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ribavirin tablet, film coated
FULL PRESCRIBING INFORMATION
WARNING: RISK OF SERIOUS DISORDERS AND RIBAVIRIN-ASSOCIATED EFFECTS
Ribavirin monotherapy is not effective for the treatment of chronic hepatitis C virus infection and should not be used alone for this indication.
The primary clinical toxicity of ribavirin is hemolytic anemia. The anemia associated with ribavirin therapy may result in worsening of cardiac disease and lead to fatal and nonfatal myocardial infarctions. Patients with a history of significant or unstable cardiac disease should not be treated with ribavirin [see WARNINGS AND PRECAUTIONS (5.2), ADVERSE REACTIONS (6.1), and DOSAGE AND ADMINISTRATION (2.3)].
Significant teratogenic and/or embryocidal effects have been demonstrated in all animal species exposed to ribavirin. In addition, ribavirin has a multiple dose half-life of 12 days, and it may persist in non-plasma compartments for as long as 6 months. Therefore, ribavirin, including ribavirin, is contraindicated in women who are pregnant and in the male partners of women who are pregnant. Extreme care must be taken to avoid pregnancy during therapy and for 6 months after completion of therapy in both female patients and in female partners of male patients who are taking ribavirin therapy. At least two reliable forms of effective contraception must be utilized during treatment and during the 6month post treatment follow-up period [see CONTRAINDICATIONS (4), WARNINGS AND PRECAUTIONS (5.1), and USE IN SPECIFIC POPULATIONS (8.1)].
1. INDICATIONS AND USAGE
Ribavirin in combination with peginterferon alfa-2a is indicated for the treatment of adults with chronic hepatitis C (CHC) virus infection who have compensated liver disease and have not been previously treated with interferon alpha.
The following points should be considered when initiating ribavirin combination therapy with peginterferon alfa-2a:
2. DOSAGE AND ADMINISTRATION
2.1 Chronic Hepatitis C Monoinfection
The daily dose of ribavirin is 800 mg to 1200 mg administered orally in two divided doses. The dose should be individualized to the patient depending on baseline disease characteristics (e.g., genotype), response to therapy, and tolerability of the regimen (see Table 1).
Ribavirin should be taken with food.
2.2 Chronic Hepatitis C with HIV Coinfection
The recommended dose for treatment of chronic hepatitis C in patients coinfected with HIV is peginterferon alfa-2a 180 mcg subcutaneous once weekly and ribavirin 800 mg by mouth daily for a total duration of 48 weeks, regardless of HCV genotype.
Ribavirin should be taken with food.
2.3 Dose Modifications
If severe adverse reactions or laboratory abnormalities develop during combination ribavirin/peginterferon alfa-2a therapy, the dose should be modified or discontinued, if appropriate, until the adverse reactions abate or decrease in severity. If intolerance persists after dose adjustment, ribavirin/peginterferon alfa-2a therapy should be discontinued. Table 2 provides guidelines for dose modifications and discontinuation based on the patient’s hemoglobin concentration and cardiac status.
Ribavirin should be administered with caution to patients with pre-existing cardiac disease. Patients should be assessed before commencement of therapy and should be appropriately monitored during therapy. If there is any deterioration of cardiovascular status, therapy should be stopped [see WARNINGS AND PRECAUTIONS (5.2)].
Once ribavirin has been withheld due to either a laboratory abnormality or clinical manifestation, an attempt may be made to restart ribavirin at 600 mg daily and further increase the dose to 800 mg daily. However, it is not recommended that ribavirin be increased to the original assigned dose (1000 mg to 1200 mg).
See peginterferon alfa-2a full prescribing information for recommendations on peginterferon alfa-2a dose modification.
2.4 Discontinuation of Dosing
Discontinuation of peginterferon alfa-2a/ ribavirin therapy should be considered if the patient has failed to demonstrate at least a 2 log10 reduction from baseline in HCV RNA by 12 weeks of therapy, or undetectable HCV RNA levels after 24 weeks of therapy.
Peginterferon alfa-2a/ ribavirin therapy should be discontinued in patients who develop hepatic decompensation during treatment [see WARNINGS AND PRECAUTIONS (5.3)].
2.5 Renal Impairment
Ribavirin should not be used in patients with creatinine clearance < 50 mL/min [see USE IN SPECIFIC POPULATIONS (8.7)].
3. DOSAGE FORMS AND STRENGTHS
200 mg - light pink to pink, round, biconvex, beveled, film-coated tablets;
400 mg - light pink to pink, capsule shaped, biconvex, film-coated tablets;
500 mg - light pink to pink, modified capsule shaped, biconvex, film-coated tablets;
600 mg - light pink to pink, modified capsule shaped, biconvex, film-coated tablets
5. WARNINGS AND PRECAUTIONS
Significant adverse reactions associated with ribavirin/peginterferon alfa-2a combination therapy include severe depression and suicidal ideation, hemolytic anemia, suppression of bone marrow function, autoimmune and infectious disorders, ophthalmologic disorders, cerebrovascular disorders, pulmonary dysfunction, colitis, pancreatitis, and diabetes.
The Peginterferon alfa-2a Package Insert should be reviewed in its entirety for additional safety information prior to initiation of combination treatment.
Ribavirin may cause birth defects and/or death of the exposed fetus. Ribavirin has demonstrated significant teratogenic and/or embryocidal effects in all animal species in which adequate studies have been conducted. These effects occurred at doses as low as one twentieth of the recommended human dose of ribavirin.
Ribavirin therapy should not be started unless a report of a negative pregnancy test has been obtained immediately prior to planned initiation of therapy. Extreme care must be taken to avoid pregnancy in female patients and in female partners of male patients. Patients should be instructed to use at least two forms of effective contraception during treatment and for 6 months after treatment has been stopped. Pregnancy testing should occur monthly during ribavirin therapy and for 6 months after therapy has stopped [see BOXED WARNING, CONTRAINDICATIONS (4), USE IN SPECIFIC POPULATIONS (8.1), and PATIENT COUNSELING INFORMATION (17)].
The primary toxicity of ribavirin is hemolytic anemia, which was observed in approximately 13% of all ribavirin/peginterferon alfa-2a- treated subjects in clinical trials. Anemia associated with ribavirin occurs within 1 to 2 weeks of initiation of therapy. Because the initial drop in hemoglobin may be significant, it is advised that hemoglobin or hematocrit be obtained pretreatment and at week 2 and week 4 of therapy or more frequently if clinically indicated. Patients should then be followed as clinically appropriate. Caution should be exercised in initiating treatment in any patient with baseline risk of severe anemia (e.g., spherocytosis, history of gastrointestinal bleeding) [see DOSAGE AND ADMINISTRATION (2.3)].
Fatal and nonfatal myocardial infarctions have been reported in patients with anemia caused by ribavirin. Patients should be assessed for underlying cardiac disease before initiation of ribavirin therapy. Patients with pre-existing cardiac disease should have electrocardiograms administered before treatment, and should be appropriately monitored during therapy. If there is any deterioration of cardiovascular status, therapy should be suspended or discontinued [see DOSAGE AND ADMINISTRATION (2.3)]. Because cardiac disease may be worsened by drug-induced anemia, patients with a history of significant or unstable cardiac disease should not use ribavirin [see BOXED WARNING, and DOSAGE AND ADMINISTRATION (2.3)].
5.3 Hepatic Failure
Chronic hepatitis C (CHC) patients with cirrhosis may be at risk of hepatic decompensation and death when treated with alpha interferons, including peginterferon alfa-2a. Cirrhotic CHC patients coinfected with HIV receiving highly active antiretroviral therapy (HAART) and interferon alfa-2a with or without ribavirin appear to be at increased risk for the development of hepatic decompensation compared to patients not receiving HAART. In Study NR15961 [see CLINICAL STUDIES (14.3)], among 129 CHC/HIV cirrhotic patients receiving HAART, 14 (11%) of these patients across all treatment arms developed hepatic decompensation resulting in 6 deaths. All 14 patients were on NRTIs, including stavudine, didanosine, abacavir, zidovudine, and lamivudine. These small numbers of patients do not permit discrimination between specific NRTIs or the associated risk. During treatment, patients’ clinical status and hepatic function should be closely monitored for signs and symptoms of hepatic decompensation. Treatment with peginterferon alfa-2a/ ribavirin should be discontinued immediately in patients with hepatic decompensation [see CONTRAINDICATIONS (4)]
Severe acute hypersensitivity reactions (e.g., urticaria, angioedema, bronchoconstriction, and anaphylaxis) have been observed during alpha interferon and ribavirin therapy. If such a reaction occurs, therapy with peginterferon alfa-2a and ribavirin should be discontinued immediately and appropriate medical therapy instituted. Serious skin reactions including vesiculobullous eruptions, reactions in the spectrum of Stevens-Johnson Syndrome (erythema multiforme major) with varying degrees of skin and mucosal involvement and exfoliative dermatitis (erythroderma) have been reported in patients receiving peginterferon alfa-2a with and without ribavirin. Patients developing signs or symptoms of severe skin reactions must discontinue therapy [see ADVERSE REACTIONS (6.2)].
5.5 Renal Impairment
Ribavirin should not be used in patients with creatinine clearance < 50 mL/min [see USE IN SPECIFIC POPULATIONS (8.7)].
5.6 Pulmonary Disorders
Dyspnea, pulmonary infiltrates, pneumonitis, pulmonary hypertension, and pneumonia have been reported during therapy with ribavirin and interferon. Occasional cases of fatal pneumonia have occurred. In addition, sarcoidosis or the exacerbation of sarcoidosis has been reported. If there is evidence of pulmonary infiltrates or pulmonary function impairment, patients should be closely monitored and, if appropriate, combination ribavirin/peginterferon alfa-2a treatment should be discontinued.
5.7 Bone Marrow Suppression
Pancytopenia (marked decreases in RBCs, neutrophils and platelets) and bone marrow suppression have been reported in the literature to occur within 3 to 7 weeks after the concomitant administration of pegylated interferon/ribavirin and azathioprine. In this limited number of patients (n=8), myelotoxicity was reversible within 4 to 6 weeks upon withdrawal of both HCV antiviral therapy and concomitant azathioprine and did not recur upon reintroduction of either treatment alone. Peginterferon alfa-2a, ribavirin, and azathioprine should be discontinued for pancytopenia, and pegylated interferon/ribavirin should not be re-introduced with concomitant azathioprine [see DRUG INTERACTIONS (7.3)].
