SUMANSETRON

Sumatriptan tablets USP contain sumatriptan (as the succinate), a selective 5-hydroxytryptamine 1 receptor subtype agonist. Sumatriptan succinate USP is chemically designated as 3-[2- (dimethylamino) ethyl]-N-methyl-indole-5-methanesulfonamide succinate (1:1), and it has the following structure: The molecular formula is C 14 H 21 N 3 O 2 S•C 4 H 6 O 4 , representing a molecular weight of 413.5. Sumatriptan succinate USP is a white to off-white powder that is readily soluble in water and in saline. Each sumatriptan tablet USP for oral administration contains 35, 70, or 140 mg of sumatriptan succinate USP equivalent to 25, 50, or 100 mg of sumatriptan, respectively. Each tablet also contains the inactive ingredients croscarmellose sodium, lactose anhydrous, lactose monohydrate, magnesium stearate, mannitol, microcrystalline cellulose, talc, titanium dioxide and triacetin. structure 11 DESCRIPTION The active ingredient in ondansetron tablets is ondansetron hydrochloride as the dihydrate, the racemic form of ondansetron and a selective blocking agent of the serotonin 5-HT3 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 molecular formula is C18H19N3O•HCl•2H2O, representing a molecular weight of 365.5. Ondansetron hydrochloride dihydrate is a white to off-white powder that is soluble in water and normal saline. Each 4 mg ondansetron tablet, USP for oral administration contains ondansetron hydrochloride dihydrate equivalent to 4 mg of ondansetron. Each 8 mg ondansetron tablet, USP for oral administration contains ondansetron hydrochloride dihydrate equivalent to 8 mg of ondansetron. Each tablet also contains the inactive ingredients croscarmellose sodium, hypromellose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, pregelatinized starch, titanium dioxide, triacetin, and iron oxide yellow (8 mg tablet only). This product meets USP Dissolution Test 3. 2

Sumatriptan tablets are indicated for the acute treatment of migraine attacks with or without aura in adults. Sumatriptan tablets are not intended for the prophylactic therapy of migraine or for use in the management of hemiplegic or basilar migraine (see CONTRAINDICATIONS ). Safety and effectiveness of sumatriptan tablets have not been established for cluster headache, which is present in an older, predominantly male population. 1 INDICATIONS AND USAGE Ondansetron 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 tablets are also indicated for the prevention of postoperative nausea and/or vomiting. Ondansetron tablets are a 5-HT 3 receptor antagonist indicated for the prevention of: • nausea and vomiting associated with highly emetogenic cancer chemotherapy, including cisplatin ≥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 )

In controlled clinical trials, single doses of 25, 50, or 100 mg of sumatriptan tablets were effective for the acute treatment of migraine in adults. There is evidence that doses of 50 and 100 mg may provide a greater effect than 25 mg (see CLINICAL TRIALS ). There is also evidence that doses of 100 mg do not provide a greater effect than 50 mg. Individuals may vary in response to doses of sumatriptan tablets. The choice of dose should therefore be made on an individual basis, weighing the possible benefit of a higher dose with the potential for a greater risk of adverse events. If the headache returns or the patient has a partial response to the initial dose, the dose may be repeated after 2 hours, not to exceed a total daily dose of 200 mg. If a headache returns following an initial treatment with sumatriptan succinate injection, additional single sumatriptan tablets (up to 100 mg/day) may be given with an interval of at least 2 hours between tablet doses. The safety of treating an average of more than 4 headaches in a 30-day period has not been established. Because of the potential of MAO-A inhibitors to cause unpredictable elevations in the bioavailability of oral sumatriptan, their combined use is contraindicated (see CONTRAINDICATIONS ). Hepatic disease/functional impairment may also cause unpredictable elevations in the bioavailability of orally administered sumatriptan. Consequently, if treatment is deemed advisable in the presence of liver disease, the maximum single dose should in general not exceed 50 mg (see CLINICAL PHARMACOLOGY for the basis of this recommendation). 