PRECAUTIONS SECTION.

PRECAUTIONS. Granisetron is not drug that stimulates gastric or intestinal peristalsis. It should not be used instead of nasogastric suction. The use of granisetron in patients following abdominal surgery or in patients with chemotherapy-induced nausea and vomiting may mask progressive ileus and/or gastric distention.An adequate QT assessment has not been conducted, but QT prolongation has been reported with granisetron. Therefore, GRANISOL oral solution should be used with caution in patients with pre-existing arrhythmias or cardiac conduction disorders, as this might lead to clinical consequences. Patients with cardiac disease, on cardio-toxic chemotherapy, with concomitant electrolyte abnormalities and/or on concomitant medications that prolong the QT interval are particularly at risk.. Drug Interactions. Granisetron does not induce or inhibit the cytochrome P-450 drug-metabolizing enzyme system in vitro. There have been no definitive drug-drug interaction studies to examine pharmacokinetic or pharmacodynamic interaction with other drugs; however, in humans, Kytril injection has been safely administered with drugs representing benzodiazepines, neuroleptics, and anti-ulcer medications commonly prescribed with antiemetic treatments. Kytril injection also does not appear to interact with emetogenic cancer chemotherapies. Because granisetron is metabolized by hepatic cytochrome P-450 drug-metabolizing enzymes, inducers or inhibitors of these enzymes may change the clearance and, hence, the half-life of granisetron. No specific interaction studies have been conducted in anesthetized patients. In addition, the activity of the cytochrome P-450 subfamily 3A4 (involved in the metabolism of some of the main narcotic analgesic agents) is not modified by granisetron in vitro.In in vitro human microsomal studies, ketoconazole inhibited ring oxidation of granisetron. However, the clinical significance of in vivo pharmacokinetic interactions with ketoconazole is not known. In human pharmacokinetic study, hepatic enzyme induction with phenobarbital resulted in 25% increase in total plasma clearance of intravenous granisetron. The clinical significance of this change is not known.QT prolongation has been reported with granisetron. Use of GRANISOL oral solution in patients concurrently treated with drugs known to prolong the QT interval and/or are arrhythmogenic may result in clinical consequences.. Carcinogenesis, Mutagenesis, Impairment of Fertility. In 24-month carcinogenicity study, rats were treated orally with granisetron 1, or 50 mg/kg/day (6, 30 or 300 mg/m 2/day). The 50 mg/kg/day dose was reduced to 25 mg/kg/day (150 mg/m 2/day) during week 59 due to toxicity. For 50 kg person of average height (1.46 m2 body surface area), these doses represent 4, 20, and 101 times the recommended clinical dose (1.48 mg/m 2, oral) on body surface area basis. There was statistically significant increase in the incidence of hepatocellular carcinomas and adenomas in males treated with mg/kg/day (30 mg/m2/day, 20 times the recommended human dose based on body surface area) and above, and in females treated with 25 mg/kg/day (150 mg/m 2/day, 101 times the recommended human dose based on body surface area). No increase in liver tumors was observed at dose of mg/kg/day (6 mg/m 2/day, times the recommended human dose based on body surface area) in males and mg/kg/day (30 mg/m 2/day, 20 times the recommended human dose based on body surface area) in females. In 12-month oral toxicity study, treatment with granisetron 100 mg/kg/day (600 mg/m 2/day, 405 times the recommended human dose based on body surface area) produced hepatocellular adenomas in male and female rats while no such tumors were found in the control rats. 24-month mouse carcinogenicity study of granisetron did not show statistically significant increase in tumor incidence, but the study was not conclusive. Because of the tumor findings in rat studies, granisetron should be prescribed only at the dose and for the indication recommended (see INDICATIONS AND USAGE and DOSAGE AND ADMINISTRATION). Granisetron was not mutagenic in the in vitro Ames test and mouse lymphoma cell forward mutation assay, and in vivo mouse micronucleus test and in vitro and ex vivo rat hepatocyte UDS assays. It, however, produced significant increase in UDS in HeLa cells in vitro and significant increased incidence of cells with polyploidy in an in vitro human lymphocyte chromosomal aberration test.Granisetron at oral doses up to 100 mg/kg/day (600 mg/m 2/day, 405 times the recommended human dose based on body surface area) was found to have no effect on fertility and reproductive performance of male and female rats. Pregnancy. Teratogenic EffectsPregnancy Category BReproduction studies have been performed in pregnant rats at oral doses up to 125 mg/kg/day (750 mg/m 2/day, 507 times the recommended human dose based on body surface area) and pregnant rabbits at oral doses up to 32 mg/kg/day (378 mg/m 2/day, 255 times the recommended human dose based on body surface area) and have revealed no evidence of impaired fertility or harm to the fetus due to granisetron. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Nursing Mothers. It is not known whether granisetron is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when granisetron is administered to nursing woman.. Pediatric Use. Safety and effectiveness in pediatric patients have not been established.. Geriatric Use. During clinical trials, 325 patients 65 years of age or older received Kytril tablets; 298 were 65 to 74 years of age, and 27 were 75 years of age or older. Efficacy and safety were maintained with increasing age.