5.9 Laboratory Tests
Before beginning peginterferon alfa-2a/ ribavirin combination therapy, standard hematological and biochemical laboratory tests are recommended for all patients. Pregnancy screening for women of childbearing potential must be performed. Patients who have pre-existing cardiac abnormalities should have electrocardiograms administered before treatment with peginterferon alfa-2a/ ribavirin.
After initiation of therapy, hematological tests should be performed at 2 weeks and 4 weeks and biochemical tests should be performed at 4 weeks. Additional testing should be performed periodically during therapy. In the clinical studies, the CBC (including hemoglobin level and white blood cell and platelet counts) and chemistries (including liver function tests and uric acid) were measured at 1, 2, 4, 6, and 8 weeks, and then every 4 to 6 weeks or more frequently if abnormalities were found. Thyroid stimulating hormone (TSH) was measured every 12 weeks. Monthly pregnancy testing should be performed during combination therapy and for 6 months after discontinuing therapy.
The entrance criteria used for the clinical studies of ribavirin and peginterferon alfa-2a may be considered as a guideline to acceptable baseline values for initiation of treatment:
6. ADVERSE REACTIONS
Peginterferon alfa-2a in combination with ribavirin causes a broad variety of serious adverse reactions [see BOXED WARNINGand WARNINGS AND PRECAUTIONS (5)]. The most common serious or life-threatening adverse reactions induced or aggravated by ribavirin/peginterferon alfa-2a include depression, suicide, relapse of drug abuse/overdose, and bacterial infections each occurring at a frequency of < 1%. Hepatic decompensation occurred in 2% (10/574 CHC/HIV patients [see WARNINGS AND PRECAUTIONS (5.3)].
6.1 Clinical Studies Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.
In the pivotal registration trials NV15801 and NV15942, 886 patients received ribavirin for 48 weeks at doses of 1000/1200 mg based on body weight. In these trials, one or more serious adverse reactions occurred in 10% of CHC monoinfected subjects and in 19% of CHC/HIV subjects receiving peginterferon alfa-2a alone or in combination with ribavirin. The most common serious adverse event (3% in CHC and 5% in CHC/HIV) was bacterial infection (e.g., sepsis, osteomyelitis, endocarditis, pyelonephritis, pneumonia).
Other serious adverse reactions occurred at a frequency of < 1% and included: suicide, suicidal ideation, psychosis, aggression, anxiety, drug abuse and drug overdose, angina, hepatic dysfunction, fatty liver, cholangitis, arrhythmia, diabetes mellitus, autoimmune phenomena (e.g., hyperthyroidism, hypothyroidism, sarcoidosis, systemic lupus erythematosus, rheumatoid arthritis), peripheral neuropathy, aplastic anemia, peptic ulcer, gastrointestinal bleeding, pancreatitis, colitis, corneal ulcer, pulmonary embolism, coma, myositis, cerebral hemorrhage, thrombotic thrombocytopenic purpura, psychotic disorder, and hallucination.
The percentage of patients in clinical trials who experienced one or more adverse events was 98%. The most commonly reported adverse reactions were psychiatric reactions, including depression, insomnia, irritability, anxiety, and flu-like symptoms such as fatigue, pyrexia, myalgia, headache and rigors. Other common reactions were anorexia, nausea and vomiting, diarrhea, arthralgias, injection site reactions, alopecia, and pruritus. Table 3 shows rates of adverse events occurring in ≥ 5% subjects receiving pegylated interferon and ribavirin combination therapy in the CHC Clinical Trial, NV15801.
Ten percent of CHC monoinfected patients receiving 48 weeks of therapy with peginterferon alfa-2a in combination with ribavirin discontinued therapy; 16% of CHC/HIV coinfected patients discontinued therapy. The most common reasons for discontinuation of therapy were psychiatric, flu-like syndrome (e.g., lethargy, fatigue, headache), dermatologic and gastrointestinal disorders and laboratory abnormalities (thrombocytopenia, neutropenia, and anemia).
Overall 39% of patients with CHC or CHC/HIV required modification of peginterferon alfa-2a and/or ribavirin therapy. The most common reason for dose modification of peginterferon alfa-2a in CHC and CHC/HIV patients was for laboratory abnormalities; neutropenia (20% and 27%, respectively) and thrombocytopenia (4% and 6%, respectively). The most common reason for dose modification of ribavirin in CHC and CHC/HIV patients was anemia (22% and 16%, respectively).
Peginterferon alfa-2a dose was reduced in 12% of patients receiving 1000 mg to 1200 mg ribavirin for 48 weeks and in 7% of patients receiving 800 mg ribavirin for 24 weeks. Ribavirin dose was reduced in 21% of patients receiving 1000 mg to 1200 mg ribavirin for 48 weeks and in 12% of patients receiving 800 mg ribavirin for 24 weeks.
Chronic hepatitis C monoinfected patients treated for 24 weeks with peginterferon alfa-2a and 800 mg ribavirin were observed to have lower incidence of serious adverse events (3% vs. 10%), hemoglobin < 10g/dL (3% vs. 15%), dose modification of peginterferon alfa-2a (30% vs. 36%) and ribavirin (19% vs. 38%), and of withdrawal from treatment (5% vs. 15%) compared to patients treated for 48 weeks with peginterferon alfa-2a and 1000 mg or 1200 mg ribavirin. On the other hand, the overall incidence of adverse events appeared to be similar in the two treatment groups.
