Description

Temozolomide 100mg Capsules – Uses, Dosage, Side Effects & Safety Information

Overview

Temozolomide 100mg is an oral chemotherapy medication widely used in the treatment of aggressive brain cancers such as glioblastoma multiforme (GBM) and anaplastic astrocytoma. It is an imidazotetrazine alkylating agent that works by damaging cancer cell DNA, leading to cell death. In Pakistan, these capsules are usually imported and may be high-priced, making consultation with oncologists and procurement through proper medical channels essential.

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Indications

Temozolomide is prescribed for:

• Newly diagnosed glioblastoma multiforme (GBM) in adults: Used along with radiotherapy and continued as maintenance treatment.

• Refractory anaplastic astrocytoma in adults: Indicated for patients whose disease has progressed on previous regimens containing nitrosourea and procarbazine.

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Dosage & Administration

• Standard Dose: 100mg per square meter (m²) of body surface area, orally, once daily.

• Duration: Maximum of 42–49 days when given in combination with focal radiotherapy.

• Administration Tip: Take on an empty stomach (1 hour before or 2 hours after meals) to improve absorption and reduce nausea.

⚠️ Important: Never crush or open capsules. Handle with gloves due to hazardous nature.

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Mechanism of Action

Temozolomide is a prodrug that rapidly converts to its active metabolite MTIC (5-(3-methyltriazen-1-yl)imidazole-4-carboxamide) at physiological pH.

• DNA Damage: MTIC methylates DNA at the O6 and N7 guanine positions, causing DNA strand breaks and apoptosis.

• Resistance Factors:

  • MGMT gene activity can repair O6-methylguanine lesions, reducing drug effectiveness.

  • Mismatch repair (MMR) proteins also influence sensitivity to Temozolomide.

• Sensitive Cells: Tumors with low MGMT expression respond better to treatment.

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Clinical Benefits

Studies have shown significant improvements in survival with Temozolomide:

• Glioblastoma Multiforme: Median survival extended to 15–16 months with chemoradiotherapy.

• With Tumor-Treating Fields (TTF): Median survival further improved to 20.9 months.

• Anaplastic Glioma (without 1p/19q codeletion): 5-year survival rates of 56% vs 44% when combined with radiotherapy.

• Recurrent Malignant Glioma: Median survival of 49 weeks with better progression-free rates in Grade 3 tumors.

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Safety & Side Effects

Common Side Effects:

• Nausea, vomiting, constipation, fatigue, headache

• Low blood cell counts (myelosuppression)

Serious Risks:

• Severe bone marrow suppression

• Increased risk of infections

• Liver toxicity

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Handling & Storage

• Handle capsules with protective gloves; avoid crushing or inhaling powder.

• Store at room temperature (20–25°C), away from light and moisture.

• Keep out of reach of children and pets.

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Pregnancy & Breastfeeding Warnings

• Pregnancy: Teratogenic – may cause birth defects and fetal harm. Contraindicated during pregnancy.

• Contraception: Required during treatment and for 6 months after last dose.

• Breastfeeding: Contraindicated; drug may cause serious harm to infants.

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Drug & Food Interactions

• Food: Slows absorption; reduces peak plasma concentration by ~32%. Best taken on an empty stomach.

• Drug Interactions: Over 260 drug interactions documented. Notable ones include valproic acid and vaccines. Always inform your doctor about all medications and supplements.

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Disposal Guidelines

• Do not discard in household trash or flush in water systems.

• Consult a pharmacist or oncologist for safe disposal of unused capsules.

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Key Ingredients

• Active: Temozolomide 100mg

• Excipient: Lactose

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Conclusion

Temozolomide 100mg capsules are a cornerstone in brain cancer treatment, particularly for GBM and anaplastic astrocytoma. While highly effective, they require strict medical supervision, careful handling, and safe disposal. Patients in Pakistan should obtain Temozolomide only through licensed oncologists and trusted pharmacies due to variable availability and cost.