ADVERSE REACTIONS SECTION.

ADVERSE REACTIONS. QT prolongation has been reported with granisetron (see PRECAUTIONSand Drug Interactions). Chemotherapy-Induced Nausea and VomitingOver 3700 patients have received Kytril tablets in clinical trials with emetogenic cancer therapies consisting primarily of cyclophosphamide or cisplatin regimens.In patients receiving Kytril tablets mg bid for 1, or 14 days, or mg daily for day, adverse experiences reported in more than 5% of the patients with comparator and placebo incidences are listed in Table 4. Table Principal Adverse Events in Clinical TrialsPercent of Patients With EventKytril Tablets mg twice day(n=978)Kytril Tablets mg once dayN=1450)Comparator (n=599)Placebo(n=185)Headache 21%20%13%12%Constipation18%14%16%8%Asthenia14%18%10%45Diarrhea8%9%10%4%Abdominal Pain6%4%6%3%Dyspepsia4%6%5%4%1Adverse events were recorded for days when Kytril tablets were given on single day and for up to 28 days when Kytril tablets were administered for or 14 days. 2Metoclopramide/dexamethasone; phenothiazines/dexamethasone; dexamethasone alone; prochlorperazine. 3Usually mild to moderate in severity. Other adverse events reported in clinical trials were:Gastrointestinal: In single-day dosing studies in which adverse events were collected for days, nausea (20%) and vomiting (12%) were recorded as adverse events after the 24-hour efficacy assessment period. Hepatic: In comparative trials, elevation of AST and ALT (> times the upper limit of normal) following the administration of Kytril tablets occurred in 5% and 6% of patients, respectively. These frequencies were not significantly different from those seen with comparators (AST: 2%; ALT: 9%). Cardiovascular: Hypertension (1%); hypotension, angina pectoris, atrial fibrillation, and syncope have been observed rarely. Central Nervous System: Dizziness (5%), insomnia (5%), anxiety (2%), somnolence (1%). One case compatible with, but not diagnostic of, extrapyramidal symptoms has been reported in patient treated with Kytril tablets.Hypersensitivity: Rare cases of hypersensitivity reactions, sometimes severe (eg, anaphylaxis, shortness of breath, hypotension, urticaria) have been reported. Other: Fever (5%). Events often associated with chemotherapy also have been reported: leukopenia (9%), decreased appetite (6%), anemia (4%), alopecia (3%), thrombocytopenia (2%). Over 5000 patients have received injectable Kytril in clinical trials.Table gives the comparative frequencies of the five commonly reported adverse events (>=3%) in patients receiving Kytril injection, 40 mcg/kg, in single-day chemotherapy trials. These patients received chemotherapy, primarily cisplatin, and intravenous fluids during the 24-hour period following Kytril injection administration. Table Principal Adverse Events in Clinical Trials Single-Day ChemotherapyPercent of Patients With EventKytril Injection 40 mcg/kg(n=1268)Comparator (n=422)Headache14%6%Asthenia5%6%Somnolence4%15%Diarrhea4%6%Constipation3%3%1Adverse events were generally recorded over days post-Kytril injection administration. 2Metoclopramide/dexamethasone and phenothiazines/dexamethasone.

PHARMACOKINETICS SECTION.

Pharmacokinetics. In healthy volunteers and adult cancer patients undergoing chemotherapy, administration of Kytril tablets produced mean pharmacokinetic data shown in Table 1. Table Pharmacokinetic Parameters (Median [range]) Following Kytril Tablets1Not determined after oral administration; following single intravenous dose of 40 mcg/kg, terminal phase half-life was determined to be 8.95 hours. N.D. Not determined.Peak Plasma Concentration(ng/mL)Terminal Phase Half-Life(h) Volume of Distribution(L/kg)Total Clearance(L/h/kg)Cancer Patients1 mg bid, days(n=27)5.99[0.63 to 30.9]N.D. N.D.0.52[0.09 to 7.37]VolunteersSingle mg dose(n=39)3.63[0.27 to 9.14]6.23 [0.96 to 19.9] 3.94 [1.89 to 39.4] 0.41 [0.11 to 24.6] 2 mg dose of GRANISOL oral solution is bioequivalent to the corresponding dose of Kytril tablets (1 mg 2) and may be used interchangeably.AbsorptionWhen Kytril tablets were administered with food, AUC was decreased by 5% and maxincreased by 30% in non-fasted healthy volunteers who received single dose of 10 mg. DistributionPlasma protein binding is approximately 65% and granisetron distributes freely between plasma and red blood cells.MetabolismGranisetron metabolism involves N-demethylation and aromatic ring oxidation followed by conjugation. In vitro liver microsomal studies show that granisetrons major route of metabolism is inhibited by ketoconazole, suggestive of metabolism mediated by the cytochrome P-450 3A subfamily. Animal studies suggest that some of the metabolites may also have 5-HT receptor antagonist activity. EliminationClearance is predominantly by hepatic metabolism. In normal volunteers, approximately 11% of the orally administered dose is eliminated unchanged in the urine in 48 hours. The remainder of the dose is excreted as metabolites, 48% in the urine and 38% in the feces.SubpopulationsGenderThe effects of gender on the pharmacokinetics of Kytril tablets have not been studied. However, after intravenous infusion of granisetron, no difference in mean AUC was found between males and females, although males had higher max generally. In elderly and pediatric patients and in patients with renal failure or hepatic impairment, the pharmacokinetics of granisetron was determined following administration of intravenous Kytril.ElderlyThe ranges of the pharmacokinetic parameters in elderly volunteers (mean age 71 years), given single 40-mcg/kg intravenous dose of Kytril injection, were generally similar to those in younger healthy volunteers; mean values were lower for clearance and longer for half-life in the elderly.Renal Failure PatientsTotal clearance of granisetron was not affected in patients with severe renal failure who received single 40 mcg/kg intravenous dose of Kytril injection.Hepatically Impaired PatientsA pharmacokinetic study with intravenous Kytril in patients with hepatic impairment due to neoplastic liver involvement showed that total clearance was approximately halved compared to patients without hepatic impairment. Given the wide variability in pharmacokinetic parameters noted in patients, dosage adjustment in patients with possible hepatic functional impairment is not necessary.Pediatric PatientsA pharmacokinetic study in pediatric cancer patients (2 to 16 years of age), given single 40 mcg/kg intravenous dose of Kytril injection, showed that volume of distribution and total clearance increased with age. No relationship with age was observed for peak plasma concentration or terminal phase plasma half-life. When volume of distribution and total clearance are adjusted for body weight, the pharmacokinetics of granisetron are similar in pediatric and adult cancer patients.

CARCINOGENESIS & MUTAGENESIS & IMPAIRMENT OF FERTILITY SECTION.

