Prescription medication · Nucleoside Analog (HBV)
entecavir
Also sold as Baraclude. Entecavir treats chronic hepatitis B virus (HBV) infection.
Data updated 2026-05-15
- 11,247
- FDA reportsModerately reported
- 1
- InteractionFew interactions
- 99% less
- Generic vs brandHuge savings
- 3
- Recall records
What the data shows
entecavir (Baraclude) is a prescription Nucleoside Analog (HBV), reported less often than most tracked drugs (11,247 FDA reports), whose generic costs a fraction of the brand (about 99% less).
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
entecavir (Baraclude) is a prescription Nucleoside Analog (HBV). Entecavir treats chronic hepatitis B virus (HBV) infection.
Entecavir is a medicine used to treat chronic hepatitis B infection. It helps to lower the amount of the virus in your body.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Brand Price
$44.09/unit
Generic Price
$0.29/unit
Generic Savings
99%
Generic Available
Yes (10 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Entecavir treats chronic hepatitis B virus (HBV) infection.
Common side effects
Headache, Tiredness, Dizziness
Key warnings
Entecavir has the following warnings: * Stopping entecavir can cause a severe return of hepatitis B.
The sections below are summarized in plain English from entecavir's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Entecavir belongs to a class of drugs called nucleoside analogs. It works by blocking an enzyme that the hepatitis B virus needs to multiply. This helps to lower the amount of virus in your body and improve your liver health.
How to Take It
Take entecavir exactly as your doctor tells you to. For adults and adolescents 16 years and older, the usual dose is 0.5 mg or 1 mg once a day. Children's doses are based on their weight. Take entecavir on an empty stomach, at least 2 hours after a meal and 2 hours before your next meal.
This is a plain-language summary of entecavir's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. There is a pregnancy registry to track outcomes in women who take entecavir during pregnancy. Talk to your doctor about the risks and benefits of taking entecavir while pregnant.
This is a plain-language summary of entecavir's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take your next dose at the regular time.
This is a plain-language summary of entecavir's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store entecavir tablets in a tightly closed container at room temperature, away from light.
Side Effects (from patient reports)
Based on 11,247 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for entecavir, by number of reports
- Death
Death
539 reports
- The virus is no longer responding to the medicine
The virus is no longer responding to the medicine
401 reports
- Diarrhea
Diarrhea
363 reports
- Tiredness
Tiredness
353 reports
- Fever
Fever
348 reports
- Hepatitis B
Hepatitis B
327 reports
- Nausea
Nausea
313 reports
- Low platelet count
Low platelet count
289 reports
- Pneumonia
Pneumonia
286 reports
- Anemia
Anemia
229 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for entecavir each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where entecavir sits
entecavir has more FDA adverse-event reports than 42% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is entecavir; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 11,247 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
11,247
Reports Mentioning Death
1,842
16.4% of reports — not proof of cause
Hospitalization Reports
4,285
Top Indication
Hepatitis B
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DEATH | 539 |
| 4 | DRUG RESISTANCE | 401 |
| 5 | DIARRHOEA | 363 |
| 6 | FATIGUE | 353 |
| 7 | PYREXIA | 348 |
| 8 | HEPATITIS B | 327 |
| 9 | NAUSEA | 313 |
| 10 | PLATELET COUNT DECREASED | 289 |
| 11 | PNEUMONIA | 286 |
| 12 | ANAEMIA | 229 |
| 13 | RENAL IMPAIRMENT | 225 |
| 14 | HEPATIC FAILURE | 221 |
| 15 | WHITE BLOOD CELL COUNT DECREASED | 221 |
| 16 | NEUTROPENIA | 218 |
| 17 | ASTHENIA | 217 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Entecavir has the following warnings: * Stopping entecavir can cause a severe return of hepatitis B. Your liver function should be checked for several months after stopping. * If you have both HIV and hepatitis B, entecavir may make your HIV medicine less effective. Entecavir is not recommended if you have HIV and are not taking HIV medicine. * Entecavir can cause lactic acidosis (a buildup of acid in the blood) and severe liver problems. These can be fatal.
Known Drug Interactions
Co-administration of entecavir with lamivudine, adefovir dipivoxil, or tenofovir disoproxil fumarate did not result in significant drug interactions.
Mechanism: These two medications do not have a significant effect on each other when taken at the same time.
What to do: No special changes are usually needed, but you should still take them exactly as your doctor prescribes.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
What should I do if I feel sick while taking entecavir?
Can I take entecavir with other medications?
How long will I need to take entecavir?
Will entecavir cure my hepatitis B?
Can I drink alcohol while taking entecavir?
What tests will I need while taking entecavir?
Can I spread hepatitis B to others while taking entecavir?
Is there a generic version of entecavir available?
What do the numbers on the tablet mean?
Can children take entecavir?
What are the common side effects of entecavir?
Does entecavir interact with other medications?
What drug class is entecavir?
Is there a generic version of entecavir?
Is entecavir safe during pregnancy?
Has entecavir been recalled?
Active Recalls
Failed impurity/degradation specifications:Out of Specification result for an individual organic impurity
Zydus Pharmaceuticals (USA) Inc
Failed impurity/degradation specifications:Out of Specification result for an individual organic impurity
Zydus Pharmaceuticals (USA) Inc
Failed Impurity/Degradation Specifications
Zydus Pharmaceuticals (USA) Inc
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Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for entecavir
The FDA label for entecavir (sold under brand names such as Baraclude) classifies it as a prescription-only medication in the Nucleoside Analog (HBV) class. Entecavir treats chronic hepatitis B virus (HBV) infection. Official labeling lists 4 commonly reported side effects, including Headache, Tiredness, Dizziness.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 11,247 voluntary reports. The database also lists 1 documented drug interaction derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS shows a generic unit cost of $0.29 versus $44.09 for the brand - a 99% generic savings.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history (currently 3 recall records on file), and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: November 24, 2019
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages