Platinum chemotherapy: kidneys, hearing, nerves, electrolytes and hypersensitivity

How platinum agents work and how they differ

Platinum compounds form cross-links in DNA that stop cancer cells from copying it. Cisplatin and carboplatin share that mechanism but differ in toxicity. Cisplatin causes more kidney damage, nausea, hearing loss and nerve injury. Carboplatin is less harsh on the kidneys and nerves but suppresses bone marrow more strongly and is dosed with kidney function in mind.

The names are similar and the doses very different, so the cisplatin label carries a boxed warning about inadvertent overdose from confusing the two. Nurses independently verify the drug name, dose and calculation with a second checker before administration. Platinum agents are also handled with standard hazardous drug precautions.

Protecting the kidneys during cisplatin

Cisplatin damage to the kidney tubules is cumulative and can be severe. The label requires intravenous hydration before and after the dose and checks of serum creatinine and urea before each cycle. Nurses monitor intake and output, daily weight and urine flow, encourage oral fluids as prescribed, and report low urine output before the next dose rather than after it.

Other nephrotoxic drugs add to the risk. Aminoglycoside antibiotics given with cisplatin increase kidney injury and hearing loss, so the nurse flags the combination and other kidney-stressing drugs to the prescriber. Patients are taught to report reduced urination, swelling or unusual tiredness, which can signal kidney injury between visits.

Hearing, nerves and electrolyte loss

Cisplatin ototoxicity causes ringing in the ears and hearing loss, which can be permanent and is often more pronounced in children. The label calls for audiometric testing before starting and during treatment. Ask about tinnitus, muffled hearing or dizziness at each visit. Peripheral neuropathy causes tingling, burning or numbness in the hands and feet and may be irreversible.

Kidney tubule injury causes wasting of magnesium, potassium and calcium, so cramps, weakness, tremor, tetany or arrhythmias may reflect electrolyte loss. Nurses review electrolyte results, give replacement as prescribed and report low values, particularly in patients on cardiac drugs. Carboplatin labelling also lists frequent abnormalities in sodium, potassium, calcium and magnesium.

Nausea, marrow suppression and hypersensitivity

Cisplatin causes nausea and vomiting in almost all patients without prevention, sometimes lasting days, so antiemetics are given before the dose and continued as prescribed for delayed symptoms. Myelosuppression occurs with both agents and is dose-limiting with carboplatin, so infection and bleeding teaching apply. Carboplatin should not be given with aluminium-containing needles or sets. The cisplatin label places the platelet and white cell low point around the third week after a dose and advises weekly counts, so the risk window often falls between clinic visits.

Both drugs can cause anaphylactic reactions within minutes of starting, with facial swelling, wheeze, low blood pressure and fast heart rate. Carboplatin risk is higher in people previously exposed to platinum. The nurse stays with the patient early in the infusion, keeps emergency medicines available, and if a reaction occurs stops the infusion, supports airway and circulation and calls for help.

Working a hypothetical platinum scenario

Imagine a patient back for a third cisplatin cycle who reports ringing in both ears since the last cycle, and whose morning results show a raised creatinine and low magnesium. The options are to start pre-hydration and give the dose as scheduled, give magnesium and proceed, hold the cisplatin and notify the prescriber, or reassure the patient that tinnitus is temporary.

Holding and notifying the prescriber is the best choice because new tinnitus and rising creatinine suggest cumulative ototoxicity and nephrotoxicity that may change the plan. Proceeding risks permanent harm, replacing magnesium alone treats only one result, and the reassurance is inaccurate because hearing loss can be permanent. This is an invented study example.

Sources and further reading

DailyMed: Cisplatin injection prescribing information. Mechanism, nephrotoxicity and hydration, ototoxicity and audiometry, neuropathy, nausea, myelosuppression, anaphylaxis, aminoglycoside interaction, electrolyte loss and carboplatin confusion warning.

DailyMed: Carboplatin injection prescribing information. Boxed warnings for marrow suppression and anaphylaxis, higher risk with prior platinum exposure, electrolyte abnormalities, renal dosing and aluminium incompatibility.

MedlinePlus: Cisplatin injection. Patient reporting of hearing changes, reduced urination and swelling, neuropathy and allergic reactions.