Carcinogenesis, Mutagenesis, Impairment of Fertility. In 24-month carcinogenicity study, rats were treated orally with granisetron 1, or 50 mg/kg/day (6, 30 or 300 mg/m 2/day). The 50 mg/kg/day dose was reduced to 25 mg/kg/day (150 mg/m 2/day) during week 59 due to toxicity. For 50 kg person of average height (1.46 m2 body surface area), these doses represent 4, 20, and 101 times the recommended clinical dose (1.48 mg/m 2, oral) on body surface area basis. There was statistically significant increase in the incidence of hepatocellular carcinomas and adenomas in males treated with mg/kg/day (30 mg/m2/day, 20 times the recommended human dose based on body surface area) and above, and in females treated with 25 mg/kg/day (150 mg/m 2/day, 101 times the recommended human dose based on body surface area). No increase in liver tumors was observed at dose of mg/kg/day (6 mg/m 2/day, times the recommended human dose based on body surface area) in males and mg/kg/day (30 mg/m 2/day, 20 times the recommended human dose based on body surface area) in females. In 12-month oral toxicity study, treatment with granisetron 100 mg/kg/day (600 mg/m 2/day, 405 times the recommended human dose based on body surface area) produced hepatocellular adenomas in male and female rats while no such tumors were found in the control rats. 24-month mouse carcinogenicity study of granisetron did not show statistically significant increase in tumor incidence, but the study was not conclusive. Because of the tumor findings in rat studies, granisetron should be prescribed only at the dose and for the indication recommended (see INDICATIONS AND USAGE and DOSAGE AND ADMINISTRATION). Granisetron was not mutagenic in the in vitro Ames test and mouse lymphoma cell forward mutation assay, and in vivo mouse micronucleus test and in vitro and ex vivo rat hepatocyte UDS assays. It, however, produced significant increase in UDS in HeLa cells in vitro and significant increased incidence of cells with polyploidy in an in vitro human lymphocyte chromosomal aberration test.Granisetron at oral doses up to 100 mg/kg/day (600 mg/m 2/day, 405 times the recommended human dose based on body surface area) was found to have no effect on fertility and reproductive performance of male and female rats.

CLINICAL PHARMACOLOGY SECTION.

