ONDANSETRON

The active ingredient in Ondansetron Tablets, USP is ondansetron hydrochloride, USP as the dihydrate, the racemic form of ondansetron and a selective blocking agent of the serotonin 5-HT 3 receptor type. Chemically it is (±) 1, 2, 3, 9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-one, monohydrochloride, dihydrate. It has the following structural formula: The empirical formula is C 18 H 19 N 3 O•HCl•2H 2 O, representing a molecular weight of 365.85 g/mol. Ondansetron hydrochloride, USP (dihydrate) is a white to off-white powder that is sparingly soluble in water and in alcohol; soluble in methanol, slightly soluble in isopropyl alcohol, and in dichloromethane; very slightly soluble in acetone, in chloroform and in ethyl acetate. The active ingredient in Ondansetron Orally Disintegrating Tablets, USP is ondansetron base, the racemic form of ondansetron, and a selective blocking agent of the serotonin 5-HT 3 receptor type. Chemically it is (±) 1, 2, 3, 9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-one. It has the following structural formula: The empirical formula is C 18 H 19 N 3 O representing a molecular weight of 293.4 g/mol. Each 4-mg Ondansetron Tablet, USP for oral administration contains ondansetron hydrochloride, USP (dihydrate) equivalent to 4 mg of ondansetron. Each 8-mg Ondansetron Tablet, USP for oral administration contains ondansetron hydrochloride, USP (dihydrate) equivalent to 8 mg of ondansetron. Each tablet also contains the inactive ingredients colloidal silicon dioxide, hypromellose, iron oxide yellow (8 mg tablet only), lactose monohydrate, magnesium stearate, microcrystalline cellulose, pregelatinized starch, titanium dioxide and triacetin. Each 4-mg Ondansetron Orally Disintegrating Tablet, USP for oral administration contains 4 mg ondansetron base. Each 8-mg Ondansetron Orally Disintegrating Tablet, USP for oral administration contains 8 mg ondansetron base. Each Ondansetron Orally Disintegrating Tablet, USP also contains the inactive ingredients aspartame, colloidal silicon dioxide, crospovidone, magnesium stearate, mannitol, sodium stearyl fumarate and strawberry flavor. Ondansetron Orally Disintegrating Tablets, USP are an orally administered formulation of ondansetron which rapidly disintegrates on the tongue and does not require water to aid dissolution or swallowing. This product disintegrates in approximately 60 seconds. Ondansetron Orally Disintegrating Tablets, USP meet USP Disintegration Test 2. structure-hcl structure-base

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The most common adverse reactions in adults for the: prevention of chemotherapy-induced (≥5%) are: headache, malaise/fatigue, constipation, diarrhea. ( 6.1) prevention of radiation-induced nausea and vomiting (≥2%) are: headache, constipation, and diarrhea. ( 6.1) prevention of postoperative nausea and vomiting (≥9%) are: headache and hypoxia. ( 6.1) To report SUSPECTED ADVERSE REACTIONS, contact Glenmark Pharmaceuticals Inc., USA at 1 (888) 721-7115 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

7.1 Serotonergic Drugs Serotonin syndrome (including altered mental status, autonomic instability, and neuromuscular symptoms) has been described following the concomitant use of 5-HT 3 receptor antagonists and other serotonergic drugs, including SSRIs and SNRIs. Monitor for the emergence of serotonin syndrome. If symptoms occur, discontinue ondansetron and initiate supportive treatment [see Warnings and Precautions ( 5.3 )] . 7.2 Drugs Affecting Cytochrome P-450 Enzymes Ondansetron does not itself appear to induce or inhibit the cytochrome P‑450 drug‑metabolizing enzyme system of the liver [see Clinical Pharmacology ( 12.3 )] . Because ondansetron is metabolized by hepatic cytochrome P‑450 drug‑metabolizing enzymes (CYP3A4, CYP2D6, CYP1A2), inducers or inhibitors of these enzymes may change the clearance and, hence, the half‑life of ondansetron. In patients treated with potent inducers of CYP3A4 (i.e., phenytoin, carbamazepine, and rifampin), the clearance of ondansetron was significantly increased and ondansetron blood concentrations were decreased. However, on the basis of available data, no dosage adjustment for ondansetron is recommended for patients on these drugs [see Clinical Pharmacology ( 12.3 )] . 7.3 Tramadol Although no pharmacokinetic drug interaction between ondansetron and tramadol has been observed, data from 2 small trials indicate that when used together, ondansetron may increase patient-controlled administration of tramadol. Monitor patients to ensure adequate pain control when ondansetron is administered with tramadol. 7.4 Chemotherapy Carmustine, etoposide, and cisplatin do not affect the pharmacokinetics of ondansetron. In a crossover trial in 76 pediatric patients, intravenous ondansetron did not increase systemic concentrations of high-dose methotrexate. 7.5 Alfentanil and Atracurium Ondansetron does not alter the respiratory depressant effects produced by alfentanil or the degree of neuromuscular blockade produced by atracurium. Interactions with general or local anesthetics have not been studied.