Lynparza Drug Interactions: What to Avoid and What to Tell Your Doctor

Lynparza (olaparib) has several clinically significant drug interactions that every patient—and their caregivers—should know about. The most important involve drugs and foods that affect a liver enzyme called CYP3A, which is responsible for breaking down Lynparza in your body. Changes in CYP3A activity can dramatically increase or decrease Lynparza's effects.

How Lynparza Is Metabolized (Why Interactions Happen)

Lynparza is primarily broken down (metabolized) by the CYP3A enzyme in the liver. Many common medications, supplements, and foods either inhibit or induce this enzyme:

CYP3A inhibitors slow down CYP3A → Lynparza is metabolized more slowly → blood levels rise → increased risk of side effects

CYP3A inducers speed up CYP3A → Lynparza is broken down faster → blood levels fall → reduced effectiveness

Drugs to AVOID with Lynparza: Strong CYP3A Inhibitors

Strong CYP3A inhibitors can increase Lynparza's blood levels by up to 170%. Avoid these drugs when possible:

Antifungals: itraconazole, ketoconazole, voriconazole, posaconazole

Antibiotics: clarithromycin, telithromycin

HIV protease inhibitors: ritonavir, lopinavir/ritonavir, indinavir, saquinavir, nelfinavir

Hepatitis C antivirals: boceprevir, telaprevir

Other: nefazodone (antidepressant)

If you must take a strong CYP3A inhibitor, your oncologist should reduce your Lynparza dose to 100 mg twice daily (one 100 mg tablet BID) to compensate.

Dose Reduction Required: Moderate CYP3A Inhibitors

Moderate CYP3A inhibitors increase Lynparza levels by a predicted 121% or more. If these must be used, dose reduce to 150 mg twice daily:

Antifungals: fluconazole

Antibiotics: erythromycin, ciprofloxacin

Heart/blood pressure: diltiazem, verapamil, amiodarone

Cancer drugs: crizotinib, imatinib

HIV drugs: atazanavir, darunavir/ritonavir, fosamprenavir, aprepitant

Drugs to AVOID with Lynparza: Strong and Moderate CYP3A Inducers

CYP3A inducers can decrease Lynparza's blood concentration by up to 87%, potentially making the drug ineffective. Avoid these whenever possible:

Strong CYP3A inducers (avoid entirely): rifampin (rifampicin), phenytoin, carbamazepine, St. John's Wort

Moderate CYP3A inducers (avoid if possible): efavirenz (HIV), bosentan, etravirine, modafinil, nafcillin, apalutamide

Important note for prostate cancer patients: Apalutamide (Erleada) and enzalutamide (Xtandi) are both strong CYP3A4 inducers. If you are on Lynparza for prostate cancer, discuss these combinations carefully with your oncologist.

Food Interactions: Grapefruit and Seville Oranges

Grapefruit, grapefruit juice, Seville oranges (often found in marmalade), and Seville orange juice are natural CYP3A inhibitors. They can increase Lynparza blood levels and raise the risk of side effects. Avoid these entirely while taking Lynparza. Regular orange juice is fine.

Supplements to Discuss with Your Doctor

St. John's Wort: A strong CYP3A inducer. Avoid entirely during Lynparza treatment.

Herbal products and supplements: Many have unknown effects on CYP3A. Always tell your oncologist about every supplement you're taking.

Myelosuppressive Drug Combinations

Clinical studies have shown that combining Lynparza with other myelosuppressive anticancer agents (drugs that suppress bone marrow function) can potentiate and prolong myelosuppressive toxicity. This is particularly relevant if you are receiving Lynparza in combination with bevacizumab or other agents. Your oncologist will closely monitor your blood counts.

The Complete List: Tell Your Doctor About All of These

Before starting Lynparza, give your oncologist and pharmacist a complete list of:

All prescription medications

All over-the-counter medications

All vitamins and supplements (including herbal products)

Your full diet, particularly regular use of grapefruit or marmalade

For a complete guide to Lynparza side effects beyond interactions, see: Lynparza Side Effects: What to Expect and When to Call Your Doctor.

Need help finding a specialty pharmacy for your Lynparza prescription? medfinder calls pharmacies near you to check availability so you don't have to.