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Epivir-HBV (Lamivudine) - Warnings and Precautions

 
 



WARNING

LACTIC ACIDOSIS AND SEVERE HEPATOMEGALY WITH STEATOSIS, INCLUDING FATAL CASES, HAVE BEEN REPORTED WITH THE USE OF NUCLEOSIDE ANALOGUES ALONE OR IN COMBINATION, INCLUDING LAMIVUDINE AND OTHER ANTIRETROVIRALS (SEE WARNINGS).

HUMAN IMMUNODEFICIENCY VIRUS (HIV) COUNSELING AND TESTING SHOULD BE OFFERED TO ALL PATIENTS BEFORE BEGINNING EPIVIR-HBV AND PERIODICALLY DURING TREATMENT (SEE WARNINGS), BECAUSE EPIVIR-HBV TABLETS AND ORAL SOLUTION CONTAIN A LOWER DOSE OF THE SAME ACTIVE INGREDIENT (LAMIVUDINE) AS EPIVIR ® TABLETS AND ORAL SOLUTION USED TO TREAT HIV INFECTION. IF TREATMENT WITH EPIVIR-HBV IS PRESCRIBED FOR CHRONIC HEPATITIS B FOR A PATIENT WITH UNRECOGNIZED OR UNTREATED HIV INFECTION, RAPID EMERGENCE OF HIV RESISTANCE IS LIKELY BECAUSE OF SUBTHERAPEUTIC DOSE AND INAPPROPRIATE MONOTHERAPY.

SEVERE ACUTE EXACERBATIONS OF HEPATITIS B HAVE BEEN REPORTED IN PATIENTS WHO HAVE DISCONTINUED ANTI-HEPATITIS B THERAPY (INCLUDING EPIVIR-HBV). HEPATIC FUNCTION SHOULD BE MONITORED CLOSELY WITH BOTH CLINICAL AND LABORATORY FOLLOW-UP FOR AT LEAST SEVERAL MONTHS IN PATIENTS WHO DISCONTINUE ANTI-HEPATITIS B THERAPY. IF APPROPRIATE, INITIATION OF ANTI-HEPATITIS B THERAPY MAY BE WARRANTED (SEE WARNINGS).

 

WARNINGS

Lactic Acidosis/Severe Hepatomegaly With Steatosis

Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination, including lamivudine and other antiretrovirals. A majority of these cases have been in women. Obesity and prolonged nucleoside exposure may be risk factors. Most of these reports have described patients receiving nucleoside analogues for treatment of HIV infection, but there have been reports of lactic acidosis in patients receiving lamivudine for hepatitis B. Particular caution should be exercised when administering EPIVIR or EPIVIR-HBV to any patient with known risk factors for liver disease; however, cases have also been reported in patients with no known risk factors. Treatment with EPIVIR or EPIVIR-HBV should be suspended in any patient who develops clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity (which may include hepatomegaly and steatosis even in the absence of marked transaminase elevations).

Important Differences Between Lamivudine-Containing Products, HIV Testing, and Risk of Emergence of Resistant HIV

EPIVIR-HBV Tablets and Oral Solution contain a lower dose of the same active ingredient (lamivudine) as EPIVIR Tablets and Oral Solution, COMBIVIR® (lamivudine/zidovudine) Tablets, and TRIZIVIR® (abacavir, lamivudine, and zidovudine) Tablets used to treat HIV infection. The formulation and dosage of lamivudine in EPIVIR-HBV are not appropriate for patients dually infected with HBV and HIV. If a decision is made to administer lamivudine to such patients, the higher dosage indicated for HIV therapy should be used as part of an appropriate combination regimen, and the prescribing information for EPIVIR, COMBIVIR, or TRIZIVIR as well as for EPIVIR-HBV should be consulted. HIV counseling and testing should be offered to all patients before beginning EPIVIR-HBV and periodically during treatment because of the risk of rapid emergence of resistant HIV and limitation of treatment options if EPIVIR-HBV is prescribed to treat chronic hepatitis B in a patient who has unrecognized or untreated HIV infection or acquires HIV infection during treatment.

Posttreatment Exacerbations of Hepatitis

Clinical and laboratory evidence of exacerbations of hepatitis have occurred after discontinuation of EPIVIR-HBV (these have been primarily detected by serum ALT elevations, in addition to the re-emergence of HBV DNA commonly observed after stopping treatment; see Table 7 for more information regarding frequency of posttreatment ALT elevations). Although most events appear to have been self-limited, fatalities have been reported in some cases. The causal relationship to discontinuation of lamivudine treatment is unknown. Patients should be closely monitored with both clinical and laboratory follow-up for at least several months after stopping treatment. There is insufficient evidence to determine whether re-initiation of therapy alters the course of posttreatment exacerbations of hepatitis.

