Newly Diagnosed Glioblastoma Multiforme:Temozolomide is used in adult patients who are newly diagnosed with glioblastoma multiforme. It is administered alongside radiotherapy initially, followed by continued use as maintenance therapy.

Refractory Anaplastic Astrocytoma: Temozolomide is also indicated for adult patients with refractory anaplastic astrocytoma, particularly those whose disease has progressed despite treatment with nitrosourea and procarbazine-containing regimens.

Temozolomide itself is inactive but is rapidly converted at normal physiological pH into an active compound called MTIC (Methyl Triazen Imidazole Carboxamide). This active compound works by damaging the DNA of cancer cells through alkylation, mainly targeting the O6 and N7 positions of guanine, leading to cell death.

Newly Diagnosed GBM: 75 mg/m for 42 days concomitant with focal radiotherapy followed by initial maintenance dose of 150 mg/m once daily for Days 1-5 of a 28-day cycle of Temozolomide for 6 cycles.

Refractory Anaplastic Astrocytoma: Initial dose 150 mg/m once daily for 5 consecutive days per 28-day treatment cycle.

Should be taken on an empty stomach. Take at least 1 hr before meals

Coadministration of valproic acid may reduce the oral clearance of temozolomide by approximately 5%. However, the clinical significance of this interaction remains unclear.

Temozolomide should not be used in patients with known hypersensitivity to any of its components. It is also contraindicated in individuals allergic to DTIC (dacarbazine), as both drugs are metabolized into the same active compound, MTIC.

Common side effects include hair loss, fatigue, nausea, vomiting, headache, constipation, loss of appetite, seizures, rash, weakness on one side of the body, diarrhea, general weakness, fever, dizziness, impaired coordination, viral infections, memory issues, and insomnia.
Severe hematologic abnormalities (Grade 3–4) may include lymphopenia, thrombocytopenia, neutropenia, and leukopenia. Allergic reactions have also been reported.

Temozolomide is classified as Pregnancy Category D. There are no well-controlled studies in pregnant women, but it may cause harm to the fetus. Women of reproductive age should avoid pregnancy during treatment.
It is unknown whether the drug passes into breast milk. Due to potential risks to nursing infants, a decision should be made to either discontinue breastfeeding or stop the medication.

Myelosuppression: Monitor Absolute Neutrophil Count (ANC) and platelet count prior to dosing and throughout treatment. Geriatric patients and women have a higher risk of developing myelosuppression. Cases of myelodysplastic syndrome and secondary malignancies, including myeloid leukemia, have been observed.

Pneumocystis carinii pneumonia (PCP): Prophylaxis is required for all patients receiving concomitant Temozolomide and radiotherapy for the 42-day regimen for the treatment of newly diagnosed glioblastoma multiforme. All patients, particularly those receiving steroids, should be observed closely for the development of lymphopenia and PCP. Complete blood counts should be obtained throughout the treatment course as specified. Fetal harm can occur when administered to a pregnant woman. Women should be advised to avoid becoming pregnant while receiving Temozolomide.

Pediatric Use: Safety and effectiveness in pediatric patients have not been established.

Renal Impairment: Caution should be exercised when Temozolomide is administered to patients with severe renal impairment.

Hepatic Impairment: Caution should be exercised when Temozolomide is administered to patients with severe hepatic impairment.

High doses may lead to severe hematologic toxicity. Reported overdose effects include pancytopenia, fever, multi-organ failure, and death. Prolonged use beyond recommended duration may cause severe bone marrow suppression and infections.
In overdose cases, blood monitoring and supportive treatment are required.

Cytotoxic chemotherapy

Store below 25°C in a dry place. Keep protected from light and moisture. Do not freeze.