2 DOSAGE AND ADMINISTRATION • See full prescribing information for the recommended dosage in adults and pediatrics ( 2 ) • Patients with severe hepatic impairment: do not exceed a total daily dose of 8 mg ( 2.2 , 8.6 ) 2.1 Dosage The recommended dosage regimens for adult and pediatric patients are described in Table 1 and Table 2, respectively. Table 1: Adult Recommended Dosage Regimen for Prevention of Nausea and Vomiting Indication Dosage Regimen Highly Emetogenic Cancer Chemotherapy A single 24 mg dose administered 30 minutes before the start of single-day highly emetogenic chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 Moderately Emetogenic Cancer Chemotherapy 8 mg administered 30 minutes before the start of chemotherapy, with a subsequent 8 mg dose 8 hours after the first dose. Then administer 8 mg twice a day (every 12 hours) for 1 to 2 days after completion of chemotherapy Radiotherapy For total body irradiation: 8 mg administered 1 to 2 hours before each fraction of radiotherapy each day. For single high-dose fraction radiotherapy to the abdomen: 8 mg administered 1 to 2 hours before radiotherapy, with subsequent 8 mg doses every 8 hours after the first dose for 1 to 2 days after completion of radiotherapy. For daily fractionated radiotherapy to the abdomen: 8 mg administered 1 to 2 hours before radiotherapy, with subsequent 8 mg doses every 8 hours after the first dose for each day radiotherapy is given. Postoperative 16 mg administered 1 hour before induction of anesthesia Table 2: Pediatric Recommended Dosage Regimen for Prevention of Nausea and Vomiting Indication Dosage Regimen Moderately Emetogenic Cancer Chemotherapy 12 to 17 years of age: 8 mg administered 30 minutes before the start of chemotherapy, with a subsequent 8 mg dose 4 and 8 hours after the first dose. Then administer 8 mg three times a day for 1 to 2 days after completion of chemotherapy. 4 to 11 years of age: 4 mg administered 30 minutes before the start of chemotherapy, with a subsequent 4 mg dose 4 and 8 hours after the first dose. Then administer 4 mg three times a day for 1 to 2 days after completion of chemotherapy. 2.2 Dosage in Hepatic Impairment In patients with severe hepatic impairment (Child-Pugh score of 10 or greater), do not exceed a total daily dose of 8 mg [see Use in Specific Populations (8.6 ), Clinical Pharmacology (12.3 )]. 3 DOSAGE FORMS AND STRENGTHS Ondansetron Tablets USP, are available in the following strengths: • 4 mg – white, oval, film-coated tablets engraved with "4" on one side and “NO” on other side. • 8 mg – yellow, oval, film-coated tablets engraved with "8" on one side and "NO" on the other side. • Tablets: 4 mg and 8 mg ( 3 )

Sumatriptan tablets should not be given to patients with history, symptoms, or signs of ischemic cardiac, cerebrovascular, or peripheral vascular syndromes. In addition, patients with other significant underlying cardiovascular diseases should not receive sumatriptane tablets. Ischemic cardiac syndromes include, but are not limited to, angina pectoris of any type (e.g., stable angina of effort, vasospastic forms of angina such as the Prinzmetal variant), all forms of myocardial infarction, and silent myocardial ischemia. Cerebrovascular syndromes include, but are not limited to, strokes of any type as well as transient ischemic attacks. Peripheral vascular disease includes, but is not limited to, ischemic bowel disease (see WARNINGS ). Because sumatriptan tablets may increase blood pressure, they should not be given to patients with uncontrolled hypertension. Concurrent administration of MAO-A inhibitors or use within 2 weeks of discontinuation of MAO-A inhibitor therapy is contraindicated (see CLINICAL PHARMACOLOGY: Drug Interactions and PRECAUTIONS: Drug Interactions ). Sumatriptan tablets should not be administered to patients with hemiplegic or basilar migraine. Sumatriptan tablets and any ergotamine-containing or ergot-type medication (like dihydroergotamine or methysergide) should not be used within 24 hours of each other, nor should sumatriptan and another 5-HT 1 agonist. Sumatriptan tablets are contraindicated in patients with hypersensitivity to sumatriptan or any of their components. Sumatriptan tablets are contraindicated in patients with severe hepatic impairment. 4 CONTRAINDICATIONS Ondansetron 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 )

Serious cardiac events, including some that have been fatal, have occurred following the use of sumatriptan succinate injection or tablets. These events are extremely rare and most have been reported in patients with risk factors predictive of CAD. Events reported have included coronary artery vasospasm, transient myocardial ischemia, myocardial infarction, ventricular tachycardia, and ventricular fibrillation (see CONTRAINDICATIONS , WARNINGS , and PRECAUTIONS ) . Significant hypertensive episodes, including hypertensive crises, have been reported on rare occasions in patients with or without a history of hypertension (see WARNINGS ). Incidence in Controlled Clinical Trials Table 2 lists adverse events that occurred in placebo-controlled clinical trials in patients who took at least 1 dose of study drug. Only events that occurred at a frequency of 2% or more in any group treated with sumatriptan tablets and were more frequent in that group than in the placebo group are included in Table 2. The events cited reflect experience gained under closely monitored conditions of clinical trials in a highly selected patient population. In actual clinical practice or in other clinical trials, these frequency estimates may not apply, as the conditions of use, reporting behavior, and the kinds of patients treated may differ. Table 2. Treatment Emergent Adverse Events Reported by at Least 2% of Patients in Controlled Migraine Trials a Adverse Event Type Percent of Patients Reporting Placebo (N = 309) Sumatriptan 25 mg (N = 417) Sumatriptan 50 mg (N = 771) Sumatriptan 100 mg (N = 437) Atypical sensations 4% 5% 6% 6% Paresthesia (all types) 2% 3% 5% 3% Sensation warm/cold 2% 3% 2% 3% Pain and other pressure sensations 4% 6% 6% 8% Chest - pain/tightness/pressure and/or heaviness 1% 1% 2% 2% Neck/throat/jaw - pain/ tightness/pressure <1% <1% 2% 3% Pain - location specified 1% 2% 1% 1% Other - pressure/tightness/ heaviness 2% 1% 1% 3% Neurological Vertigo <1% <1% <1% 2% Other Malaise/fatigue <1% 2% 2% 3% a Events that occurred at a frequency of 2% or more in the group treated with sumatriptan tablets and that occurred more frequently in that group than the placebo group. Other events that occurred in more than 1% of patients receiving sumatriptan tablets and at least as often on placebo included nausea and/or vomiting, migraine, headache, hyposalivation, dizziness, and drowsiness/sleepiness. Sumatriptan tablets are generally well tolerated. Across all doses, most adverse reactions were mild and transient and did not lead to long-lasting effects. The incidence of adverse events in controlled clinical trials was not affected by gender or age of the patients. There were insufficient data to assess the impact of race on the incidence of adverse events. Other Events Observed in Association With the Administration of Sumatriptan Tablets In the paragraphs that follow, the frequencies of less commonly reported adverse clinical events are presented. Because the reports include events observed in open and uncontrolled studies, the role of sumatriptan tablets in their causation cannot be reliably determined. Furthermore, variability associated with adverse event reporting, the terminology used to describe adverse events, etc., limit the value of quantitative frequency estimates provided. Event frequencies are calculated as the number of patients who used sumatriptane tablets (25, 50, or 100 mg) and reported an event divided by the total number of patients (N = 6,348) exposed to sumatriptan tablets. All reported events are included except those already listed in the previous table, those too general to be informative, and those not reasonably associated with the use of the drug. Events are further classified within body system categories and enumerated in order of decreasing frequency using the following definitions: frequent adverse events are defined as those occurring in at least 1/100 patients, infrequent adverse events are those occurring in 1/100 to 1/1,000 patients, and rare adverse events are those occurring in fewer than 1/1,000 patients. Atypical Sensations Frequent were burning sensation and numbness. Infrequent was tight feeling in head. Rare were dysesthesia. Cardiovascular Frequent were palpitations, syncope, decreased blood pressure, and increased blood pressure. Infrequent were arrhythmia, changes in ECG, hypertension, hypotension, pallor, pulsating sensations, and tachycardia. Rare were angina, atherosclerosis, bradycardia, cerebral ischemia, cerebrovascular lesion, heart block, peripheral cyanosis, thrombosis, transient myocardial ischemia, and vasodilation. Ear, Nose, and Throat Frequent were sinusitis, tinnitus; allergic rhinitis; upper respiratory inflammation; ear, nose, and throat hemorrhage; external otitis; hearing loss; nasal inflammation; and sensitivity to noise. Infrequent were hearing disturbances and otalgia. Rare was feeling of fullness in the ear(s). Endocrine and Metabolic