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Alkylator

Temozolomide

Temodar · TMZ

Alkylator · approved 1999 · 6 references

The glioblastoma standard that is kind to the kidney but can occasionally drop the sodium.

Signature injury
SIADH / Hyponatremia
Severity
Mild
Reversibility
Reversible
Onset
During cycles of therapy; variable.

Signature kidney injury & incidence

SIADH / Hyponatremia.

Generally renally well tolerated; renal clearance of the parent drug is a minor elimination pathway and dedicated PubMed searches for temozolomide nephrotoxicity/SIADH return essentially no indexed series. Hyponatremia/SIADH is an occasional, case/toxicity-table-level event, and rare acute interstitial nephritis has been reported in combination contexts.

Source: Pouratian et al., J Neurooncol 2006

Reported injury signatures: SIADH / Hyponatremia, Electrolyte Disturbance.

Renal toxicity profile

  1. SIADH / HyponatremiaPrimary
  2. Electrolyte DisturbanceSecondary

Onset timing & rechallenge

Variable / unpredictable — SIADH arises during therapy cycles with a variable, unpredictable onset.

Mechanism of kidney injury

Direct tubular toxicity is not characteristic; the parent drug is largely eliminated by spontaneous chemical degradation with only a minor renal pathway, underpinning its renal safety. The relevant renal-electrolyte signal is occasional SIADH-type free-water retention with dilutional hyponatremia, compounded by CNS disease, nausea/vomiting and co-medications. A rare case of acute interstitial nephritis (with nephrogenic diabetes insipidus) has been described alongside trimethoprim-sulfamethoxazole.

Clinical presentation

Hyponatremia, usually mild and detected on routine monitoring; serum creatinine typically preserved. Rarely, AIN with a rising creatinine and, in the reported case, nephrogenic diabetes insipidus.

Management

Manage hyponatremia by addressing the cause and fluid restriction; rarely requires drug interruption. For the rare AIN, withdraw the likely offender(s) and treat supportively. Renal function is generally unaffected.

Risk factors

  • CNS tumor/edema and concurrent SIADH-promoting drugs
  • Nausea/vomiting with hypotonic fluid intake
  • Concomitant trimethoprim-sulfamethoxazole (PJP prophylaxis) as an AIN co-factor
  • Older age

Prevention

  • Avoid unnecessary hypotonic fluids
  • Review co-medications that promote SIADH or AIN

Renal dose adjustment

No renal dose adjustment is established; temozolomide pharmacokinetics are dominated by non-renal chemical degradation. Standard dosing is used across normal-to-mild renal impairment, with caution and limited data in severe impairment/dialysis.

Dialyzability & ESKD dosing

Short half-life with predominantly non-renal (spontaneous hydrolysis) elimination; not a drug managed by dialysis. Limited ESKD data, but renal clearance contributes little to total elimination.

Differential diagnosis

Hyponatremia: SIADH (euvolemic, concentrated urine, natriuresis) vs cerebral salt wasting (hypovolemic, high urine output) - an important CNS-tumor distinction. A rising creatinine should prompt review for AIN from co-medications rather than attribution to temozolomide itself.

Monitoring

  • Periodic serum sodium/electrolytes, especially with SIADH-promoting co-medications
  • Serum creatinine if a new nephrotoxin (e.g., TMP-SMX) is co-prescribed
  • CBC (myelosuppression is the dose-limiting toxicity, not renal injury)

Key trials & series

  • Pivotal Stupp glioblastoma regimen (radiotherapy plus concomitant/adjuvant temozolomide) as the principal exposure context
  • Phase I PK trials (Dhodapkar Clin Cancer Res 1997; Brock Cancer Res 1998) showing minor renal elimination

Clinical pearls

  • Temozolomide is genuinely renally safe - myelosuppression, not nephrotoxicity, is the toxicity to watch.
  • When sodium falls in a glioma patient, distinguish SIADH from cerebral salt wasting before restricting fluids.
  • A creatinine bump on temozolomide is more likely from a co-prescribed nephrotoxin (e.g., TMP-SMX) than from the drug.

Anticancer mechanism

Oral imidazotetrazine prodrug that spontaneously hydrolyzes to the active methylating species MTIC, methylating DNA at O6- and N7-guanine; cytotoxicity depends on MGMT status and mismatch repair. Standard of care for glioblastoma and other malignant gliomas, and used in some neuroendocrine tumors.

Guidelines & consensus

Each recommendation below is this atlas's faithful summary of the source, not a quotation from it — follow the PubMed link for the wording the society published. Summaries may be superseded; consult the current full text and individualize to the patient.

  • ADQI (2026) — Conventional cytotoxic chemotherapy-associated nephrotoxicity: consensus report of the 34th Acute Disease Quality Initiative (ADQI) WorkgroupCisplatin is identified as a leading cytotoxic nephrotoxin; the workgroup details preventive measures (adequate isotonic hydration, correction of volume depletion, avoidance of concurrent nephrotoxins, attention to electrolyte/magnesium wasting) and management of cisplatin-associated AKI, with a research agenda for knowledge gaps.Kidney Int · PMID 41881107
  • ADQI (2026) — The nephrotoxic effects of anti-cancer therapies: consensus report of the 34th Acute Disease Quality Initiative workgroupProvides expert-based statements (modified Delphi) on preventing and managing cisplatin/platinum-associated AKI, including isotonic IV hydration, attention to volume status and concomitant nephrotoxins, and incorporates evidence that IV magnesium supplementation may reduce cisplatin-associated AKI; emphasizes risk stratification and standardized AKI definitions.Nat Rev Nephrol · PMID 41361704
  • SIRM (2022) — SIRM-SIN-AIOM: appropriateness criteria for evaluation and prevention of renal damage in the patient undergoing contrast medium examinations-consensus statements from Italian College of Radiology (SIRM), Italian College of Nephrology (SIN) and Italian Association of Medical Oncology (AIOM)Recommends eGFR-based renal risk assessment and pre/post-contrast isotonic saline or sodium bicarbonate hydration; advises maintaining a 5-7 day interval between iodinated contrast administration and cisplatin in cancer patients to reduce additive nephrotoxicity.Radiol Med · PMID 35303246
  • KDIGO (2020) — KDIGO Controversies Conference on onco-nephrology: understanding kidney impairment and solid-organ malignancies, and managing kidney cancerIdentifies platinum compounds (especially cisplatin) as leading cytotoxic causes of acute tubular injury, AKI, and electrolyte/magnesium wasting; calls for interdisciplinary onco-nephrology care, accurate GFR estimation, and individualized drug dosing in patients with reduced kidney function.Kidney Int · PMID 33126977
  • KDIGO (2020) — KDIGO Controversies Conference on onco-nephrology: kidney disease in hematological malignancies and the burden of cancer after kidney transplantationAddresses chemotherapy-associated AKI/CKD in hematologic cancer, GFR estimation and chemotherapy dosing in patients with reduced kidney function, and management priorities and research gaps for onco-nephrology care.Kidney Int · PMID 33276867
  • ADDIKD (2025) — Integrating International Consensus Guidelines for Anticancer Drug Dosing in Kidney Dysfunction (ADDIKD) into everyday practiceProvides GRADE-based, drug-specific dose-adjustment recommendations for anticancer agents in kidney dysfunction (illustrated for methotrexate, cisplatin, carboplatin and nivolumab); the recommendations build on Part 1's standardised CKD-EPI eGFR assessment rather than Cockcroft-Gault creatinine clearance.EClinicalMedicine · PMID 40290844
  • ADDIKD (2025) — Aligning kidney function assessment in patients with cancer to global practices in internal medicineThree consensus recommendations: assess kidney function by GFR (measured GFR or CKD-EPI eGFR), classify it using KDIGO categories, and use this uniform approach to dose anticancer drugs — moving cancer medicine away from Cockcroft-Gault estimated creatinine clearance.EClinicalMedicine · PMID 40290845
  • ADDIKD (2025) — A methodology for determining dosing recommendations for anticancer drugs in patients with reduced kidney functionEstablishes that, where RCT evidence is lacking, anticancer drug dosing recommendations in kidney dysfunction should be derived by critically appraising observational literature via GRADE combined with structured international multidisciplinary consensus voting.EClinicalMedicine · PMID 40290846
  • KDIGO (2013) — Diagnosis, evaluation, and management of acute kidney injury: a KDIGO summary (Part 1)Defines/stages AKI by serum creatinine and urine output; emphasizes avoiding nephrotoxins, maintaining euvolemia/perfusion, dose-adjusting drugs to kidney function, and monitoring high-risk patients — the framework applied to nephrotoxic anti-cancer agents.Crit Care · PMID 23394211
  • KDIGO (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease: known knowns and known unknownsEvaluate and risk-stratify CKD, manage to delay progression and its complications, and practise explicit medication management and drug stewardship — the framework the atlas's G1–G5 eGFR banding and every renal dose-adjustment recommendation sit inside. Because the guideline excludes dialysis and transplant recipients by its own statement of scope, its recommendations do not carry to those settings, where this atlas's dialyzability and post-transplant guidance rests on other sources.Kidney Int · PMID 38519239
  • KDIGO (2021) — Executive summary of the KDIGO 2021 Guideline for the Management of Glomerular DiseasesProvides the staging/treatment framework for drug-associated glomerular lesions (e.g., bisphosphonate- and interferon-related collapsing FSGS, VEGF-inhibitor podocytopathy/proteinuria), including immunosuppression and supportive RAAS-blockade strategies.Kidney Int · PMID 34556300
  • KDIGO (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Management of ANCA-Associated VasculitisUpdates immunosuppressive induction (rituximab/cyclophosphamide), incorporates avacopan and lower-dose or glucocorticoid-sparing regimens — the management framework for drug- and checkpoint-inhibitor-associated ANCA/pauci-immune glomerulonephritis.Kidney Int · PMID 38388147
  • KDIGO (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Management of Lupus NephritisUpdates first-line lupus nephritis therapy to combination immunosuppression with the addition of belimumab or a calcineurin inhibitor (voclosporin) — informs management of immune-complex/lupus-like glomerulonephritis encountered with immunotherapy.Kidney Int · PMID 38182299
  • KDIGO (2025) — Executive summary of the KDIGO 2025 Clinical Practice Guideline for the Management of Immunoglobulin A Nephropathy (IgAN) and Immunoglobulin A Vasculitis (IgAV)Encourages liberal kidney biopsy and stricter proteinuria control (<0.5 g/d, ideally <0.3 g/d) with RAAS blockers, SGLT2 inhibitors, and targeted-release budesonide — the framework for IgA-dominant glomerular lesions, including those triggered by immune-modulating cancer therapy.Kidney Int · PMID 40975525

