Venetoclax

Pronunciation: pronunciation varies by local usage.

Generic name: venetoclax
Brand names: Venclexta
Drug class: B-cell lymphoma-2 (BCL-2) inhibitor
Form: Film-coated tablet and kit
Route: Oral
Legal status: Prescription antineoplastic (anticancer) medicine

Availability and supply rules vary by country

Trade names by country: United States · Canada

What venetoclax is and how it works

Venetoclax is an oral B-cell lymphoma-2 (BCL-2) inhibitor used to treat certain blood cancers. (1)

In the reviewed US label, venetoclax is indicated for adults with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), and with specified medicines for eligible adults with newly diagnosed acute myeloid leukemia (AML). Tumor lysis syndrome is an important risk when treatment begins, so the treatment team uses a planned dose ramp-up, hydration, preventive medicines, and blood testing based on individual risk.

Mechanism of action: how venetoclax works

Venetoclax is a B-cell lymphoma-2 (BCL-2) inhibitor. (1)

What venetoclax is used for

Chronic lymphocytic leukemia or small lymphocytic lymphoma

Venetoclax is indicated for treatment of adult patients with CLL or SLL. (1)

Newly diagnosed acute myeloid leukemia

Venetoclax is indicated in combination with azacitidine, decitabine, or low-dose cytarabine for adults aged 75 years or older, or adults with comorbidities that preclude intensive induction chemotherapy. (1)

Before taking venetoclax

Do not take / not appropriate for

Concomitant use of a strong CYP3A inhibitor is contraindicated when initiating venetoclax and during the ramp-up phase for CLL/SLL. (CLL/SLL initiation and ramp-up phase) (1)

Tell your clinician about

All prescription medicines, non-prescription medicines, and other products, because important CYP3A and P-glycoprotein interactions can affect venetoclax treatment.
Any kidney problem or reduced kidney function, because tumor lysis syndrome risk increases when creatinine clearance is below 80 mL/min.
Any liver problem, particularly severe hepatic impairment.
Pregnancy, plans for pregnancy, or breastfeeding.
Any planned vaccination, including a live attenuated vaccine.
Any fever, signs of infection, or previous serious infection.

(1)

How to take venetoclax

Take venetoclax by mouth once daily with a meal and water, exactly according to the treatment plan set by the oncology team.
Swallow tablets whole. Do not chew, crush, or break them.
The starting schedule depends on the blood cancer and treatment regimen. For CLL/SLL, the reviewed US label uses a 5-week dose ramp-up; for AML, it uses a 3- to 4-day ramp-up with the final daily dose depending on the combination regimen.
Tumor lysis syndrome prevention and monitoring can include anti-hyperuricemic medicines, hydration, blood tests, and, for higher-risk people, intravenous hydration, more frequent monitoring, or hospitalization.
Do not change the dose, ramp-up schedule, or treatment combination yourself; the oncology team must manage treatment decisions.

(1)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)

Missed dose

Missed-dose instructions were not captured in the reviewed research notes. Contact the prescribing oncology team or pharmacist for instructions rather than taking an extra dose.

Overdose

Overdose-management instructions were not captured in the reviewed research notes. If more venetoclax than prescribed may have been taken, urgently contact the prescribing oncology service, a poison-information service, or emergency medical services as appropriate. (1)

Side effects

Side effects differ between CLL/SLL and AML treatment settings. Blood-count changes and infections can be serious and require oncology-team monitoring.

Common effects reported in CLL/SLL

What to notice: Neutropenia, thrombocytopenia, anemia, diarrhea, nausea, upper respiratory tract infection, cough, musculoskeletal pain, fatigue, and edema were common adverse reactions (at least 20%).

What to do: Report persistent, troublesome, or worsening symptoms to the oncology team. (1)

Common effects reported in AML

What to notice: Nausea, diarrhea, thrombocytopenia, constipation, neutropenia, febrile neutropenia, fatigue, vomiting, edema, pyrexia, pneumonia, dyspnea, hemorrhage, anemia, rash, abdominal pain, sepsis, musculoskeletal pain, dizziness, cough, oropharyngeal pain, and hypotension were common adverse reactions (at least 30%).

What to do: Report new or worsening symptoms to the oncology team promptly. (1)

Possible infection or febrile neutropenia

What to notice: Fever or other signs of infection. Serious and fatal infections, including pneumonia and sepsis, have occurred.