Infrequent was thirst. Rare were elevated thyrotropin stimulating hormone (TSH) levels; galactorrhea; hyperglycemia; hypoglycemia; hypothyroidism; polydipsia; weight gain; weight loss; endocrine cysts, lumps, and masses; and fluid disturbances. Eye Rare were disorders of sclera, mydriasis, blindness and low vision, visual disturbances, eye edema and swelling, eye irritation and itching, accommodation disorders, external ocular muscle disorders, eye hemorrhage, eye pain, and keratitis and conjunctivitis. Gastrointestinal Frequent were diarrhea and gastric symptoms. Infrequent were constipation, dysphagia, and gastroesophageal reflux. Rare were gastrointestinal bleeding, hematemesis, melena, peptic ulcer, gastrointestinal pain, dyspeptic symptoms, dental pain, feelings of gastrointestinal pressure, gastritis, gastroenteritis, hypersalivation, abdominal distention, oral itching and irritation, salivary gland swelling, and swallowing disorders. Hematological Disorders Rare was anemia. Musculoskeletal Frequent was myalgia. Infrequent was muscle cramps. Rare were tetany; muscle atrophy, weakness, and tiredness; arthralgia and articular rheumatitis; acquired musculoskeletal deformity; muscle stiffness, tightness, and rigidity; and musculoskeletal inflammation. Neurological Frequent were phonophobia and photophobia. Infrequent were confusion, depression, difficulty concentrating, disturbance of smell, dysarthria, euphoria, facial pain, heat sensitivity, incoordination, lacrimation, monoplegia, sleep disturbance, shivering, syncope, and tremor. Rare were aggressiveness, apathy, bradylogia, cluster headache, convulsions, decreased appetite, drug abuse, dystonic reaction, facial paralysis, hallucinations, hunger, hyperesthesia, hysteria, increased alertness, memory disturbance, neuralgia, paralysis, personality change, phobia, radiculopathy, rigidity, suicide, twitching, agitation, anxiety, depressive disorders, detachment, motor dysfunction, neurotic disorders, psychomotor disorders, taste disturbances, and raised intracranial pressure. Respiratory Frequent was dyspnea. Infrequent was asthma. Rare were hiccoughs, breathing disorders, cough, and bronchitis. Skin Frequent was sweating. Infrequent were erythema, pruritus, rash, and skin tenderness. Rare were dry/scaly skin, tightness of skin, wrinkling of skin, eczema, seborrheic dermatitis, and skin nodules. Breasts Infrequent was tenderness. Rare were nipple discharge; breast swelling; cysts, lumps, and masses of breasts; and primary malignant breast neoplasm. Urogenital Infrequent were dysmenorrhea, increased urination, and intermenstrual bleeding. Rare were abortion and hematuria, urinary frequency, bladder inflammation, micturition disorders, urethritis, urinary infections, menstruation symptoms, abnormal menstrual cycle, inflammation of fallopian tubes, and menstrual cycle symptoms. Miscellaneous Frequent was hypersensitivity. Infrequent were fever, fluid retention, and overdose. Rare were edema, hematoma, lymphadenopathy, speech disturbance, voice disturbances, contusions. Other Events Observed in the Clinical Development of Sumatriptan The following adverse events occurred in clinical trials with sumatriptan succinate injection and sumatriptan succinate nasal spray. Because the reports include events observed in open and uncontrolled studies, the role of sumatriptan in their causation cannot be reliably determined. All reported events are included except those already listed, those too general to be informative, and those not reasonably associated with the use of the drug. Atypical Sensations Feeling strange, prickling sensation, tingling, and hot sensation. Cardiovascular Abdominal aortic aneurysm, abnormal pulse, flushing, phlebitis, Raynaud syndrome, and various transient ECG changes (nonspecific ST or T wave changes, prolongation of PR or QTc intervals, sinus arrhythmia, nonsustained ventricular premature beats, isolated junctional ectopic beats, atrial ectopic beats, delayed activation of the right ventricle). Chest Symptoms Chest discomfort. Endocrine and Metabolic Dehydration. Ear, Nose, and Throat Disorder/discomfort nasal cavity and sinuses, ear infection, Meniere disease, and throat discomfort. Eye Vision alterations. Gastrointestinal Abdominal discomfort, colitis, disturbance of liver function tests, flatulence/eructation, gallstones, intestinal obstruction, pancreatitis, and retching. Injection Site Reaction Miscellaneous Difficulty in walking, hypersensitivity to various agents, jaw discomfort, miscellaneous laboratory abnormalities, “serotonin