How Do PARP Inhibitors Work?

Antineoplastic poly adenosine diphosphate-ribose polymerase (PARP) inhibitors are a class of drugs used to treat breast cancer, prostate cancer, ovarian cancer, fallopian tube (the tube that transports eggs released by the ovaries to the uterus), and peritoneal (layer of tissue that lines the abdomen) cancer in people who have completely or partially responded to their first or later chemotherapy treatments.

PARP inhibitors are a group of pharmacological inhibitors of the enzymes, PARP-1 and PARP-2, which play an essential role in DNA repair. The inhibition of PARP enzymatic activity and increased formation of PARP-DNA complexes result in DNA damage and apoptosis (death of cells which occurs as a normal and controlled part of an organism’s growth or development).

They are a type of targeted therapy that works by preventing cancer cells from repairing and inducing cell death.

PARP inhibitors are administered orally as a tablet or a capsule twice daily with or without food.

PARP inhibitors work in the following ways:

• They are a targeted cancer therapy that works by inhibiting an enzyme in cells called "PARP" which plays a key role in DNA repair.
• Blocking PARP helps in preventing cancerous cells from repairing their damaged DNA, eventually leading to their death.

Antineoplastic PARP inhibitors are used to treat conditions such as:

• Ovarian cancer
• Breast cancer
• Pancreatic cancer
• Fallopian tube cancer
• Peritoneal cancer
• Metastatic castration-resistant prostate cancer

Some of the common side effects include:

• Nausea
• Vomiting
• Constipation
• Diarrhea
• Headache
• Heartburn
• Tiredness/weakness
• Muscle/joint/back pain
• Mouth sores
• Loss of appetite
• Abdominal pain
• Other rare side effects include:
• Dizziness 
• Fatigue 
• Weight loss
• Hair loss
• Chest pain
• Anemia (low red blood cell count)
• Insomnia 
• Shortness of breath
• Chills, sore throat, fever, or cough
• Rash/hives/itching
• Thrombocytopenia (low blood platelet count)
• Hypertension (high blood pressure)
• Hypocalcemia (low blood calcium level)
• Hypophosphatemia (low blood phosphate level)
• Painful, frequent, burning, or difficult urination
• Peripheral edema (swelling of lower legs or hands)
• Increased creatinine 

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of antineoplastic PARP inhibitors include:

• Lynparza
• Niraparib
• Olaparib
• Rubraca
• Rucaparib
• Talazoparib
• Talzenna
• Zejula