Ondansetron

RECENT MAJOR CHANGES Warnings and Precautions, Myocardial Ischemia (5.4) 10/2021

1 INDICATIONS AND USAGE Ondansetron orally disintegrating tablets are indicated for the prevention of nausea and vomiting associated with: • highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 • initial and repeat courses of moderately emetogenic cancer chemotherapy • radiotherapy in patients receiving either total body irradiation, single high-dose fraction to the abdomen, or daily fractions to the abdomen Ondansetron orally disintegrating tablets also indicated for the prevention of postoperative nausea and/or vomiting. Ondansetron orally disintegrating tablets are a 5-HT 3 receptor antagonist indicated for the prevention of: • nausea and vomiting associated with highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 . (1) • nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy. (1) • nausea and vomiting associated with radiotherapy in patients receiving either total body irradiation, single high-dose fraction to the abdomen, or daily fractions to the abdomen. (1) • postoperative nausea and/or vomiting. (1)

DOSAGE AND ADMINISTRATION Instructions for Use/Handling Ondansetron Orally Disintegrating Tablets USP: Do not attempt to push ondansetron orally disintegrating tablets USP through the foil backing. With dry hands, PEEL BACK the foil backing of 1 blister and GENTLY remove the tablet. IMMEDIATELY place the ondansetron orally disintegrating tablet USP on top of the tongue where it will dissolve in seconds, then swallow with saliva. Administration with liquid is not necessary. Prevention of Nausea and Vomiting Associated With Highly Emetogenic Cancer Chemotherapy: The recommended adult oral dosage of ondansetron is 24 mg given as three 8-mg tablets administered 30 minutes before the start of single-day highly emetogenic chemotherapy, including cisplatin ≥50 mg/m 2 . Multiday, single-dose administration of a 24 mg dosage has not been studied. Pediatric Use: There is no experience with the use of a 24 mg dosage in pediatric patients. Geriatric Use: The dosage recommendation is the same as for the general population. Prevention of Nausea and Vomiting Associated With Moderately Emetogenic Cancer Chemotherapy: The recommended adult oral dosage is one 8-mg ondansetron tablet USP or one 8-mg ondansetron orally disintegrating tablet USP given twice a day. The first dose should be administered 30 minutes before the start of emetogenic chemotherapy, with a subsequent dose 8 hours after the first dose. One 8-mg ondansetron tablet USP or one 8-mg ondansetron orally disintegrating tablet USP should be administered twice a day (every 12 hours) for 1 to 2 days after completion of chemotherapy. Pediatric Use: For pediatric patients 12 years of age and older, the dosage is the same as for adults. For pediatric patients 4 through 11 years of age, the dosage is one 4-mg ondansetron tablet USP or one 4-mg ondansetron orally disintegrating tablet USP given 3 times a day. The first dose should be administered 30 minutes before the start of emetogenic chemotherapy, with subsequent doses 4 and 8 hours after the first dose. One 4-mg ondansetron tablet USP or one 4-mg ondansetron orally disintegrating tablet USP should be administered 3 times a day (every 8 hours) for 1 to 2 days after completion of chemotherapy. Geriatric Use: The dosage is the same as for the general population. Prevention of Nausea and Vomiting Associated With Radiotherapy, Either Total Body Irradiation, or Single High-Dose Fraction or Daily Fractions to the Abdomen: The recommended oral dosage is one 8-mg ondansetron tablet USP or one 8-mg ondansetron orally disintegrating tablet USP given 3 times a day. For total body irradiation , one 8-mg ondansetron tablet USP or one 8-mg ondansetron orally disintegrating tablet USP should be administered 1 to 2 hours before each fraction of radiotherapy administered each day. For single high-dose fraction radiotherapy to the abdomen , one 8-mg ondansetron tablet USP or one 8-mg ondansetron orally disintegrating tablet USP should be administered 1 to 2 hours before radiotherapy, with subsequent doses every 8 hours after the first dose for 1 to 2 days after completion of radiotherapy. For daily fractionated radiotherapy to the abdomen , one 8-mg ondansetron tablet USP or one 8-mg ondansetron orally disintegrating tablet USP should be administered 1 to 2 hours before radiotherapy, with subsequent doses every 8 hours after the first dose for each day radiotherapy is given. Pediatric Use: There is no experience with the use of ondansetron tablets USP or ondansetron orally disintegrating tablets USP in the prevention of postoperative nausea and vomiting in pediatric patients. Geriatric Use: The dosage recommendation is the same as for the general population. Postoperative Nausea and Vomiting: The recommended dosage is 16 mg given as two 8-mg ondansetron tablets USP or two 8-mg ondansetron orally disintegrating tablets USP 1 hour before induction of anesthesia. Pediatric Use: There is no experience with the use of ondansetron tablets USP or ondansetron o …