What to do: Contact the oncology team promptly for assessment. (1)

Low blood counts or bleeding

What to notice: Symptoms potentially related to low neutrophils, platelets, or red blood cells, including bleeding or worsening tiredness.

What to do: Contact the oncology team promptly; blood-count monitoring and any treatment decisions require clinician assessment. (1)

Serious warnings

Tumor lysis syndrome — emergency

Symptoms: Changes in blood chemistries consistent with tumor lysis syndrome can occur as early as 6 to 8 hours after the first dose. The reviewed notes identify potassium, uric acid, phosphorus, calcium, and creatinine as monitored blood chemistries.

Action: Follow the oncology team's hydration, preventive-medicine, blood-testing, and monitoring plan exactly. Seek urgent medical assessment for concerning symptoms or if the oncology team directs urgent care; risk management may require intravenous hydration, more frequent monitoring, or hospitalization. (1)

Serious or fatal infection — urgent

Symptoms: Fever, pneumonia, sepsis, or other signs of infection. Fatal and serious infections have occurred.

Action: Seek prompt medical assessment and notify the oncology team. (1)

Embryo-fetal toxicity — urgent

Symptoms: Venetoclax may cause embryo-fetal harm; animal studies showed post-implantation loss and decreased fetal weight.

Action: Discuss pregnancy prevention and any possible pregnancy promptly with the prescribing clinician. Effective contraception is advised during treatment and for 30 days after the last dose. (1)

Interactions

Medicine or test	Effect	Action
Strong CYP3A inhibitors	These medicines can require major venetoclax dose changes. Their concomitant use is contraindicated at venetoclax initiation and during the CLL/SLL ramp-up phase. In AML, venetoclax dose reduction is required when a strong CYP3A inhibitor is coadministered.	The oncology prescriber and pharmacist must review all medicines before venetoclax is started or changed. (1)
Posaconazole	The reviewed US label specifies a reduced steady venetoclax dose of 70 mg for CLL/SLL with posaconazole, or an AML Day 1 to 4 ramp-up of 10 mg, 50 mg, and 70 mg.	Use only the prescriber-directed regimen; this interaction requires regimen-specific oncology and pharmacy management. (1)
Moderate CYP3A inhibitors	These medicines require a venetoclax dose reduction of at least 50%.	Ask the oncology prescriber or pharmacist to review the medicine list before use together. (1)
CYP3A inducers	These medicines can decrease venetoclax plasma concentrations.	Coadministration should be avoided through prescriber-managed treatment planning. (1)
P-glycoprotein substrates	The P-glycoprotein substrate should be taken at least 6 hours before venetoclax.	Confirm the timing plan with the oncology prescriber or pharmacist. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Older adults and adults with comorbidities with newly diagnosed AML

The reviewed US indication includes venetoclax with azacitidine, decitabine, or low-dose cytarabine for newly diagnosed AML in adults aged 75 years or older, or adults with comorbidities that preclude intensive induction chemotherapy. (1)

Pregnancy and breastfeeding

Venetoclax may cause embryo-fetal harm. Effective contraception is advised during treatment and for 30 days after the last dose. Women are advised not to breastfeed during treatment. (1)

Kidney impairment

Reduced renal function, defined in the reviewed notes as creatinine clearance below 80 mL/min, increases tumor lysis syndrome risk and may require enhanced monitoring and hydration measures. (1)

Severe hepatic impairment

For severe hepatic impairment (Child-Pugh Class C), the reviewed US label directs a 50% reduction in the once-daily venetoclax dose. The treating clinician must determine the individual regimen. (1)

Children and adolescents

Pediatric dosing and safety data were not captured in this research pass and remain unresolved. (1)

Monitoring

Before starting

Confirm the diagnosis, indication, combination regimen where applicable, and clinician-directed ramp-up schedule.
Assess tumor lysis syndrome risk in every patient and plan preventive anti-hyperuricemic medication, hydration, and blood-chemistry monitoring.
Review kidney function, including whether creatinine clearance is below 80 mL/min, because this increases tumor lysis syndrome risk.
Review all medicines for CYP3A and P-glycoprotein interactions.
Assess pregnancy-related risk, contraception needs, breastfeeding, and planned live attenuated vaccines.