CLINICAL PHARMACOLOGY. Granisetron is selective 5-hydroxytryptamine (5-HT 3) receptor antagonist with little or no affinity for other serotonin receptors, including 5-HT 1; 5-HT 1A; 5-HT 1B/C; 5-HT 2; for alpha 1-, alpha 2-, or beta-adrenoreceptors; for dopamine-D 2; or for histamine-H 1; benzodiazepine; picrotoxin or opioid receptors. Serotonin receptors of the 5-HT type are located peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema. During chemotherapy that induces vomiting, mucosal enterochromaffin cells release serotonin, which stimulates 5-HT receptors. This evokes vagal afferent discharge, inducing vomiting. Animal studies demonstrate that, in binding to 5-HT receptors, granisetron blocks serotonin stimulation and subsequent vomiting after emetogenic stimuli such as cisplatin. In the ferret animal model, single granisetron injection prevented vomiting due to high-dose cisplatin or arrested vomiting within to 30 seconds. In most human studies, granisetron has had little effect on blood pressure, heart rate or ECG. No evidence of an effect on plasma prolactin or aldosterone concentrations has been found in other studies.Following single and multiple oral doses, Kytril tablets slowed colonic transit in normal volunteers. However, granisetron had no effect on oro-cecal transit time in normal volunteers when given as single intravenous (IV) infusion of 50 mcg/kg or 200 mcg/kg.. Pharmacokinetics. In healthy volunteers and adult cancer patients undergoing chemotherapy, administration of Kytril tablets produced mean pharmacokinetic data shown in Table 1. Table Pharmacokinetic Parameters (Median [range]) Following Kytril Tablets1Not determined after oral administration; following single intravenous dose of 40 mcg/kg, terminal phase half-life was determined to be 8.95 hours. N.D. Not determined.Peak Plasma Concentration(ng/mL)Terminal Phase Half-Life(h) Volume of Distribution(L/kg)Total Clearance(L/h/kg)Cancer Patients1 mg bid, days(n=27)5.99[0.63 to 30.9]N.D. N.D.0.52[0.09 to 7.37]VolunteersSingle mg dose(n=39)3.63[0.27 to 9.14]6.23 [0.96 to 19.9] 3.94 [1.89 to 39.4] 0.41 [0.11 to 24.6] 2 mg dose of GRANISOL oral solution is bioequivalent to the corresponding dose of Kytril tablets (1 mg 2) and may be used interchangeably.AbsorptionWhen Kytril tablets were administered with food, AUC was decreased by 5% and maxincreased by 30% in non-fasted healthy volunteers who received single dose of 10 mg. DistributionPlasma protein binding is approximately 65% and granisetron distributes freely between plasma and red blood cells.MetabolismGranisetron metabolism involves N-demethylation and aromatic ring oxidation followed by conjugation. In vitro liver microsomal studies show that granisetrons major route of metabolism is inhibited by ketoconazole, suggestive of metabolism mediated by the cytochrome P-450 3A subfamily. Animal studies suggest that some of the metabolites may also have 5-HT receptor antagonist activity. EliminationClearance is predominantly by hepatic metabolism. In normal volunteers, approximately 11% of the orally administered dose is eliminated unchanged in the urine in 48 hours. The remainder of the dose is excreted as metabolites, 48% in the urine and 38% in the feces.SubpopulationsGenderThe effects of gender on the pharmacokinetics of Kytril tablets have not been studied. However, after intravenous infusion of granisetron, no difference in mean AUC was found between males and females, although males had higher max generally. In elderly and pediatric patients and in patients with renal failure or hepatic impairment, the pharmacokinetics of granisetron was determined following administration of intravenous Kytril.ElderlyThe ranges of the pharmacokinetic parameters in elderly volunteers (mean age 71 years), given single 40-mcg/kg intravenous dose of Kytril injection, were generally similar to those in younger healthy volunteers; mean values were lower for clearance and longer for half-life in the elderly.Renal Failure PatientsTotal clearance of granisetron was not affected in patients with severe renal failure who received single 40 mcg/kg intravenous dose of Kytril injection.Hepatically Impaired PatientsA pharmacokinetic study with intravenous Kytril in patients with hepatic impairment due to neoplastic liver involvement showed that total clearance was approximately halved compared to patients without hepatic impairment. Given the wide variability in pharmacokinetic parameters noted in patients, dosage adjustment in patients with possible hepatic functional impairment is not necessary.Pediatric PatientsA pharmacokinetic study in pediatric cancer patients (2 to 16 years of age), given single 40 mcg/kg intravenous dose of Kytril injection, showed that volume of distribution and total clearance increased with age. No relationship with age was observed for peak plasma concentration or terminal phase plasma half-life. When volume of distribution and total clearance are adjusted for body weight, the pharmacokinetics of granisetron are similar in pediatric and adult cancer patients.

CLINICAL TRIALS EXPERIENCE SECTION.

