Drug, Food and Supplement — Interactions With Olaparib

Paracetamol is not known to interact significantly with olaparib through the CYP3A4 pathway, and it is generally considered safe to use for mild pain or fever. Always tell your oncology team what you are taking, including over-the-counter medicines, so they have a complete picture. Your team may have specific guidance on dose and frequency based on your liver function and blood counts at any given time.

Proton pump inhibitors such as omeprazole and pantoprazole, and antacids like Gelusil or Digene, are not known to significantly interact with olaparib. Many people on olaparib use these medicines to manage nausea or heartburn, both of which are common side effects. Let your oncology team know what you are taking so your complete list stays current.

Whether your antidepressant is safe to continue depends on which one you take. Most antidepressants commonly prescribed in India — including escitalopram and sertraline — are not significant CYP3A4 interactors and can generally be continued alongside olaparib. Never stop or change your antidepressant without discussing it with both your oncologist and the doctor who prescribed it. Bring your full medicine list to every appointment so both teams can review it together.

The interaction risk from many Ayurvedic and herbal preparations is difficult to assess because their exact composition is not always standardised. This is not a reason to stop them without discussion — it is a reason to tell your oncology team exactly what you are taking, including the brand name and daily dose. St John's Wort must be stopped while you are on olaparib. For other preparations, your pharmacist can help check what is known about their ingredients and enzyme interactions.

Whether your statin needs review depends on which one you take. Some statins — including simvastatin — are processed through CYP3A4, and there may be a modest interaction. Do not stop your statin on your own, because stopping cholesterol medicine carries its own risks. Bring your complete medicine list to your next oncology appointment and ask your pharmacist to check the specific combination. Your oncologist and the doctor managing your cholesterol can decide together whether any adjustment is needed.

Tell your oncology team as soon as you realise, and do not stop olaparib on your own. In most cases, a single accidental dose of an interacting medicine is managed without any change to your olaparib. Your team will ask which medicine it was, how much you took, and for how long — and they will decide from there whether any monitoring or adjustment is needed.

Before filling any new prescription, tell the prescribing doctor you are on olaparib and ask the pharmacist to check for interactions. Pharmacists are trained to identify drug interactions and can flag a concern before you take the first dose. If the new medicine is on the avoid list, the prescribing doctor may be able to suggest an alternative. Never stop or adjust olaparib without your oncologist's agreement — that decision is theirs to make with you.

Even a small amount matters. Grapefruit contains compounds that block the intestinal form of CYP3A4, and even a small portion can have an unpredictable effect on how much olaparib reaches your bloodstream. The effect also lingers well beyond the meal itself. This applies equally to grapefruit juice, Seville oranges used in marmalades, and pomelo. The recommendation in olaparib prescribing guidance is complete avoidance — not moderation.