The adverse event profile of coinfected patients treated with peginterferon alfa-2a/ribavirin in Study NR15961 was generally similar to that shown for monoinfected patients in Study NV15801 (Table 3). Events occurring more frequently in coinfected patients were neutropenia (40%), anemia (14%), thrombocytopenia (8%), weight decrease (16%), and mood alteration (9%).
Laboratory Test Abnormalities
Anemia due to hemolysis is the most significant toxicity of ribavirin therapy. Anemia (hemoglobin < 10 g/dL) was observed in 13% of all ribavirin and peginterferon alfa-2a combination-treated patients in clinical trials. The maximum drop in hemoglobin occurred during the first 8 weeks of initiation of ribavirin therapy [see DOSAGE AND ADMINISTRATION (2.3)].
6.2 Postmarketing Experience
The following adverse reactions have been identified and reported during post-approval use of peginterferon alfa-2a/ribavirin combination therapy. 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.
Blood and Lymphatic System disorders
Pure red cell aplasia
Ear and Labyrinth disorders
Hearing impairment, hearing loss
Serous retinal detachment
Liver and renal graft rejection
Metabolism and Nutrition disorders
Skin and Subcutaneous Tissue disorders
Stevens-Johnson Syndrome (SJS)
Toxic epidermal necrolysis (TEN)
7. DRUG INTERACTIONS
7.1 Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
In vitro data indicate ribavirin reduces phosphorylation of lamivudine, stavudine, and zidovudine. However, no pharmacokinetic (e.g., plasma concentrations or intracellular triphosphorylated active metabolite concentrations) or pharmacodynamic (e.g., loss of HIV/HCV virologic suppression) interaction was observed when ribavirin and lamivudine (n=18), stavudine (n=10), or zidovudine (n=6) were co-administered as part of a multi-drug regimen to HCV/HIV coinfected patients.
In Study NR15961 among the CHC/HIV coinfected cirrhotic patients receiving NRTIs cases of hepatic decompensation (some fatal) were observed [see WARNINGS AND PRECAUTIONS (5.3)].
Patients receiving peginterferon alfa-2a/ribavirin and NRTIs should be closely monitored for treatment associated toxicities. Physicians should refer to prescribing information for the respective NRTIs for guidance regarding toxicity management. In addition, dose reduction or discontinuation of peginterferon alfa-2a, ribavirin or both should also be considered if worsening toxicities are observed, including hepatic decompensation (e.g., Child-Pugh ≥ 6) [see WARNINGS AND PRECAUTIONS (5.3) and DOSAGE AND ADMINISTRATION (2.3)].
Co-administration of ribavirin and didanosine is contraindicated. Didanosine or its active metabolite (dideoxyadenosine 5’-triphosphate) concentrations are increased when didanosine is co-administered with ribavirin, which could cause or worsen clinical toxicities. Reports of fatal hepatic failure, as well as peripheral neuropathy, pancreatitis, and symptomatic hyperlactatemia/lactic acidosis have been reported in clinical trials [see CONTRAINDICATIONS (4)].
In Study NR15961, patients who were administered zidovudine in combination with peginterferon alfa-2a/ribavirin developed severe neutropenia (ANC < 500) and severe anemia (hemoglobin < 8 g/dL) more frequently than similar patients not receiving zidovudine (neutropenia 15% vs. 9%) (anemia 5% vs. 1%). Discontinuation of zidovudine should be considered as medically appropriate.
7.2 Drugs Metabolized by Cytochrome P450
The use of ribavirin to treat chronic hepatitis C in patients receiving azathioprine has been reported to induce severe pancytopenia and may increase the risk of azathioprine-related myelotoxicity. Inosine monophosphate dehydrogenase (IMDH) is required for one of the metabolic pathways of azathioprine. Ribavirin is known to inhibit IMDH, thereby leading to accumulation of an azathioprine metabolite, 6-methylthioinosine monophosphate (6-MTITP), which is associated with myelotoxicity (neutropenia, thrombocytopenia, and anemia). Patients receiving azathioprine with ribavirin should have complete blood counts, including platelet counts, monitored weekly for the first month, twice monthly for the second and third months of treatment, then monthly or more frequently if dosage or other therapy changes are necessary [see WARNINGS AND PRECAUTIONS (5.7)].
8. USE IN SPECIFIC POPULATIONS
Pregnancy: Category X [see CONTRAINDICATIONS (4)].
Ribavirin produced significant embryocidal and/or teratogenic effects in all animal species in which adequate studies have been conducted. Malformations of the skull, palate, eye, jaw, limbs, skeleton, and gastrointestinal tract were noted. The incidence and severity of teratogenic effects increased with escalation of the drug dose. Survival of fetuses and offspring was reduced [see CONTRAINDICATIONS (4), WARNINGS AND PRECAUTIONS (5.1)].
In conventional embryotoxicity/teratogenicity studies in rats and rabbits, observed no-effect dose levels were well below those for proposed clinical use (0.3 mg/kg/day for both the rat and rabbit; approximately 0.06 times the recommended daily human dose of ribavirin). No maternal toxicity or effects on offspring were observed in a peri/postnatal toxicity study in rats dosed orally at up to 1 mg/kg/day (approximately 0.01 times the maximum recommended daily human dose of ribavirin).