agonist effect,” swelling of the extremities, and swelling of the face. Mouth and Teeth Disorder of mouth and tongue (e.g., burning of tongue, numbness of tongue, dry mouth). Musculoskeletal Arthritis, backache, intervertebral disc disorder, neck pain/stiffness, need to flex calf muscles, and various joint disturbances (pain, stiffness, swelling, ache). Neurological Bad/unusual taste, chills, diplegia, disturbance of emotions, sedation, globus hystericus, intoxication, myoclonia, neoplasm of pituitary, relaxation, sensation of lightness, simultaneous hot and cold sensations, stinging sensations, stress, tickling sensations, transient hemiplegia, and yawning. Respiratory influenza and diseases of the lower respiratory tract and lower respiratory tract infection. Skin Skin eruption, herpes, and peeling of the skin. Urogenital Disorder of breasts, endometriosis, and renal calculus. Postmarketing Experience (Reports for Subcutaneous or Oral Sumatriptan) The following section enumerates potentially important adverse events that have occurred in clinical practice and that have been reported spontaneously to various surveillance systems. The events enumerated represent reports arising from both domestic and nondomestic use of oral or subcutaneous dosage forms of sumatriptan. The events enumerated include all except those already listed in the ADVERSE REACTIONS section above or those too general to be informative. Because the reports cite events reported spontaneously from worldwide postmarketing experience, frequency of events and the role of sumatriptan in their causation cannot be reliably determined. It is assumed, however, that systemic reactions following sumatriptan use are likely to be similar regardless of route of administration. Blood Hemolytic anemia, pancytopenia, thrombocytopenia. Cardiovascular Atrial fibrillation, cardiomyopathy, colonic ischemia (see WARNINGS ), Prinzmetal variant angina, pulmonary embolism, shock, thrombophlebitis. Ear, Nose, and Throat Deafness. Eye Ischemic optic neuropathy, retinal artery occlusion, retinal vein thrombosis, loss of vision. Gastrointestinal Ischemic colitis with rectal bleeding (see WARNINGS ), xerostomia. Hepatic Elevated liver function tests. Neurological Central nervous system vasculitis, cerebrovascular accident, dysphasia, serotonin syndrome, subarachnoid hemorrhage. Non-Site Specific Angioneurotic edema, cyanosis, death (see WARNINGS ), temporal arteritis. Psychiatry Panic disorder. Respiratory Bronchospasm in patients with and without a history of asthma. Skin Exacerbation of sunburn, hypersensitivity reactions (allergic vasculitis, erythema, pruritus, rash, shortness of breath, urticaria; in addition, severe anaphylaxis/anaphylactoid reactions have been reported [see WARNINGS ]), photosensitivity. Urogenital Acute renal failure. 6 ADVERSE REACTIONS The most common adverse reactions in adults for the: • prevention of chemotherapy-induced (greater than or equal to 5%) are: headache, malaise/fatigue, constipation, diarrhea. ( 6.1 ) • prevention of radiation-induced nausea and vomiting (greater than or equal to 2%) are: headache, constipation, and diarrhea. ( 6.1 ) • prevention of postoperative nausea and vomiting (greater than or equal to 9%) are: headache and hypoxia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Actavis Pharma Inc., at 1-800-432-8534 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 tablets. A causal relationship to therapy with ondansetron tablets 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 tablets 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 a for the Prevention of Nausea and Vomiting Associated with Moderately Emetogenic Chemotherapy [Primarily Cyclophosphamide-based Regimens] a Reported in greater than or equal to 5% of patients treated with ondansetron tablets and at a rate that exceeded placebo. Adverse Reaction Ondansetron 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 tablets and cyclophosphamide-based chemotherapy in US 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 tablets is unclear. Prevention of Radiation-induced Nausea and Vomiting The most common adverse reactions (greater than or equal to 2%) reported in patients receiving ondansetron tablets and concurrent radiotherapy were similar to those reported in patients receiving ondansetron tablets and concurrent chemotherapy and were headache, constipation, and diarrhea. Prevention of Postoperative Nausea and Vomiting The most common adverse reactions reported in adults in trial(s) of prevention of postoperative