CLINICAL TRIALS. Chemotherapy-Induced Nausea and VomitingKytril tablets prevent nausea and vomiting associated with initial and repeat courses of emetogenic cancer therapy, as shown by 24-hour efficacy data from studies using both moderately- and highly-emetogenic chemotherapy.Moderately Emetogenic ChemotherapyThe first trial compared Kytril tablets doses of 0.25 mg to mg twice day, in 930 cancer patients receiving, principally, cyclophosphamide, carboplatin, and cisplatin (20 mg/m to 50 mg/m 2). Efficacy was based on complete response (i.e., no vomiting, no moderate or severe nausea, no rescue medication), no vomiting, and no nausea. Table summarizes the results of this study. Table Prevention of Nausea and Vomiting 24 Hours Post-Chemotherapy Percentages of PatientsKytril Tablet DoseEfficacy Measures0.25 mg twice day(n=229)%0.5 mg twice day(n=235)%1 mg twice day(n=233)%2 mg twice day(n=233)%Complete Response 617081 72No Vomiting66778879No Nausea485763541Chemotherapy included oral and injectable cyclophosphamide, carboplatin, cisplatin (20 mg/m to 50 mg/m 2), dacarbazine, doxorubicin, epirubicin. 2No vomiting, no moderate or severe nausea, no rescue medication. Statistically significant (P 0.01) vs. 0.25 mg twice day.+ Statistically significant (P 0.01) vs. 0.5 mg twice day. Results from second double-blind, randomized trial evaluating Kytril tablets mg once day and Kytril tablets mg twice day were compared to prochlorperazine 10 mg twice day derived from historical control. At 24 hours, there was no statistically significant difference in efficacy between the two Kytril tablet regimens. Both regimens were statistically superior to the prochlorperazine control regimen (see Table 3). Table Prevention of Nausea and Vomiting 24 Hours Post-Chemotherapy Percentage of PatientsEfficacy MeasuresKytril Tablets1 mg twice day(n=354)%Kytril Tablets2 mg once day(n=343)%Prochlorperazine 10 mg twice daily(n=111)%Complete Response 696441No Vomiting827748No Nausea515335Total Control 5150331Moderately emetogenic chemotherapeutic agents included cisplatin (20 mg/m to 50 mg/m 2), oral and intravenous cyclophosphamide, carboplatin, dacarbazine, doxorubicin. 2Historical control from previous double-blind granisetron trial. 3No vomiting, no moderate or severe nausea, no rescue medication. 4No vomiting, no nausea, no rescue medication. Statistically significant (P 0.05) vs. prochlorperazine historical control.Results from Kytril tablets mg daily alone treatment arm in third double-blind, randomized trial, were compared to prochlorperazine (PCPZ), 10 mg bid, derived from historical control. The 24-hour results for Kytril tablets mg daily were statistically superior to PCPZ for all efficacy parameters: complete response (58%), no vomiting (79%), no nausea (51%), total control (49%). The PCPZ rates are shown in Table 3. Cisplatin-Based ChemotherapyThe first double-blind trial compared Kytril tablets mg bid, relative to placebo (historical control), in 119 cancer patients receiving high-dose cisplatin (mean dose 80 mg/m2). At 24 hours, Kytril tablets mg bid was significantly (P 0.001) superior to placebo (historical control) in all efficacy parameters: complete response (52%), no vomiting (56%) and no nausea (45%). The placebo rates were 7%, 14%, and 7%, respectively, for the three efficacy parameters.Results from Kytril mg once day alone treatment arm in second double-blind, randomized trial, were compared to both Kytril tablets mg twice day and placebo historical controls. The 24-hour results for Kytril mg once day were: complete response (44%), no vomiting (58%), no nausea (46%), total control (40%). The efficacy of Kytril tablets mg once day was comparable to tablets mg twice day and statistically superior to placebo. The placebo rates were 7%, 14%, 7%, and 7%, respectively, for the four parameters.No controlled study comparing granisetron injection with the oral formulation to prevent chemotherapy-induced nausea and vomiting has been performed.Radiation-Induced Nausea and VomitingTotal Body IrradiationIn double-blind randomized study, 18 patients receiving Kytril tablets, mg daily, experienced significantly greater antiemetic protection compared to patients in historical negative control group who received conventional (non-5-HT antagonist) antiemetics. Total body irradiation consisted of 11 fractions of 120 cGy administered over days, with three fractions on each of the first days, and two fractions on the fourth day. Kytril tablets were given one hour before the first radiation fraction of each day. Twenty-two percent (22%) of patients treated with Kytril tablets did not experience vomiting or receive rescue antiemetics over the entire 4-day dosing period, compared to 0% of patients in the historical negative control group (P 0.01).In addition, patients who received Kytril tablets also experienced significantly fewer emetic episodes during the first day of radiation and over the 4-day treatment period, compared to patients in the historical negative control group. The median time to the first emetic episode was 36 hours for patients who received Kytril tablets.Fractionated Abdominal RadiationThe efficacy of Kytril tablets, mg daily, was evaluated in double-blind, placebo-controlled randomized trial of 260 patients. Kytril tablets were given hour before radiation, composed of up to 20 daily fractions of 180 to 300 cGy each. The exceptions were patients with seminoma or those receiving whole abdomen irradiation who initially received 150 cGy per fraction. Radiation was administered to the upper abdomen with field size of at least 100 cm 2. The proportion of patients without emesis and those without nausea for Kytril tablets, compared to placebo, was statistically significant (P 0.0001) at 24 hours after radiation, irrespective of the radiation dose. Granisetron was superior to placebo in patients receiving up to 10 daily fractions of radiation, but was not superior to placebo in patients receiving 20 fractions.Patients treated with Kytril tablets (n=134) had significantly longer time to the first episode of vomiting (35 days vs. days, < 0.001) relative to those patients who received placebo (n=126), and significantly longer time to the first episode of nausea (11 days vs. day, < 0.001). Granisetron provided significantly greater protection from nausea and vomiting than placebo.

