telbivudine (Tyzeka)

Indications

• hepatitis B

Contraindications

Caution: patients > 65 years of age

Pregnancy category: B

Dosage

• 600 mg PO QD (taper, do NOT abruptly discontinue)

Tabs: 600 mg

Storage

• store in orginal container
  • oral solution must be used within two months once original container is opened

Dosage adjustment in renal failure

Table

Creatinine clearance	dosage
> 50 mL/min	600 mg QD
30-49 mL/min	600 mg every other day
< 30 mL/min	600 mg every 3 days
ESRD	600 mg every 4 days
dialysis	administer 600 mg after dialysis

Pharmacokinetics

• primarily cleared by renal excretion

Monitor

• serum ALT periodically & for several months after discontinuation

Adverse effects

• myalgia, myopathy may occurs weeks to months after starting therapy
• fatigue, malaise, pyrexia, arthralgia, abdominal pain, diarrhea, gastritis, cough, headache
• laboratory abnormalities
  • elevated serum creatine kinase, increased ALT, increased serum lipase, increased serum amylase, increased total bilirubin, neutropenia, thrombocytopenia
• fatal lactic acidosis may be complication

Drug interactions

• coadministration of telbivudine with drugs that alter renal function may alter plasma levels of telbivudine
• coadministration of other drugs associated with myopathy
  • corticosteroids, chloroquine, hydroxychloroquine, statins, fibrates, penicillamine, zidovudine, cyclsporine

• drug interaction(s) of antibiotics with warfarin

Mechanism of action

• thymine nucleoside analogue
• blocks hepatitis B DNA polymerase

Notes

cost $500/month

More general terms

• antiviral agent

Database

• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=159269