nausea and vomiting are shown in Table 4. In these trial(s) patients were receiving multiple concomitant perioperative and postoperative medications in both treatment groups. Table 4. Most Common Adverse Reactions in Adults a for the Prevention of Postoperative Nausea and Vomiting a Reported in greater than or equal to 5% of patients treated with ondansetron tablets and at a rate that exceeded placebo. Adverse Reaction Ondansetron Tablets 16 mg as a Single Dose (n = 550) Placebo (n = 531) Headache 49 (9%) 27 (5%) Hypoxia 49 (9%) 35 (7%) Pyrexia 45 (8%) 34 (6%) Dizziness 36 (7%) 34 (6%) Gynecological disorder 36 (7%) 33 (6%) Anxiety/agitation 33 (6%) 29 (5%) Urinary retention 28 (5%) 18 (3%) Pruritus 27 (5%) 20 (4%) 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of ondansetron. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiovascular Arrhythmias (including ventricular and supraventricular tachycardia, premature ventricular contractions, and atrial fibrillation), bradycardia, electrocardiographic alterations (including second-degree heart block, QT/QTc interval prolongation, and ST segment depression), palpitations, and syncope. Rarely and predominantly with intravenous ondansetron, transient ECG changes including QT interval prolongation have been reported. General Flushing. Rare cases of hypersensitivity reactions, sometimes severe (e.g., anaphylactic reactions, angioedema, bronchospasm, shortness of breath, hypotension, laryngeal edema, stridor) have also been reported. Laryngospasm, shock, and cardiopulmonary arrest have occurred during allergic reactions in patients receiving injectable ondansetron. Hepatobiliary Liver enzyme abnormalities. Lower Respiratory Hiccups. Neurology Oculogyric crisis, appearing alone, as well as with other dystonic reactions. Skin Urticaria, Stevens-Johnson syndrome, and toxic epidermal necrolysis. Eye Disorders Cases of transient blindness, predominantly during intravenous administration, have been reported. These cases of transient blindness were reported to resolve within a few minutes up to 48 hours.

Monoamine Oxidase Inhibitors (MAO) Treatment with MAO-A inhibitors generally leads to an increase of sumatriptan plasma levels (see CONTRAINDICATIONS and PRECAUTIONS ). Due to gut and hepatic metabolic first-pass effects, the increase of systemic exposure after coadministration of an MAO-A inhibitor with oral sumatriptan is greater than after coadministration of the monoamine oxidase inhibitors (MAOI) with subcutaneous sumatriptan. In a study of 14 healthy females, pretreatment with an MAO-A inhibitor decreased the clearance of subcutaneous sumatriptan. Under the conditions of this experiment, the result was a 2-fold increase in the area under the sumatriptan plasma concentration x time curve (AUC), corresponding to a 40% increase in elimination half-life. This interaction was not evident with an MAO-B inhibitor. A small study evaluating the effect of pretreatment with an MAO-A inhibitor on the bioavailability from a 25 mg oral sumatriptan tablet resulted in an approximately 7-fold increase in systemic exposure. Alcohol Alcohol consumed 30 minutes prior to sumatriptan ingestion had no effect on the pharmacokinetics of sumatriptan. Drug Interactions Selective Serotonin Reuptake Inhibitors/Serotonin Norepinephrine Reuptake Inhibitors and Serotonin Syndrome: Cases of life‑threatening serotonin syndrome have been reported during combined use of SSRIs or SNRIs and triptans (see WARNINGS ). Ergot-Containing Drugs Ergot-containing drugs have been reported to cause prolonged vasospastic reactions. Because there is a theoretical basis that these effects may be additive, use of ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and sumatriptan within 24 hours of each other should be avoided (see CONTRAINDICATIONS ). Monoamine Oxidase-A Inhibitors MAO-A inhibitors reduce sumatriptan clearance, significantly increasing systemic exposure. Therefore, the use of sumatriptan tablets in patients receiving MAO-A inhibitors is contraindicated (see CLINICAL PHARMACOLOGY and CONTRAINDICATIONS ). 7 DRUG INTERACTIONS 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 selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs). Monitor for the emergence of serotonin syndrome. If symptoms occur, discontinue ondansetron tablets 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 tablets 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 tablets 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 tablets do 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.