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Alkylator

Melphalan

Alkeran · Mel

Alkylator · approved 1964 · 7 references

The myeloma workhorse whose high-dose conditioning can quietly drop the serum sodium.

Signature injury
SIADH / Hyponatremia
Severity
Mild
Reversibility
Reversible
Onset
Days after high-dose administration.

Signature kidney injury & incidence

SIADH / Hyponatremia.

High-dose intravenous melphalan can cause hyponatremia/SIADH; in a small high-dose series most patients showed declining sodium, but this is reported at case/series level rather than as a large quantified rate. Melphalan PK is not adversely affected by renal failure, so transplant in renal impairment is feasible.

Source: Greenbaum-Lefkoe et al., Cancer 1985

Reported injury signatures: SIADH / Hyponatremia, Electrolyte Disturbance.

Renal toxicity profile

  1. SIADH / HyponatremiaPrimarySIADH with hyponatremia and inappropriate urinary sodium loss reported after high-dose IV bolus melphalan (both patients at 2 mg/kg; falling serum Na in 7/10 at 1 mg/kg).
  2. Electrolyte DisturbanceSecondary~35%Hyponatremia in 12/34 (35%) after high-dose melphalan, coinciding with diarrhea ~day 10-12 (attributed to GI losses, not SIADH).

Onset timing & rechallenge

Acute (~1–7 days) — Days after high-dose administration.

Mechanism of kidney injury

High-dose bolus melphalan can precipitate inappropriate antidiuretic hormone secretion with free-water retention and dilutional hyponatremia; conditioning-related mucositis and diarrhea cause additional volume and sodium disturbances (some hyponatremia is GI-loss rather than true SIADH). Melphalan is partly renally cleared, so impaired kidney function raises systemic and mucosal toxicity and motivates dose reduction (e.g., 200 to 140 mg/m2) in renal failure/amyloidosis.

Clinical presentation

Hyponatremia with inappropriately concentrated urine and ongoing natriuresis (SIADH pattern); in the conditioning setting, accompanying mucositis, diarrhea and volume shifts. Direct tubular nephrotoxicity is not characteristic.

Management

Manage SIADH with fluid restriction and careful, rate-limited sodium correction; treat volume and electrolyte derangements supportively. Hyponatremia typically resolves as the acute effect and mucositis abate.

Risk factors

  • High-dose / bolus IV administration (conditioning)
  • Renal impairment (reduced clearance, greater mucosal toxicity)
  • Concurrent hypotonic fluids
  • Mucositis/diarrhea-related volume loss

Prevention

  • Avoid excess hypotonic fluids
  • Dose-reduce (e.g., 140 mg/m2) and monitor in renal impairment / amyloidosis

Renal dose adjustment

For high-dose conditioning, 140 mg/m2 is commonly used as a conservative dose in significant renal impairment / dialysis dependence and in AL amyloidosis. Melphalan pharmacokinetics are NOT adversely affected by impaired renal function (Tricot), so renal impairment is not itself a barrier to high-dose conditioning; that study nonetheless found renal insufficiency associated with longer fever and hospitalization, and the same group later reported that the more pronounced toxicity of the 200 mg/m2 regimen is why 140 mg/m2 became the standard of care.

Dialyzability & ESKD dosing

Melphalan is short-lived (rapid chemical hydrolysis) so it is not reliably removed by dialysis as a rescue; however, high-dose autotransplant has been performed safely in dialysis-dependent patients using the reduced 140 mg/m2 dose with attention to mucositis.

Differential diagnosis

Euvolemic hyponatremia with concentrated urine and natriuresis points to SIADH; hypovolemic hyponatremia with low urine sodium and clinical volume loss points to mucositis/diarrhea-driven depletion. The distinction changes management (fluid restriction vs cautious repletion).

Monitoring

  • Serum sodium and fluid balance during/after high-dose therapy
  • Mucositis severity and volume status (diarrhea-related hyponatremia)

Key trials & series

  • Greenbaum-Lefkoe Cancer 1985 - original SIADH/hyponatremia description after high-dose IV melphalan
  • Tricot Clin Cancer Res 1996 - PK/toxicity of high-dose melphalan autotransplant in renal failure
  • Sanchorawala Bone Marrow Transplant 2001 - HDM/SCT in AL amyloidosis with renal involvement

Clinical pearls

  • Check sodium after high-dose melphalan - SIADH is the signature renal-electrolyte event, not tubular injury.
  • Renal failure is NOT a contraindication to high-dose melphalan transplant; reduce to 140 mg/m2 and watch mucositis.
  • Not all post-conditioning hyponatremia is SIADH - GI losses from mucositis/diarrhea are a common, differently managed cause.

Anticancer mechanism

Phenylalanine-mustard bifunctional alkylating agent that cross-links DNA. Backbone of multiple myeloma therapy and the standard high-dose conditioning agent before autologous stem cell transplant; also used in light-chain (AL) amyloidosis and (regional perfusion) melanoma.

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

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

  1. 1.Syndrome of inappropriate antidiuretic hormone secretion. A complication of high-dose intravenous melphalan.Greenbaum-Lefkoe B et al. · Cancer · 1985 · PMID 3965085
  2. 2.L-phenylalanine mustard-dianhydrogalactitol and hyponatremia.Helson L et al. · Pediatr Hematol Oncol · 1986 · PMID 3153241
  3. 3.Safety of autotransplants with high-dose melphalan in renal failure: a pharmacokinetic and toxicity study.Tricot G et al. · Clin Cancer Res · 1996 · PMID 9816255
  4. 4.High-dose therapy in patients with plasma cell dyscrasias and renal dysfunction.Pineda-Roman M et al. · Contrib Nephrol · 2007 · PMID 17075230
  5. 5.An overview of the use of high-dose melphalan with autologous stem cell transplantation for the treatment of AL amyloidosis.Sanchorawala V et al. · Bone Marrow Transplant · 2001 · PMID 11704785
  6. 6.Advances in biology and therapy of multiple myeloma.Barille-Nion S et al. · Hematology Am Soc Hematol Educ Program · 2003 · PMID 14633785
  7. 7.Anticancer drug-induced kidney disorders.Kintzel PE · Drug Saf · 2001 · PMID 11219485

Case reports & series (1)

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.[C · Limited]Transplant-Associated Thrombotic Microangiopathy After Autologous Hematopoietic Stem Cell Transplantation Treated With Eculizumab.Tokura T et al. · Cureus · 2025 · PMID 40717883
Educational monograph from NephTox (nephtox.com). Not medical advice — verify against current guidelines before any clinical decision.