Treatment and Post treatment: Potential Risk to the Fetus
Ribavirin is known to accumulate in intracellular components from where it is cleared very slowly. It is not known whether ribavirin is contained in sperm, and if so, will exert a potential teratogenic effect upon fertilization of the ova. However, because of the potential human teratogenic effects of ribavirin, male patients should be advised to take every precaution to avoid risk of pregnancy for their female partners.
Ribavirin should not be used by pregnant women or by men whose female partners are pregnant. Female patients of childbearing potential and male patients with female partners of childbearing potential should not receive ribavirin unless the patient and his/her partner are using effective contraception (two reliable forms) during therapy and for 6 months post therapy [see CONTRAINDICATIONS (4)].
Ribavirin Pregnancy Registry
A Ribavirin Pregnancy Registry has been established to monitor maternal-fetal outcomes of pregnancies of female patients and female partners of male patients exposed to ribavirin during treatment and for 6 months following cessation of treatment. Healthcare providers and patients are encouraged to report such cases by calling 1-800-593-2214.
8.3 Nursing Mothers
It is not known whether ribavirin is excreted in human milk. Because many drugs are excreted in human milk and to avoid any potential for serious adverse reactions in nursing infants from ribavirin, a decision should be made either to discontinue nursing or therapy with ribavirin, based on the importance of the therapy to the mother.
8.4 Pediatric Use
Safety and effectiveness of ribavirin have not been established in patients below the age of 18.
8.5 Geriatric Use
Clinical studies of ribavirin and peginterferon alfa-2a did not include sufficient numbers of subjects aged 65 or over to determine whether they respond differently from younger subjects. Specific pharmacokinetic evaluations for ribavirin in the elderly have not been performed. The risk of toxic reactions to this drug may be greater in patients with impaired renal function. Ribavirin should not be administered to patients with creatinine clearance < 50 mL/min.
8.7 Renal Impairment
The pharmacokinetics of ribavirin following administration of ribavirin have not been studied in patients with renal impairment and there are limited data from clinical trials on administration of ribavirin in patients with creatinine clearance < 50 mL/min. Therefore, patients with creatinine clearance < 50 mL/min should not be treated with ribavirin [see WARNINGS AND PRECAUTIONS (5.5) and DOSAGE AND ADMINISTRATION (2.5)].
8.8 Hepatic Impairment
The effect of hepatic impairment on the pharmacokinetics of ribavirin following administration of ribavirin has not been evaluated. The clinical trials of ribavirin were restricted to patients with Child-Pugh class A disease.
Ribavirin pharmacokinetics, when corrected for weight, are similar in male and female patients.
8.10 Organ Transplant Recipients
The safety and efficacy of peginterferon alfa-2a and ribavirin treatment have not been established in patients with liver and other transplantations. As with other alpha interferons, liver and renal graft rejections have been reported on peginterferon alfa-2a, alone or in combination with ribavirin [see ADVERSE REACTIONS (6.2)].
No cases of overdose with ribavirin have been reported in clinical trials. Hypocalcemia and hypomagnesemia have been observed in persons administered greater than the recommended dosage of ribavirin. In most of these cases, ribavirin was administered intravenously at dosages up to and in some cases exceeding four times the recommended maximum oral daily dose.
Each film-coated ribavirin tablet intended for oral administration contains 200 mg or 400 mg or 500 mg or 600 mg of ribavirin. In addition, each tablet contains the following inactive ingredients: crospovidone, hypromellose, iron oxide red, iron oxide yellow, magnesium stearate, microcrystalline cellulose, polyethylene glycol, povidone, silicon dioxide, talc and titanium dioxide.
12. CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
Ribavirin is an antiviral drug [see CLINICAL PHARMACOLOGY (12.4)].
Multiple dose ribavirin pharmacokinetic data are available for HCV patients who received ribavirin in combination with peginterferon alfa-2a. Following administration of 1200 mg/day with food for 12 weeks mean±SD (n=39; body weight > 75 kg) AUC0-12hr was 25,361±7110 ng·hr/mL and Cmax was 2748±818 ng/mL. The average time to reach Cmax was 2 hours. Trough ribavirin plasma concentrations following 12 weeks of dosing with food were 1662±545 ng/mL in HCV infected patients who received 800 mg/day (n=89), and 2112±810 ng/mL in patients who received 1200 mg/day (n=75; body weight > 75 kg).
The terminal half-life of ribavirin following administration of a single oral dose of ribavirin is about 120 to 170 hours. The total apparent clearance following administration of a single oral dose of ribavirin is about 26 L/h. There is extensive accumulation of ribavirin after multiple dosing (twice daily) such that the Cmax at steady state was four-fold higher than that of a single dose.
Effect of Food on Absorption of Ribavirin
Bioavailability of a single oral dose of ribavirin was increased by co-administration with a high-fat meal. The absorption was slowed (Tmax was doubled) and the AUC0-192h and Cmax increased by 42% and 66%, respectively, when ribavirin was taken with a high-fat meal compared with fasting conditions [see DOSAGE AND ADMINISTRATION (2.1) and PATIENT COUNSELING INFORMATION (17)].
Elimination and Metabolism
The contribution of renal and hepatic pathways to ribavirin elimination after administration of ribavirin is not known. In vitro studies indicate that ribavirin is not a substrate of CYP450 enzymes.