During treatment

Monitor blood chemistries for tumor lysis syndrome, including potassium, uric acid, phosphorus, calcium, and creatinine.
For low tumor burden, the reviewed label describes outpatient blood-chemistry monitoring before dosing and at 6 to 8 hours and 24 hours after initial doses.
For medium tumor burden, the reviewed label describes the same schedule, with hospitalization considered when creatinine clearance is below 80 mL/min.
For high tumor burden, the reviewed label describes hospitalization and blood-chemistry monitoring before dosing and at 4, 8, 12, and 24 hours after dosing.
Monitor blood counts and assess for neutropenia, febrile neutropenia, infections, and other adverse effects.

(1)

Storage

Storage instructions were not captured in the reviewed research notes. Use the dispensing label and current product packaging, or ask the pharmacist.

Professional information

Clinician-facing context only. Use the current local product information, indication-specific regimen, tumor lysis syndrome risk assessment, prophylaxis, monitoring protocol, and interaction-management guidance.

United States

Indication: CLL/SLL

Dose summary: The reviewed US label uses a 5-week ramp-up: Week 1, 20 mg once daily; Week 2, 50 mg once daily; Week 3, 100 mg once daily; Week 4, 200 mg once daily; Week 5 and onward, 400 mg once daily as the target maintenance dose.

Renal context: Reduced renal function, with creatinine clearance below 80 mL/min, increases tumor lysis syndrome risk and requires enhanced monitoring and hydration measures. Medium tumor burden with creatinine clearance below 80 mL/min warrants consideration of hospitalization. (1)

United States

Indication: Newly diagnosed AML with azacitidine, decitabine, or low-dose cytarabine

Dose summary: The reviewed US label uses a 3- to 4-day ramp-up: Day 1, 100 mg; Day 2, 200 mg; Day 3, 400 mg; Day 4 onward, 400 mg to 600 mg daily depending on the combination regimen.

Renal context: Reduced renal function, with creatinine clearance below 80 mL/min, increases tumor lysis syndrome risk and requires enhanced monitoring and hydration measures. (1)

Other regions

Indication: Any venetoclax use

Dose summary: Country-specific dosing and product information are unresolved because no UK, EU, or other regional regulator source was reviewed in this research pass.

Renal context: Country-specific renal guidance outside the reviewed US label is unresolved. (1)

Mechanism of action

Hepatic guidance

For severe hepatic impairment (Child-Pugh Class C), reduce the venetoclax once-daily dose by 50% according to the reviewed US label.

Overdose note

Specific overdose-management guidance was not captured in the reviewed research notes. (1)

Frequently asked questions

Why does venetoclax start with a lower dose?

For CLL/SLL, venetoclax uses a 5-week dose ramp-up to reduce tumor burden and tumor lysis syndrome risk. AML uses a shorter 3- to 4-day ramp-up. The oncology team selects and supervises the correct regimen. (1)

Can I crush or break a venetoclax tablet?

No. Tablets should be swallowed whole and should not be chewed, crushed, or broken. (1)

Can I have a live vaccine while taking venetoclax?

Live attenuated vaccines should not be given before, during, or after venetoclax treatment until B-cell recovery. Discuss all planned vaccines with the oncology team. (1)

Why does my cancer team need to know every medicine I take?

Strong or moderate CYP3A inhibitors, CYP3A inducers, and P-glycoprotein substrates can require avoidance, dose changes, or timing changes with venetoclax. (1)

What is the mechanism of action of venetoclax?

Venetoclax is a B-cell lymphoma-2 (BCL-2) inhibitor. (1)

What is the generic name of Venetoclax?

The generic name is venetoclax. It is sold under brand names including Venclexta. (1)

What class of drug is venetoclax?

Venetoclax is classed as: B-cell lymphoma-2 (BCL-2) inhibitor. (1)

References

VENCLEXTA — venetoclax kit / tablet, film coatedU.S. Food and Drug Administration (DailyMed) · United States · accessed 2026-08-05 · source 1
Venetoclax — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 2
Venclexta — FDA approval record (Drugs@FDA NDA208573)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 3
venetoclax — RxNorm normalized drug concept (RXCUI 1747556)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 4

Brand names by country

Single-ingredient venetoclax names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

Venclexta10 mg, 50 mg, 100 mg · abbvie inc.

Canada

VENCLEXTA

View brands in additional countries.