Is Temozolomide (Temodur) Ototoxic?
Temozolomide is not ototoxic. There is no evidence in major clinical guidelines, FDA labeling information, or clinical trials demonstrating ototoxicity as a recognized adverse effect of temozolomide.
Established Toxicity Profile of Temozolomide
The well-documented toxicities of temozolomide are primarily hematologic and do not include ototoxicity:
- Myelosuppression is the dose-limiting toxicity, particularly thrombocytopenia and neutropenia 1
- Neutropenia occurs early (2-3 weeks after administration) 1
- Hematologic toxicity can be severe, including grade 3-4 thrombocytopenia and neutropenia, particularly with dose-dense regimens 2
- Lymphocytopenia is common and can be profound, especially with extended dosing schedules 3
Other Recognized Adverse Effects
Beyond hematologic toxicity, temozolomide causes:
- Gastrointestinal effects: Nausea and vomiting (grades 1-2 most common) 4
- Infectious complications: Opportunistic infections including Pneumocystis pneumonia, requiring prophylaxis during concurrent radiotherapy 1
- Rare severe toxicities: Life-threatening infections and severe hematologic complications 5
- Hepatotoxicity: Rare cases reported 6
Why Ototoxicity Is Not a Concern
The major glioma treatment guidelines from EANO (2021) 6, ASCO-SNO (2022) 6, and extensive phase I/II trials 2, 4 make no mention of ototoxicity or hearing loss as adverse effects of temozolomide. This is in stark contrast to platinum-based chemotherapy agents (cisplatin, carboplatin), where ototoxicity is a well-established and frequently documented toxicity 6.
Clinical Implications
You do not need to monitor for hearing loss or counsel patients about ototoxicity when prescribing temozolomide. Instead, focus monitoring on: