. The increase in heart rate associated with cilostazol is approximately 5 to 7 bpm. Patients with a history of ischemic heart disease may be at risk for exacerbations of angina pectoris or myocardial infarction.

5.2 Left Ventricular Outflow Tract Obstruction Left ventricular outflow tract obstruction has been reported in patients with sigmoid shaped interventricular septum. Monitor patients for the development of a new systolic murmur or cardiac symptoms after starting cilostazol.

5.3 Hematologic Adverse Reactions Cases of thrombocytopenia or leukopenia progressing to agranulocytosis when cilostazol was not immediately discontinued have been reported. Agranulocytosis is reversible on discontinuation of cilostazol. Monitor platelets and white blood cell counts periodically.

5.4 Hemostatic Disorders or Active Pathologic Bleeding Cilostazol inhibits platelet aggregation in a reversible manner. Cilostazol has not been studied in patients with hemostatic disorders or active pathologic bleeding. Avoid use of cilostazol tablets in these patients.

INTERACTIONS Strong and moderate CYP3A4 and CYP2C19 inhibitors: Increase exposure to cilostazol. Reduce cilostazol tablets dose ( 2.2 , 7.1 )

7.1 Inhibitors of CYP3A4 or CYP2C19 Inhibitors of CYP3A4 Coadministration of strong (e.g., ketoconazole) and moderate (e.g., erythromycin, diltiazem and grapefruit juice) CYP3A4 inhibitors can increase exposure to cilostazol. Reduce cilostazol dose to 50 mg twice daily when coadministered with strong or moderate inhibitors of CYP3A4 <span class="opacity-50 text-xs">[see Dosage and Administration ( 2.2 ) and Clinical Pharmacology ( 12.3 )]</span>. Inhibitors of CYP2C19 Coadministration with CYP2C19 inhibitors (e.g., omeprazole) increases systemic exposure of cilostazol active metabolites. Reduce cilostazol dose to 50 mg twice daily when coadministered with strong or moderate inhibitors of CYP2C19 <span class="opacity-50 text-xs">[see Dosage and Administration ( 2.2 ) and Clinical Pharmacology ( 12.3 )]</span>.