DOSAGE & ADMINISTRATION SECTION.

DOSAGE AND ADMINISTRATION. Emetogenic ChemotherapyThe recommended adult dosage of oral granisetron hydrochloride is mg once daily or mg twice daily. In the mg once-daily regimen, 10 mL of GRANISOL oral solution (2 teaspoonfuls, equivalent to mg of granisetron) are given up to hour before chemotherapy. In the mg twice-daily regimen, the first teaspoonful (5 mL) of GRANISOL oral solution is given up to hour before chemotherapy, and the second teaspoonful (5 mL) of GRANISOL oral solution, 12 hours after the first. Either regimen is administered only on the day(s) chemotherapy is given. Continued treatment, while not on chemotherapy, has not been found to be useful.Use in the Elderly, Renal Failure Patients or Hepatically Impaired PatientsNo dosage adjustment is recommended (see CLINICAL PHARMACOLOGY: Pharmacokinetics). Pediatric UseSafety and effectiveness in pediatric patients have not been established.Radiation (Either Total Body Irradiation or Fractionated Abdominal Radiation)The recommended adult dosage of oral granisetron hydrochloride is mg once daily. Ten milliliters of GRANISOL oral solution (2 teaspoonfuls, equivalent to mg of granisetron) are taken within hour of radiation.Pediatric UseSafety and effectiveness in pediatric patients have not been established.Use in the ElderlyNo dosage adjustment is recommended.

DRUG INTERACTIONS SECTION.

Drug Interactions. Granisetron does not induce or inhibit the cytochrome P-450 drug-metabolizing enzyme system in vitro. There have been no definitive drug-drug interaction studies to examine pharmacokinetic or pharmacodynamic interaction with other drugs; however, in humans, Kytril injection has been safely administered with drugs representing benzodiazepines, neuroleptics, and anti-ulcer medications commonly prescribed with antiemetic treatments. Kytril injection also does not appear to interact with emetogenic cancer chemotherapies. Because granisetron is metabolized by hepatic cytochrome P-450 drug-metabolizing enzymes, inducers or inhibitors of these enzymes may change the clearance and, hence, the half-life of granisetron. No specific interaction studies have been conducted in anesthetized patients. In addition, the activity of the cytochrome P-450 subfamily 3A4 (involved in the metabolism of some of the main narcotic analgesic agents) is not modified by granisetron in vitro.In in vitro human microsomal studies, ketoconazole inhibited ring oxidation of granisetron. However, the clinical significance of in vivo pharmacokinetic interactions with ketoconazole is not known. In human pharmacokinetic study, hepatic enzyme induction with phenobarbital resulted in 25% increase in total plasma clearance of intravenous granisetron. The clinical significance of this change is not known.QT prolongation has been reported with granisetron. Use of GRANISOL oral solution in patients concurrently treated with drugs known to prolong the QT interval and/or are arrhythmogenic may result in clinical consequences.

WARNINGS SECTION.

WARNINGS. Serotonin SyndromeThe development of serotonin syndrome has been reported with 5-HT3 receptor antagonists alone but particularly with concomitant use of serotonergic drugs (e.g., selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors, mirtazapine, fentanyl, lithium, tramadol, and intravenous methylene blue). Some of the reported cases were fatal. Serotonin syndrome occurring with overdose of another 5-HT3 receptor antagonist alone has also been reported. The majority of reports of serotonin syndrome related to 5-HT3 receptor antagonist use occurred in post-anesthesia care unit or an infusion center.Symptoms associated with serotonin syndrome may include mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). Patients should be monitored for the emergence of serotonin syndrome, especially with concomitant use of granisetron and other serotonergic drugs. If symptoms of serotonin syndrome occur, discontinue granisetron and initiate supportive treatment. Patients should be informed of the increased risk of serotonin syndrome, especially if granisetron is used concomitantly with other serotonergic drugs [see Drug Interactions].