The mechanism by which ribavirin contributes to its antiviral efficacy in the clinic is not fully understood. Ribavirin has direct antiviral activity in tissue culture against many RNA viruses. Ribavirin increases the mutation frequency in the genomes of several RNA viruses and ribavirin triphosphate inhibits HCV polymerase in a biochemical reaction.
Antiviral Activity in Cell Culture
In the stable HCV cell culture model system (HCV replicon), ribavirin inhibited autonomous HCV RNA replication with a 50% effective concentration (EC50) value of 11 to 21 mcM. In the same model, PEG-IFN α-2a also inhibited HCV RNA replication, with an EC50 value of 0.1 to 3 ng/mL. The combination of PEG-IFN α-2a and ribavirin was more effective at inhibiting HCV RNA replication than either agent alone.
Different HCV genotypes display considerable clinical variability in their response to PEG-IFN-α and ribavirin therapy. Viral genetic determinants associated with the variable response have not been definitively identified.
Cross-resistance between IFN α and ribavirin has not been observed.
13. NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairment Of Fertility
In a p53 (+/-) mouse carcinogenicity study up to the maximum tolerated dose of 100 mg/kg/day, ribavirin was not oncogenic. Ribavirin was also not oncogenic in a rat 2 year carcinogenicity study at doses up to the maximum tolerated dose of 60 mg/kg/day. On a body surface area basis, these doses are approximately 0.5 and 0.6 times the maximum recommended daily human dose of ribavirin, respectively.
Ribavirin demonstrated mutagenic activity in the in vitro mouse lymphoma assay. No clastogenic activity was observed in an in vivo mouse micronucleus assay at doses up to 2000 mg/kg. However, results from studies published in the literature show clastogenic activity in the in vivo mouse micronucleus assay at oral doses up to 2000 mg/kg. A dominant lethal assay in rats was negative, indicating that if mutations occurred in rats they were not transmitted through male gametes. However, potential carcinogenic risk to humans cannot be excluded.
Impairment of Fertility
In a fertility study in rats, ribavirin showed a marginal reduction in sperm counts at the dose of 100 mg/kg/day with no effect on fertility. Upon cessation of treatment, total recovery occurred after 1 spermatogenesis cycle. Abnormalities in sperm were observed in studies in mice designed to evaluate the time course and reversibility of ribavirin-induced testicular degeneration at doses of 15 to 150 mg/kg/day (approximately 0.1 to 0.8 times the maximum recommended daily human dose of ribavirin) administered for 3 to 6 months. Upon cessation of treatment, essentially total recovery from ribavirin-induced testicular toxicity was apparent within 1 or 2 spermatogenic cycles.
Female patients of childbearing potential and male patients with female partners of childbearing potential should not receive ribavirin unless the patient and his/her partner are using effective contraception (two reliable forms). Based on a multiple dose half-life (t1/2) of ribavirin of 12 days, effective contraception must be utilized for 6 months post therapy (i.e., 15 half-lives of clearance for ribavirin).
No reproductive toxicology studies have been performed using peginterferon alfa-2a in combination with ribavirin. However, peginterferon alfa-2a and ribavirin when administered separately, each has adverse effects on reproduction. It should be assumed that the effects produced by either agent alone would also be caused by the combination of the two agents.
13.2 Animal Toxicology And/Or Pharmacology
Long-term studies in the mouse and rat (18 to 24 months; dose 20 to 75, and 10 to 40 mg/kg/day, respectively, approximately 0.1 to 0.4 times the maximum daily human dose of ribavirin) have demonstrated a relationship between chronic ribavirin exposure and an increased incidence of vascular lesions (microscopic hemorrhages) in mice. In rats, retinal degeneration occurred in controls, but the incidence was increased in ribavirin-treated rats.
14. CLINICAL STUDIES
14.1 Chronic Hepatitis C Patients
The safety and effectiveness of peginterferon alfa-2a in combination with ribavirin for the treatment of hepatitis C virus infection were assessed in two randomized controlled clinical trials. All patients were adults, had compensated liver disease, detectable hepatitis C virus, liver biopsy diagnosis of chronic hepatitis, and were previously untreated with interferon. Approximately 20% of patients in both studies had compensated cirrhosis (Child-Pugh class A). Patients coinfected with HIV were excluded from these studies.
In Study NV15801, patients were randomized to receive either peginterferon alfa-2a 180 mcg subcutaneous once weekly with an oral placebo, peginterferon alfa-2a 180 mcg once weekly with ribavirin 1000 mg by mouth (body weight < 75 kg) or 1200 mg by mouth (body weight ≥ 75 kg) or interferon alfa-2b 3 MIU subcutaneous three times a week plus ribavirin 1000 mg or 1200 mg by mouth. All patients received 48 weeks of therapy followed by 24 weeks of treatment-free follow-up. Ribavirin or placebo treatment assignment was blinded. Sustained virological response was defined as undetectable (< 50 IU/mL) HCV RNA on or after study week 68. Peginterferon alfa-2a in combination with ribavirin resulted in a higher SVR compared to peginterferon alfa-2a alone or interferon alfa-2b and ribavirin (Table 5). In all treatment arms, patients with viral genotype 1, regardless of viral load, had a lower response rate to peginterferon alfa-2a in combination with ribavirin compared to patients with other viral genotypes.
