Olaparib, as a PARP inhibitor, exerts anti-tumor effects by blocking the DNA repair pathway. Its drug interactions mainly involve CYP enzyme metabolism and specific drug combination risks. The following will explain the mechanism of action and drug interactions from two aspects.

1. Mechanism of action

(1) PARP inhibition: Selective inhibition of poly (ADP ribose) polymerase (PARP1/2), blocking the DNA single strand damage repair pathway in tumor cells.

(2) Synthetic lethal effect: In homologous recombination repair defective tumors such as BRCA mutations, it leads to the accumulation of DNA double strand breaks and triggers cell apoptosis.

2. Drug interactions

(1) CYP3A4 strong inducer: may significantly reduce the blood concentration of olaparib, and should be avoided in combination with drugs such as rifampicin.

(2) Strong CYP3A4 inhibitors, such as clarithromycin, may increase exposure to olaparib and require monitoring for adverse reactions.

(3) Anticoagulants: Combined use with warfarin may increase the risk of bleeding, and INR monitoring needs to be strengthened.

(4) Hormonal contraceptive pills: may affect efficacy, non hormonal contraceptive methods are recommended.

(5) Proton pump inhibitors: The combination of omeprazole and other drugs may alter drug absorption and require interval administration time.

3. Medication precautions

(1) Bone marrow suppression risk: During treatment, regular monitoring of whole blood cell count is necessary. If sustained hematological toxicity occurs, it should be interrupted or reduced, and if necessary, referred to a hematology department for evaluation.

(2) Embryotoxicity: People of childbearing age should take effective contraceptive measures. Women should confirm their pregnancy status before taking medication, and avoid pregnancy during treatment and for one month after discontinuing medication.

(3) Drug interactions: Avoid combination with potent CYP3A inhibitors (such as clarithromycin) or inducers (such as rifampicin) as they may affect efficacy or increase toxicity.

(4) Liver function monitoring: It is contraindicated for patients with severe liver damage, and close monitoring of liver function indicators is necessary for patients with mild to moderate liver damage.