Tyzeka medication for Hepatitis B by Ray Sahelian, M.D.
Tyzeka (telbivudine) is used for the treatment of adults with chronic
hepatitis B (HBV),
a viral infection that attacks the liver and can cause lifelong
infection, scarring of the liver (cirrhosis), and eventually liver cancer, liver
failure, and death. Tyzeka is a new molecular entity, a medication containing an active substance that has never
before been approved for marketing in any form in the United States. T yzeka is
not a cure for hepatitis B, and long-term treatment benefits of this drug are
not known. Use of Tyzeka has not been shown to reduce the risk of transmission
of HBV to others through sexual contact or blood contamination.
Tyzeka Research
Tyzeka was studied in a year-long international clinical trial in 1,367 patients
with chronic HBV. Three-quarters of the trial participants were male, and all
were 16 years of age or older. The trial produced evidence of antiviral
effectiveness, including the suppression of hepatitis B virus, and improvement
in liver inflammation comparable to Epivir-HBV (lamivudine), one of five other
medications approved to treat patients with chronic HBV.
Tyzeka Side Effects
In clinical studies most common Tyzeka side effects were elevated CPK (creatinine phosphokinase, an enzyme that is present in muscle tissue and is
a marker for breakdown of muscle tissue), upper respiratory tract infection,
fatigue, headache, abdominal pain and cough. After several weeks to months of Tyzeka use, some patients developed
additional side effects ranging from transient muscle pain to muscle weakness. Those who
developed muscle weakness experienced significant improvement in their symptoms
when Tyzeka was discontinued. Muscle pain and damage from Tyzeka use appears to
be a common side effect.
Among drugs in the same class as Tyzeka, some cases of lactic acidosis (too much
acid in the body due to buildup of lactic acid) and severe enlargement and
accumulation of fat in the liver, including fatal cases, have been reported.
Stopping Tyzeka
Patients should stop Tyzeka after a discussion with their doctor.
As has happened with other forms of treatment for hepatitis B, some patients who
discontinued Tyzeka experienced a sudden and severe worsening of their hepatitis
B. Therefore, patients who discontinue Tyzeka should be closely monitored by
their doctor for at least several months.
Tyzeka is a
prescription medication manufactured by Novartis Pharma Stein AG, Stein, Switzerland and
marketed and distributed by Idenix Pharmaceuticals, Inc., Cambridge, MA.