entecavir

entecavir,

an antiviral.

indication This drug is used to treat chronic hepatitis B.

contraindication Known hypersensitivity to this drug prohibits its use.

adverse effects Adverse effects of this drug include fatigue, dizziness, insomnia, nausea, vomiting, and diarrhea. Life-threatening side effects include lactic acidosis and severe hepatomegaly with stenosis. Common side effects include headache and dyspepsia.

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entecavir

Baraclude

Pharmacologic class: Guanosine nucleoside analogue

Therapeutic class: Antiviral

Pregnancy risk category C

FDA Boxed Warning

• Drug may cause lactic acidosis and severe hepatomegaly with steatosis (including fatal cases) when used alone or in combination with antiretrovirals.
• Severe acute hepatitis B exacerbations have occurred in patients who discontinued anti-hepatitis B therapy, including entecavir. Monitor hepatic function for at least several months after discontinuation. If appropriate, initiate anti-hepatitis B therapy.
• When used to treat chronic hepatitis B, drug may cause human immunodeficiency virus (HIV) resistance to HIV nucleoside reverse transcriptase inhibitors in patients with untreated HIV infection. Therapy isn't recommended for HIV/hepatitis B virus (HBV) co-infected patients except those also receiving highly active antiretroviral therapy.

Action

Competes with natural substrate deoxyguanosine triphosphate to inhibit HBV polymerase (reverse transcriptase)

Availability

Oral solution: 0.05 mg/ml

Tablets: 0.5 mg, 1 mg

⊘Indications and dosages

➣ Chronic HBV infection with evidence of active viral replication and either persistent serum transaminase elevations or histologically active disease

Adolescents and adults ages 16 and older: In patients who haven't received previous nucleosides, 0.5 mg P.O. daily 2 hours before or 2 hours after a meal. In patients with a history of hepatitis B viremia while receiving lamivudine or known lamivudine-resistant mutations, 1 mg P.O. daily 2 hours before or 2 hours after a meal.

Dosage adjustment

• Creatinine clearance below 50 ml/minute

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:
• liver transplant recipients who are receiving or have received immunosuppressants that may affect renal function
• elderly patients
• pregnant or breastfeeding patients
• children younger than age 16.

Administration

• Administer at least 2 hours before or after a meal.

Route	Onset	Peak	Duration
P.O.	Unknown	0.5-1.5 hr	Unknown

Adverse reactions

CNS: headache, dizziness, fatigue

GI: nausea, diarrhea, dyspepsia, increased GI enzymes

Hematologic: hematuria

Hepatic: HBV exacerbation , severe hepatomegaly

Metabolic: glycosuria, lactic acidosis

Interactions

Drug-drug. Drugs that reduce renal function or compete for active tubular secretion: increased blood levels of either drug

Drug-diagnostic tests. Alanine aminotransferase, amylase, aspartate aminotransferase, lipase, glucose, serum creatinine, total bilirubin: increased

Patient monitoring

• Monitor renal function before and during therapy, especially in liver transplant recipients who are receiving or have received immunosuppressants that may affect renal function.
☞ Monitor liver function closely for evidence of HBV exacerbation for at least several months after drug discontinuation.
☞ Monitor for lactic acidosis (associated with nucleoside analogues).

Patient teaching

• Instruct patient to take drug on empty stomach (at least 2 hours before or after a meal).
☞ Teach patient about signs and symptoms of lactic acidosis and importance of contacting prescriber if these occur.
☞ Instruct patient to immediately report worsening symptoms, such as increased yellowing of skin or eyes, dark urine, or fatigue.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.