In Study NV15942, all patients received peginterferon alfa-2a 180 mcg subcutaneous once weekly and were randomized to treatment for either 24 or 48 weeks and to a ribavirin dose of either 800 mg or 1000 mg/1200 mg (for body weight < 75 kg/≥ 75 kg). Assignment to the four treatment arms was stratified by viral genotype and baseline HCV viral titer. Patients with genotype 1 and high viral titer (defined as > 2 x 106 HCV RNA copies/mL serum) were preferentially assigned to treatment for 48 weeks.
Sustained Virologic Response (SVR) and HCV Genotype
HCV 1 and 4- Irrespective of baseline viral titer, treatment for 48 weeks with peginterferon alfa-2a and 1000 mg or 1200 mg of ribavirin resulted in higher SVR (defined as undetectable HCV RNA at the end of the 24 week treatment-free follow-up period) compared to shorter treatment (24 weeks) and/or 800 mg ribavirin.
HCV 2 and 3- Irrespective of baseline viral titer, treatment for 24 weeks with peginterferon alfa-2a and 800 mg of ribavirin resulted in a similar SVR compared to longer treatment (48 weeks) and/or 1000 mg or 1200 mg of ribavirin (see Table 6).
The numbers of patients with genotype 5 and 6 were too few to allow for meaningful assessment.
14.2 Other Treatment Response Predictors
Treatment response rates are lower in patients with poor prognostic factors receiving pegylated interferon alpha therapy. In studies NV15801 and NV15942, treatment response rates were lower in patients older than 40 years (50% vs. 66%), in patients with cirrhosis (47% vs. 59%), in patients weighing over 85 kg (49% vs. 60%), and in patients with genotype 1 with high vs. low viral load (43% vs. 56%). African-American patients had lower response rates compared to Caucasians.
In studies NV15801 and NV15942, lack of early virologic response by 12 weeks (defined as HCV RNA undetectable or > 2 log10 lower than baseline) was grounds for discontinuation of treatment. Of patients who lacked an early viral response by 12 weeks and completed a recommended course of therapy despite a protocol-defined option to discontinue therapy, 5/39 (13%) achieved an SVR. Of patients who lacked an early viral response by 24 weeks, 19 completed a full course of therapy and none achieved an SVR.
14.3 Chronic Hepatitis C/HIV Coinfected Patients
In Study NR15961, patients with CHC/HIV were randomized to receive either peginterferon alfa-2a 180 mcg subcutaneous once weekly plus an oral placebo, peginterferon alfa-2a 180 mcg once weekly plus ribavirin 800 mg by mouth daily or interferon alfa-2a, 3 MIU subcutaneous three times a week plus ribavirin 800 mg by mouth daily. All patients received 48 weeks of therapy and sustained virologic response (SVR) was assessed at 24 weeks of treatment-free follow-up. Ribavirin or placebo treatment assignment was blinded in the peginterferon alfa-2a treatment arms. All patients were adults, had compensated liver disease, detectable hepatitis C virus, liver biopsy diagnosis of chronic hepatitis C, and were previously untreated with interferon. Patients also had CD4+ cell count ≥ 200 cells/mcL or CD4+ cell count ≥ 100 cells/mcL but < 200 cells/mcL and HIV-1 RNA < 5000 copies/mL, and stable status of HIV. Approximately 15% of patients in the study had cirrhosis. Results are shown in Table 7.
Of the patients who did not demonstrate either undetectable HCV RNA or at least a 2 log10 reduction from baseline in HCV RNA titer by 12 weeks of peginterferon alfa-2a and ribavirin combination therapy, 2% (2/85) achieved an SVR.
In CHC patients with HIV coinfection who received 48 weeks of peginterferon alfa-2a alone or in combination with ribavirin treatment, mean and median HIV RNA titers did not increase above baseline during treatment or 24 weeks post treatment.
16. HOW SUPPLIED/STORAGE AND HANDLING
NDC 65841-046-03 in bottle of 168 tablets
NDC 65841-046-28 in bottle of 180 tablets
NDC 65841-046-10 in bottle of 1000 tablets
NDC 65841-046-30 in blister pack of 100 unit dose tablets
Ribavirin Tablets, 400 mg are light pink to pink, capsule shaped, biconvex, film-coated tablets debossed with ‘ZD’ and ‘07’ on one side and plain on other side and supplied as follows:
NDC 65841-603-17 in bottle of 28 tablets
NDC 65841-603-07 in bottle of 56 tablets
NDC 65841-603-14 in bottle of 60 tablets
Ribavirin Tablets, 500 mg are light pink to pink, modified capsule shaped, biconvex, film-coated tablets debossed with ‘ZC56’ on one side and plain on the other side and supplied as follows:
NDC 65841-632-17 in bottle of 28 tablets
NDC 65841-632-07 in bottle of 56 tablets
NDC 65841-632-14 in bottle of 60 tablets
Ribavirin Tablets, 600 mg are light pink to pink, modified capsule shaped, biconvex, film-coated tablets debossed with ‘ZD’ and ‘08’ on one side and plain on other side and supplied as follows:
NDC 65841-129-17 in bottle of 28 tablets
NDC 65841-129-07 in bottle of 56 tablets
NDC 65841-129-14 in bottle of 60 tablets
Storage and Handling
Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature].
Keep bottle tightly closed.
