Venetoclax is an oral medicine which comes in the form of 10mg, 50mg and 100mg tablets.

You will begin treatment on the lowest dose of venetoclax. A healthcare professional will gradually increase the dose each week over five weeks as below:

• 20mg once a day for week one
• 50mg once a day for week two
• 100mg once a day for week three
• 200mg once a day for week four
• 400mg once a day from week five onwards

Your dose is increased slowly over five weeks to reduce the risk of you developing Tumour Lysis Syndrome (TLS).

The dose you are given is also dependent on the blood test results. It is not unusual for there to be a delay in increasing the dose because of the test results.

You should not drink grapefruit juice, eat grapefruit, Seville oranges (often used in marmalades), or starfruit while you are taking venetoclax. These foods may increase the amount of Venetoclax in your blood because they contain natural compounds that can reduce your body’s ability to remove venetoclax from your system.

What is Tumour Lysis Syndrome (TLS)?

Tumour Lysis Syndrome (TLS) is a serious side effect which may occur with chemotherapy treatment. Venetoclax breaks down cancer cells and, if this happens rapidly, it can cause the cells to release uric acid into the blood. Too much uric acid can lead to kidney failure and imbalances in your blood, particularly phosphate, potassium and calcium levels.

What can be done to reduce your risk of TLS?

Drink fluids: Before you start taking Venetoclax, and whilst you are slowly increasing its dose, you should drink lots of fluid, at least one and a half to two litres a day. If you cannot drink this amount, you may be given some fluid via a drip into your vein. During your treatment you must drink lots of fluid to help your body flush out the broken-down cells and the chemicals they produce.