Telbivudine warnings and precautions

# Warnings And Precautions

## Lactic Acidosis
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination with antiretrovirals. Female gender, obesity, and prolonged nucleoside exposure may be risk factors. Particular caution should be exercised when administering HBV nucleoside analogue reverse transcriptase inhibitors to patients with known risk factors for liver disease; however, cases have also been reported in patients with no known risk factors. Treatment with Tyzeka 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).

## Exacerbations of Hepatitis B after Discontinuation of Treatment
Severe acute exacerbations of hepatitis B have been reported in patients who have discontinued anti-hepatitis B therapy, including Tyzeka. 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, resumption of anti-hepatitis B therapy may be warranted .

## Myopathy
Cases of myopathy/myositis have been reported with Tyzeka use several weeks to months after starting therapy. Myopathy has also been reported with some other drugs in this class. Rhabdomyolysis has been reported during postmarketing use of Tyzeka .
Uncomplicated myalgia has been reported in Tyzeka-treated patients . Myopathy, defined as persistent unexplained muscle aches and/or muscle weakness in conjunction with increases in creatine kinase (CK) values, should be considered in any patient with diffuse myalgias, muscle tenderness, or muscle weakness. Among patients with Tyzeka-associated myopathy, no pattern with regard to the degree or timing of CK elevations has been observed. In addition, the predisposing factors for the development of myopathy among Tyzeka recipients are unknown. Patients should be advised to report promptly unexplained muscle aches, pain, tenderness, or weakness. Tyzeka therapy should be interrupted if myopathy is suspected, and discontinued if myopathy is confirmed. It is unknown whether the risk of myopathy during treatment with drugs in this class is increased with concurrent administration of other drugs associated with myopathy, including but not limited to: corticosteroids, chloroquine, hydroxychloroquine, certain HMG-CoA reductase inhibitors, fibric acid derivatives, penicillamine, zidovudine, cyclosporine, erythromycin, niacin, and certain azole antifungals. Physicians initiating concomitant treatment with any drug associated with myopathy should monitor patients closely for any signs or symptoms of unexplained muscle pain, tenderness, or weakness.

## Peripheral Neuropathy
Peripheral neuropathy has been reported with Tyzeka alone or in combination with pegylated interferon alfa-2a and other interferons. In one clinical trial, an increased risk and severity of peripheral neuropathy was observed with the combination use of Tyzeka 600mg daily and pegylated interferon alfa-2a 180 micrograms once weekly compared to Tyzeka or pegylated interferon alfa-2a alone . Such risk cannot be excluded for other dose regimens of pegylated interferon alfa-2a, or other alfa interferons (pegylated or standard). The safety and efficacy of Tyzeka in combination with pegylated interferons or other interferons for the treatment of chronic hepatitis B have not been demonstrated. Patients should be advised to report any numbness, tingling, and/or burning sensations in the arms and/or legs, with or without gait disturbance. Tyzeka therapy should be interrupted if peripheral neuropathy is suspected, and discontinued if peripheral neuropathy is confirmed .