Tezacaftor with ivacaftor

How it works

Tezacaftor is a corrector that improves processing and trafficking of CFTR protein to the cell surface, while ivacaftor is a potentiator that increases channel gating, together enhancing chloride transport.

Prescribing in practice

• Liver function should be assessed before and during treatment, as transaminase elevations can occur and caution is needed in hepatic impairment.
• Clinically significant interactions occur with strong CYP3A inducers and inhibitors, requiring dose adjustment or avoidance.
• Cataracts have been reported in children, so ophthalmological assessment is advised in paediatric patients, and treatment is initiated in specialist cystic fibrosis centres.

Monitoring

Check liver function before starting and periodically during treatment, and arrange eye examinations in children.

Counselling the patient

• Take the medicine with fat-containing food as directed for proper absorption.
• Avoid grapefruit and tell your team about all other medicines, including herbal products.
• Report yellowing of the skin or eyes, dark urine or abdominal pain.

Evidence & guidelines

NICE has recommended CFTR modulator therapies including tezacaftor with ivacaftor for eligible patients with cystic fibrosis under a managed access arrangement.