3 DOSAGE FORMS AND STRENGTHS Ondansetron Tablets, USP are oval, standard convex, film-coated tablets and are available in the following strengths: • 4 mg - white tablet with ‘4’ on one side and ‘G1’ logo on the other side • 8 mg - yellow tablet with ‘8’ on one side and ‘G1’ logo on the other side Ondansetron Orally Disintegrating Tablets, USP are white, circular, flat faced, uncoated tablets and are available in the following strengths: • 4 mg - ‘G’ engraved on one side and ‘4’ on the other side • 8 mg - ‘G’ engraved on one side and ‘8’ on the other side • Tablets: 4 mg and 8 mg. ( 3 ) • Orally Disintegrating Tablets: 4 mg and 8 mg. ( 3 )

4 CONTRAINDICATIONS Ondansetron orally disintegrating tablets are contraindicated in patients: • known to have hypersensitivity (e.g., anaphylaxis) to ondansetron or any of the components of the formulation [see Adverse Reactions (6.2) ] • receiving concomitant apomorphine due to the risk of profound hypotension and loss of consciousness Patients known to have hypersensitivity (e.g., anaphylaxis) to ondansetron or any components of the formulation. ( 4 ) • Concomitant use of apomorphine. ( 4 )

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: • Hypersensitivity Reactions [see Warnings and Precautions (5.1) ] • QT Prolongation [see Warnings and Precautions (5.2) ] • Serotonin Syndrome [see Warnings and Precautions (5.3) ] • Myocardial Ischemia [see Warnings and Precautions (5.4) ] • Masking of Progressive Ileus and Gastric Distension [see Warnings and Precautions (5.5) ] 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 Rising Pharma Holdings, Inc. at 1-844-874-7464 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 with rates in the clinical trials of another drug and may not reflect the rates observed in practice. The following adverse reactions have been reported in clinical trials of patients treated with ondansetron, the active ingredient of ondansetron orally disintegrating tablets. A causal relationship to therapy with ondansetron was unclear in many cases. Prevention of Chemotherapy-Induced Nausea and Vomiting The most common adverse reactions reported in greater than or equal to 4% of 300 adults receiving a single 24 mg dose of ondansetron orally in 2 trials for the prevention of nausea and vomiting associated with highly emetogenic chemotherapy (cisplatin greater than or equal to 50 mg/m 2 ) were: headache (11%) and diarrhea (4%). The most common adverse reactions reported in 4 trials in adults for the prevention of nausea and vomiting associated with moderately emetogenic chemotherapy (primarily cyclophosphamide-based regimens) are shown in Table 3. Table 3: Most Common Adverse Reactions in Adults 1 for the Prevention of Nausea and Vomiting Associated With Moderately Emetogenic Chemotherapy [Primarily Cyclophosphamide-based Regimens] 1. Reported in greater than or equal to 5% of patients treated with ondansetron orally disintegrating tablets and at a rate that exceeded placebo. Adverse Reaction Ondansetron Orally Disintegrating Tablets 8 mg Twice Daily (n = 242) Placebo (n = 262) Headache 58 (24%) 34 (13%) Malaise/Fatigue 32 (13%) 6 (2%) Constipation 22 (9%) 1 (< 1%) Diarrhea 15 (6%) 10 (4%) Less Common Adverse Reactions Central Nervous System: Extrapyramidal reactions (less than 1% of patients). Hepatic: Aspartate transaminase (AST) and/or alanine transaminase (ALT) values exceeded twice the upper limit of normal in approximately 1% to 2% of 723 patients receiving ondansetron and cyclophosphamide-based chemotherapy in U.S. clinical trials. The increases were transient and did not appear to be related to dose or duration of therapy. On repeat exposure, similar transient elevations in transaminase values occurred in some courses, but symptomatic hepatic disease did not occur. The role of cancer chemotherapy in these biochemical changes is unclear. Liver failure and death has been reported in cancer patients receiving concurrent medications, including potentially hepatotoxic cytotoxic chemotherapy and antibiotics. The etiology of the liver failure is unclear. Integumentary: Rash (approximately 1% of patients). Other (less than 2%): Anaphylaxis, bronchospasm, tachycardia, angina, hypokalemia, electrocardiographic alterations, vascular occlusive events, and grand mal seizures. Except for bronchospasm and anaphylaxis, the relationship to ondansetron is unclear. Prevention of Radiation-Induced Nausea and Vomiting The most common adverse reactions (greater than or equal to 2%) reported in patients recei …