References

6 peer-reviewed references. Citation metadata via PubMed / NLM.

  1. 1.Acute interstitial nephritis and nephrogenic diabetes insipidus following treatment with sulfamethoxazole-trimethoprim and temozolomide.Athavale A et al. · Nephrology (Carlton) · 2020 · PMID 32935422
  2. 2.Toxicity and efficacy of protracted low dose temozolomide for the treatment of low grade gliomas.Pouratian N et al. · J Neurooncol · 2006 · PMID 17082887
  3. 3.Phase I trial of temozolomide (NSC 362856) in patients with advanced cancer.Dhodapkar M et al. · Clin Cancer Res · 1997 · PMID 9815788
  4. 4.Phase I trial of temozolomide using an extended continuous oral schedule.Brock CS et al. · Cancer Res · 1998 · PMID 9766665
  5. 5.Conventional Chemotherapy Nephrotoxicity.Gupta S et al. · Adv Chronic Kidney Dis · 2021 · PMID 35190107
  6. 6.Anticancer drug-induced kidney disorders.Kintzel PE · Drug Saf · 2001 · PMID 11219485

Case reports & series (3)

The weakest rung of clinical evidence — single-patient and small-series reports, strongest first. Each carries a heuristic strength grade (A Strong / B Moderate / C Limited) inferred from its abstract and journal, not a formal appraisal. Weigh well below the primary references above.

  1. C1.[B · Moderate]Central diabetes insipidus induced by temozolomide: A report of two cases.Mahiat C et al. · J Oncol Pharm Pract · 2021 · PMID 32990192
  2. C2.[C · Limited]Central diabetes insipidus: a previously unreported side effect of temozolomide.Faje AT et al. · J Clin Endocrinol Metab · 2013 · PMID 23928668
  3. C3.[C · Limited]Nephrogenic Diabetes Insipidus Associated with Temozolomide Therapy in a Patient with Grade IV Astrocytoma.Fargouche Z et al. · Eur J Case Rep Intern Med · 2025 · PMID 40502960
Educational monograph from NephTox (nephtox.com). Not medical advice — verify against current guidelines before any clinical decision.