Pancreatitis

Pancreatitis has been reported in patients receiving lamivudine, particularly in HIV-infected pediatric patients with prior nucleoside exposure.

PRECAUTIONS

General

Patients should be assessed before beginning treatment with EPIVIR-HBV by a physician experienced in the management of chronic hepatitis B.

Emergence of Resistance-Associated HBV Mutations

In controlled clinical trials, YMDD-mutant HBV were detected in patients with on-lamivudine re-appearance of HBV DNA after an initial decline below the solution-hybridization assay limit (see MICROBIOLOGY: Drug Resistance). These mutations can be detected by a research assay and have been associated with reduced susceptibility to lamivudine in vitro. Lamivudine-treated patients (adult and pediatric) with YMDD-mutant HBV at 52 weeks showed diminished treatment responses in comparison to lamivudine-treated patients without evidence of YMDD mutations, including lower rates of HBeAg seroconversion and HBeAg loss (no greater than placebo recipients), more frequent return of positive HBV DNA by solution-hybridization or branched-chain DNA assay, and more frequent ALT elevations. In the controlled trials, when patients developed YMDD-mutant HBV, they had a rise in HBV DNA and ALT from their own previous on-treatment levels. Progression of hepatitis B, including death, has been reported in some patients with YMDD-mutant HBV, including patients from the liver transplant setting and from other clinical trials. The long-term clinical significance of YMDD-mutant HBV is not known. Increased clinical and laboratory monitoring may aid in treatment decisions if emergence of viral mutants is suspected.

Limitations of Populations Studied

Safety and efficacy of EPIVIR-HBV have not been established in patients with decompensated liver disease or organ transplants; pediatric patients <2 years of age; patients dually infected with HBV and HCV, hepatitis delta, or HIV; or other populations not included in the principal phase III controlled studies. There are no studies in pregnant women and no data regarding effect on vertical transmission, and appropriate infant immunizations should be used to prevent neonatal acquisition of HBV.

Assessing Patients During Treatment

Patients should be monitored regularly during treatment by a physician experienced in the management of chronic hepatitis B. The safety and effectiveness of treatment with EPIVIR-HBV beyond 1 year have not been established. During treatment, combinations of such events such as return of persistently elevated ALT, increasing levels of HBV DNA over time after an initial decline below assay limit, progression of clinical signs or symptoms of hepatic disease, and/or worsening of hepatic necroinflammatory findings may be considered as potentially reflecting loss of therapeutic response. Such observations should be taken into consideration when determining the advisability of continuing therapy with EPIVIR-HBV.

The optimal duration of treatment, the durability of HBeAg seroconversions occurring during treatment, and the relationship between treatment response and long-term outcomes such as hepatocellular carcinoma or decompensated cirrhosis are not known.

Patients with Impaired Renal Function

Reduction of the dosage of EPIVIR-HBV is recommended for patients with impaired renal function (see CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION).

Information for Patients

A Patient Package Insert (PPI) for EPIVIR-HBV is available for patient information.

Patients should remain under the care of a physician while taking EPIVIR-HBV. They should discuss any new symptoms or concurrent medications with their physician.

Patients should be advised that EPIVIR-HBV is not a cure for hepatitis B, that the long-term treatment benefits of EPIVIR-HBV are unknown at this time, and, in particular, that the relationship of initial treatment response to outcomes such as hepatocellular carcinoma and decompensated cirrhosis is unknown. Patients should be informed that deterioration of liver disease has occurred in some cases when treatment was discontinued. Patients should be advised to discuss any changes in regimen with their physician.

Patients should be informed that emergence of resistant hepatitis B virus and worsening of disease can occur during treatment, and they should promptly report any new symptoms to their physician.

Patients should be counseled on the importance of testing for HIV to avoid inappropriate therapy and development of resistant HIV, and HIV counseling and testing should be offered before starting EPIVIR-HBV and periodically during therapy. Patients should be advised that EPIVIR-HBV Tablets and EPIVIR-HBV Oral Solution contain a lower dose of the same active ingredient (lamivudine) as EPIVIR Tablets, EPIVIR Oral Solution, COMBIVIR Tablets, and TRIZIVIR Tablets. EPIVIR-HBV should not be taken concurrently with EPIVIR, COMBIVIR, or TRIZIVIR (see WARNINGS). Patients infected with both HBV and HIV who are planning to change their HIV treatment regimen to a regimen that does not include EPIVIR, COMBIVIR, or TRIZIVIR should discuss continued therapy for hepatitis B with their physician.

Patients should be advised that treatment with EPIVIR-HBV has not been shown to reduce the risk of transmission of HBV to others through sexual contact or blood contamination (see Pregnancy section).

Diabetic patients should be advised that each 20-mL dose of EPIVIR-HBV Oral Solution contains 4 grams of sucrose.

Drug Interactions

Lamivudine is predominantly eliminated in the urine by active organic cationic secretion. The possibility of interactions with other drugs administered concurrently should be considered, particularly when their main route of elimination is active renal secretion via the organic cationic transport system (e.g., trimethoprim).

TMP 160 mg/SMX 800 mg once daily has been shown to increase lamivudine exposure (AUC) by 44% (see CLINICAL PHARMACOLOGY). No change in dose of either drug is recommended. There is no information regarding the effect on lamivudine pharmacokinetics of higher doses of TMP/SMX such as those used to treat Pneumocystis carinii pneumonia. No data are available regarding interactions with other drugs that have renal clearance mechanisms similar to that of lamivudine.

Lamivudine and zalcitabine may inhibit the intracellular phosphorylation of one another. Therefore, use of lamivudine in combination with zalcitabine is not recommended.

Carcinogenesis, Mutagenesis, and Impairment of Fertility

Lamivudine long-term carcinogenicity studies in mice and rats showed no evidence of carcinogenic potential at exposures up to 34 times (mice) and 200 times (rats) those observed in humans at the recommended therapeutic dose for chronic hepatitis B. Lamivudine was not active in a microbial mutagenicity screen or an in vitro cell transformation assay, but showed weak in vitro mutagenic activity in a cytogenetic assay using cultured human lymphocytes and in the mouse lymphoma assay. However, lamivudine showed no evidence of in vivo genotoxic activity in the rat at oral doses of up to 2,000 mg/kg producing plasma levels of 60 to 70 times those in humans at the recommended dose for chronic hepatitis B. In a study of reproductive performance, lamivudine administered to rats at doses up to 4,000 mg/kg/day, producing plasma levels 80 to 120 times those in humans, revealed no evidence of impaired fertility and no effect on the survival, growth, and development to weaning of the offspring.

Pregnancy

Pregnancy Category C. Reproduction studies have been performed in rats and rabbits at orally administered doses up to 4,000 mg/kg/day and 1,000 mg/kg/day, respectively, producing plasma levels up to approximately 60 times that for the adult HBV dose. No evidence of teratogenicity due to lamivudine was observed. Evidence of early embryolethality was seen in the rabbit at exposure levels similar to those observed in humans, but there was no indication of this effect in the rat at exposures up to 60 times that in humans. Studies in pregnant rats and rabbits showed that lamivudine is transferred to the fetus through the placenta. There are no adequate and well-controlled studies in pregnant women. Because animal reproductive toxicity studies are not always predictive of human response, lamivudine should be used during pregnancy only if the potential benefits outweigh the risks.

Lamivudine has not been shown to affect the transmission of HBV from mother to infant, and appropriate infant immunizations should be used to prevent neonatal acquisition of HBV.

Pregnancy Registry

To monitor maternal-fetal outcomes of pregnant women exposed to lamivudine, a Pregnancy Registry has been established. Physicians are encouraged to register patients by calling 1-800-258-4263.

Nursing Mothers

A study in lactating rats administered 45 mg/kg of lamivudine showed that lamivudine concentrations in milk were slightly greater than those in plasma. Lamivudine is also excreted in human milk. Samples of breast milk obtained from 20 mothers receiving lamivudine monotherapy (300 mg twice daily) or combination therapy (150 mg lamivudine twice daily and 300 mg zidovudine twice daily) had measurable concentrations of lamivudine.

Because of the potential for serious adverse reactions in nursing infants, mothers should be instructed not to breastfeed if they are receiving lamivudine.

Pediatric Use

HBV

Safety and efficacy of lamivudine for treatment of chronic hepatitis B in children have been studied in pediatric patients from 2 to 17 years of age in a controlled clinical trial (see CLINICAL PHARMACOLOGY, INDICATIONS AND USAGE, and DOSAGE AND ADMINISTRATION).

Safety and efficacy in pediatric patients <2 years of age have not been established.

HIV

See the complete prescribing information for EPIVIR Tablets and Oral Solution for additional information on pharmacokinetics of lamivudine in HIV-infected children.

Geriatric Use

Clinical studies of EPIVIR-HBV did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. In particular, because lamivudine is substantially excreted by the kidney and elderly patients are more likely to have decreased renal function, renal function should be monitored and dosage adjustments should be made accordingly (see PRECAUTIONS: Patients with Impaired Renal Function and DOSAGE AND ADMINISTRATION).

Page last updated: 2006-11-08

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