Drug Interactions Ondansetron does not itself appear to induce or inhibit the cytochrome P-450 drug-metabolizing enzyme system of the liver (see CLINICAL PHARMACOLOGY, Pharmacokinetics ). 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. On the basis of available data, no dosage adjustment is recommended for patients on these drugs. Apomorphine Based on reports of profound hypotension and loss of consciousness when apomorphine was administered with ondansetron, concomitant use of apomorphine with ondansetron is contraindicated (see CONTRAINDICATIONS ). Phenytoin, Carbamazepine, and Rifampicin In patients treated with potent inducers of CYP3A4 (i.e., phenytoin, carbamazepine, and rifampicin), 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. 1,3 Serotonergic Drugs Serotonin syndrome (including altered mental status, autonomic instability, and neuromuscular symptoms) has been described following the concomitant use of 5-HT3 receptor antagonists and other serotonergic drugs, including selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs) (see WARNINGS ). Tramadol Although no pharmacokinetic drug interaction between ondansetron and tramadol has been observed, data from 2 small studies indicate that ondansetron may be associated with an increase in patient controlled administration of tramadol. 4,5 Chemotherapy Tumor response to chemotherapy in the P-388 mouse leukemia model is not affected by ondansetron. In humans, carmustine, etoposide, and cisplatin do not affect the pharmacokinetics of ondansetron. In a crossover study in 76 pediatric patients, I.V. ondansetron did not increase blood levels of high-dose methotrexate. Use in Surgical Patients The coadministration of ondansetron had no effect on the pharmacokinetics and pharmacodynamics of temazepam.

8 USE IN SPECIFIC POPULATIONS 8.1 Pregnancy Risk Summary Published epidemiological studies on the association between ondansetron use and major birth defects have reported inconsistent findings and have important methodological limitations that preclude conclusions about the safety of ondansetron use in pregnancy (see Data) . Available postmarketing data have not identified a drug-associated risk of miscarriage or adverse maternal outcomes. Reproductive studies in rats and rabbits did not show evidence of harm to the fetus when ondansetron was administered during organogenesis at approximately 6 and 24 times the maximum recommended human oral dose of 24 mg/day, based on body surface area(BSA), respectively (see Data) . The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, miscarriages, or other adverse outcomes. In the US general population, the estimated background risk of major birth defects and miscarriages in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Human Data Available data on ondansetron use in pregnant women from several published epidemiological studies preclude an assessment of a drug-associated risk of adverse fetal outcomes due to important methodological limitations, including the uncertainty of whether women who filled a prescription actually took the medication, the concomitant use of other medications or treatments, recall bias, and other unadjusted confounders. Ondansetron exposure in utero has not been associated with overall major congenital malformations in aggregate analyses. One large retrospective cohort study examined 1970 women who received a prescription for ondansetron during pregnancy and reported no association between ondansetron exposure and major congenital malformations, miscarriage, stillbirth, preterm delivery, infants of low birth weight, or infants small for gestational age. Two large retrospective cohort studies and one case-control study have assessed ondansetron exposure in the first trimester and risk of cardiovascular defects with inconsistent findings. Relative risks (RR) ranged from 0.97 (95% CI 0.86 to 1.10) to 1.62 (95% CI 1.04, 2.54). A subset analysis in one of the cohort studies observed that ondansetron was specifically associated with cardiac septal defects (RR 2.05, 95% CI 1.19, 3.28); however, this association was not confirmed in other studies. Several studies have assessed ondansetron and the risk of oral clefts with inconsistent findings. A retrospective cohort study of 1.8 million pregnancies in the US Medicaid Database showed an increased risk of oral clefts among 88,467 pregnancies in which oral ondansetron was prescribed in the first trimester (RR 1.24, 95% CI 1.03, 1.48), but no such association was reported with intravenous ondansetron in 23,866 pregnancies (RR 0.95, 95% CI 0.63, 1.43). In the subgroup of women who received both forms of administration, the RR was 1.07 (95% CI 0.59, 1.93). Two case-control studies, using data from birth defects surveillance programs, reported conflicting associations between maternal use of ondansetron and isolated cleft palate (OR 1.6 [95% CI 1.1, 2.3] and 0.5 [95% CI 0.3, 1.0]). It is unknown whether ondansetron exposure in utero in the cases of cleft palate occurred during the time of palate formation (the palate is formed between the 6th and 9th weeks of pregnancy). Animal Data In embryo-fetal development studies in rats and rabbits, pregnant animals received oral doses of ondansetron up to 15 mg/kg/day and 30 mg/kg/day, respectively, during the period of organogenesis. With the exception of a slight decrease in maternal body weight gain in the rabbits, there were no significant effects of ondansetron on the maternal animals or the development of the offspring. At doses of 15 mg/kg/day in rats and 30 mg/kg/day in rabbits, the maternal exposure margin was approximately 6 and 24 times the max …

12.1 Mechanism of Action Ondansetron is a selective 5-HT 3 receptor antagonist. While its mechanism of action has not been fully characterized, ondansetron is not a dopamine-receptor antagonist. Serotonin receptors of the 5-HT 3 type are present both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema. It is not certain whether ondansetron’s antiemetic action is mediated centrally, peripherally, or in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine. In humans, urinary 5-hydroxyindoleacetic acid (5-HIAA) excretion increases after cisplatin administration in parallel with the onset of emesis. The released serotonin may stimulate the vagal afferents through the 5-HT 3 receptors and initiate the vomiting reflex.

