Niranib 100 mg, containing the active ingredient Niraparib, is an oral poly (ADP-ribose) polymerase (PARP) inhibitor indicated for the treatment and maintenance therapy of certain advanced ovarian, fallopian tube, or primary peritoneal cancers. It is particularly effective in patients who have achieved a response to platinum-based chemotherapy and is used to reduce the risk of cancer recurrence. Niraparib provides a targeted approach by exploiting deficiencies in DNA repair mechanisms commonly found in these cancers, especially those with BRCA mutations or homologous recombination deficiency (HRD).

Indications

Niranib 100 mg works by inhibiting PARP enzymes, which play a critical role in the repair of single-strand DNA breaks. By blocking PARP activity, the drug causes accumulation of DNA damage in cancer cells, leading to cell death, particularly in tumor cells deficient in homologous recombination repair pathways. This targeted mechanism makes Niraparib highly effective in preventing disease progression in patients with advanced ovarian cancers who have responded to prior platinum therapy.

Pharmacology

Niraparib is a selective PARP-1 and PARP-2 inhibitor. Inhibition of PARP leads to the accumulation of DNA single-strand breaks, which convert into double-strand breaks during DNA replication. Tumor cells lacking efficient homologous recombination repair pathways, such as those with BRCA mutations, are unable to repair this damage, resulting in apoptosis.

• Absorption: Niraparib is rapidly absorbed after oral administration, with peak plasma concentration occurring within 3–4 hours.

• Distribution: It is highly protein-bound (~83%) and widely distributed in tissues.

• Metabolism: Primarily metabolized by carboxylesterases to inactive metabolites.

• Elimination: Excreted mainly via urine and feces, with a terminal half-life of approximately 36 hours, supporting once-daily dosing.

Dosage & Administration

Niranib 100 mg is administered orally once daily, with or without food. The starting dose may be individualized based on body weight and platelet count to minimize hematologic toxicity.

• Standard Dosage: 300 mg orally once daily for patients weighing ≥77 kg with platelet counts ≥150,000/µL.

• Adjusted Dosage: 200 mg orally once daily for patients weighing <77 kg or with baseline platelet counts <150,000/µL.

Treatment continues until disease progression or unacceptable toxicity. Capsules should be swallowed whole and not opened, crushed, or chewed.

Drug Interactions

• Niraparib is primarily metabolized via non-CYP pathways, so interactions are less common, but caution is advised with drugs that affect platelet function or hematopoiesis.

• Avoid concomitant use with strong P-glycoprotein inhibitors or inducers that may alter drug exposure.

Contraindications

• Known hypersensitivity to Niraparib or any components of the formulation.

• Caution in patients with preexisting hematologic abnormalities, liver disease, or renal impairment.

Side Effects

Common adverse effects include fatigue, nausea, thrombocytopenia, anemia, neutropenia, and hypertension. Rare but serious effects may include myelodysplastic syndrome, acute leukemia, severe hematologic toxicity, and cardiovascular events. Regular monitoring of complete blood counts, blood pressure, and liver function is essential.

Pregnancy & Lactation

• Niraparib may cause fetal harm; effective contraception is required during treatment and for six months after discontinuation.

• The drug’s presence in breast milk is unknown; breastfeeding is not recommended during therapy and for at least one week after the last dose.

Precautions & Warnings

• Monitor hematologic parameters weekly for the first month, then monthly.

• Monitor blood pressure regularly; hypertension may require dose adjustments.

• Dose modifications or interruptions may be needed for severe hematologic, hepatic, or cardiovascular adverse events.

Therapeutic Class

PARP Inhibitor / Targeted Cancer Therapy

Storage Conditions

Store in a cool, dry place below 30°C, protected from light. Keep out of reach of children.