17. PATIENT COUNSELING INFORMATION
Patients must be informed that ribavirin may cause birth defects and/or death of the exposed fetus. Ribavirin therapy must not be used by women who are pregnant or by men whose female partners are pregnant. Extreme care must be taken to avoid pregnancy in female patients and in female partners of male patients taking ribavirin therapy and for 6 months post therapy. Ribavirin therapy should not be initiated until a report of a negative pregnancy test has been obtained immediately prior to initiation of therapy. Patients must perform a pregnancy test monthly during therapy and for 6 months post therapy.
Female patients of childbearing potential and male patients with female partners of childbearing potential must be advised of the teratogenic/embryocidal risks and must be instructed to practice effective contraception during ribavirin therapy and for 6 months post therapy. Patients should be advised to notify the healthcare provider immediately in the event of a pregnancy [see CONTRAINDICATIONS (4) and WARNINGS AND PRECAUTIONS (5.1)].
The most common adverse event associated with ribavirin is anemia, which may be severe [see BOXED WARNING, WARNINGS AND PRECAUTIONS (5.2) and ADVERSE REACTIONS (6.1)]. Patients should be advised that laboratory evaluations are required prior to starting ribavirin therapy and periodically thereafter [see WARNINGS AND PRECAUTIONS (5.9)]. It is advised that patients be well hydrated, especially during the initial stages of treatment.
Patients who develop dizziness, confusion, somnolence, and fatigue should be cautioned to avoid driving or operating machinery.
Patients should be advised to take ribavirin with food.
Patients should be questioned about prior history of drug abuse before initiating ribavirin/peginterferon alfa-2a, as relapse of drug addiction and drug overdoses have been reported in patients treated with interferons.
Patients should be advised not to drink alcohol, as alcohol may exacerbate chronic hepatitis C infection.
Patient should be informed about what to do in the event they miss a dose of ribavirin. The missed doses should be taken as soon as possible during the same day. Patients should not double the next dose. Patients should be advised to call their healthcare provider if they have questions.
Patients should be informed that the effect of peginterferon alfa-2a/ribavirin treatment of hepatitis C infection on transmission is not known, and that appropriate precautions to prevent transmission of hepatitis C virus should be taken.
Patients should be informed regarding the potential benefits and risks attendant to the use of ribavirin. Instructions on appropriate use should be given, including review of the contents of the enclosed MEDICATION GUIDE, which is not a disclosure of all or possible adverse effects.
Read this Medication Guide carefully before you start taking ribavirin and read the Medication Guide each time you get more ribavirin. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or your treatment.
Also read the Medication Guide for peginterferon alfa-2a.
What is the most important information I should know about Ribavirin?
Ribavirin is a medicine used with another medicine called peginterferon alfa-2a to treat chronic (lasting a long time) hepatitis C infection in people whose liver still works normally, and who have not been treated before with a medicine called an interferon alpha. It is not known if ribavirin is safe and will work in children under 18 years of age.
Who should not take Ribavirin?
See "What is the most important information I should know about Ribavirin?"
Do not take ribavirin if you:
What should I tell my healthcare provider before taking Ribavirin?
Before you take ribavirin, tell your healthcare provider if you have or have had:
Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins and herbal supplements. Some medicines can cause serious side effects if taken while you also take ribavirin. Some medicines may affect how ribavirin works or ribavirin may affect how your other medicines work.
Especially tell your healthcare provider if you take any medicines to treat HIV, including didanosine (Videx or Videx EC), or if you take azathioprine (Imuran or Azasan).
Know the medicines you take. Keep a list of them to show your healthcare provider or pharmacist when you get a new medicine.
How should I take Ribavirin?
Ribavirin may cause serious side effects including:
See "What is the most important information I should know about Ribavirin?"
Common side effects of ribavirin taken with peginterferon alfa-2a include:
These are not all the possible side effects of ribavirin treatment. For more information, ask your healthcare provider or pharmacist.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Please address medical inquiries to, (MedicalAffairs@zydususa.com) Tel.: 1-877-993-8779.
How should I store Ribavirin?
General information about the safe and effective use of Ribavirin
It is not known if treatment with ribavirin can cure hepatitis C or if it can prevent liver damage (cirrhosis), liver failure or liver cancer that is caused by hepatitis C virus infections. It is not known if treatment with ribavirin will prevent an infected person from spreading the hepatitis C virus to another person.
Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use ribavirin for a condition for which it was not prescribed. Do not give ribavirin to other people, even if they have the same symptoms that you have. It may harm them.
This Medication Guide summarizes the most important information about ribavirin. If you would like more information, talk with your healthcare provider. You can ask your healthcare provider or pharmacist for information about ribavirin that is written for healthcare professionals.
What are the ingredients in Ribavirin Tablets?
Active Ingredient: ribavirin
Inactive Ingredients: crospovidone, hypromellose, iron oxide red, iron oxide yellow, magnesium stearate, microcrystalline cellulose, polyethylene glycol, povidone, silicon dioxide, talc and titanium dioxide.
This Medication Guide has been approved by the U.S. Food and Drug Administration.
PACKAGE LABEL.PRINCIPAL DISPLAY PANEL
Ribavirin Tablets , 200 mg
Ribavirin Tablets , 400 mg
Ribavirin Tablets , 500 mg
Ribavirin Tablets , 600 mg
Revised: 04/2011 Cadila Healthcare Limited
Reproduced with permission of U.S. National Library of Medicine
Copyright © 2018
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