DESCRIPTION The active ingredient in ondansetron tablets USP is ondansetron hydrochloride (HCl) 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. Ondansetron HCl 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. Each 4-mg ondansetron tablet USP for oral administration contains ondansetron HCl USP dihydrate equivalent to 4 mg of ondansetron. Each 8-mg ondansetron tablet USP for oral administration contains ondansetron HCl USP dihydrate equivalent to 8 mg of ondansetron. Each 24-mg ondansetron tablet USP for oral administration contains ondansetron HCl USP dihydrate equivalent to 24 mg of ondansetron. Each tablet also contains the inactive ingredients colloidal silicon dioxide, hypromellose, iron oxide yellow (8 mg tablet only), iron oxide red (24 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 HCl Structural Formula Structural Formula of Ondansetron Base

OVERDOSAGE There is no specific antidote for ondansetron overdose. Patients should be managed with appropriate supportive therapy. Individual intravenous doses as large as 150 mg and total daily intravenous doses as large as 252 mg have been inadvertently administered without significant adverse events. These doses are more than 10 times the recommended daily dose. In addition to the adverse events listed above, the following events have been described in the setting of ondansetron overdose: “Sudden blindness” (amaurosis) of 2 to 3 minutes’ duration plus severe constipation occurred in 1 patient that was administered 72 mg of ondansetron intravenously as a single dose. Hypotension (and faintness) occurred in a patient that took 48 mg of ondansetron tablets. Following infusion of 32 mg over only a 4-minute period, a vasovagal episode with transient second-degree heart block was observed. In all instances, the events resolved completely. Pediatric cases consistent with serotonin syndrome have been reported after inadvertent oral overdoses of ondansetron (exceeding estimated ingestion of 5 mg/kg) in young children. Reported symptoms included somnolence, agitation, tachycardia, tachypnea, hypertension, flushing, mydriasis, diaphoresis, myoclonic movements, horizontal nystagmus, hyperreflexia, and seizure. Patients required supportive care, including intubation in some cases, with complete recovery without sequelae within 1 to 2 days.

16 HOW SUPPLIED/STORAGE AND HANDLING Ondansetron Tablets, USP • 4 mg (ondansetron hydrochloride, USP (dihydrate) equivalent to 4 mg of ondansetron), are white, oval, standard convex, film-coated tablets with ‘4’ on one side and ‘G1’ logo on the other side in: Bottles of 30 tablets (NDC 68462-105-30). Carton (NDC 68462-105-33) of 3 tablets (1 card with 3 unit-of-use blisters, NDC 68462-105-40). 8 mg (ondansetron hydrochloride, USP (dihydrate) equivalent to 8 mg of ondansetron), are yellow, oval, standard convex, film-coated tablets with ‘8’ on one side and ‘G1’ logo on the other side in: Bottles of 30 tablets (NDC 68462-106-30). Carton (NDC 68462-106-33) of 3 tablets (1 card with 3 unit-of-use blisters, NDC 68462-106-40). Bottles: Store at 20oC to 25oC (68oF to 77oF) [see USP Controlled Room Temperature]. Protect from light. Dispense in a tight, light-resistant container as defined in the USP. Cartons: Store at 20oC to 25oC (68oF to 77oF) [see USP Controlled Room Temperature]. Protect from light. Store blister in carton. Ondansetron Orally Disintegrating Tablets, USP • 4 mg (as 4 mg ondansetron base) are white, circular, flat faced, uncoated tablets with ‘G’ engraved on one side and ‘4’ on the other side in: Carton (NDC 68462-157-13) of 30 tablets (3 cards each with 10 unit-of-use blisters, NDC 68462-157-40). • 8 mg (as 8 mg ondansetron base) are white, circular, flat faced, uncoated tablets with ‘G’ engraved on one side and ‘8’ on the other side in: Carton (NDC 68462-158-11) of 10 tablets (1 card with 10 unit-of-use blisters, NDC 68462-158-40). Carton (NDC 68462-158-13) of 30 tablets (3 cards each with 10 unit-of-use blisters, NDC 68462-158-40). Store at 20°C to 25°C (68°F to 77°F) [see USP Controlled Room Temperature].