Cisplatin cannot tell the difference between the DNA of cancer cells and the DNA of healthy cells. It binds to guanine in any cell it enters, so it also damages normal cells, especially those that divide rapidly. This causes adverse effects (side effects).Common side effects include:
• hair loss, because hair follicle cells divide rapidly
• nausea and vomiting
• damage to the kidneys, which excrete the platinum
• hearing loss and nerve damage
• a weakened immune system, because blood cells are made by rapidly dividing cells in the bone marrowReducing the harm
• Giving the drug in small doses, in cycles with breaks so that healthy cells can recover.
• Giving plenty of fluid to protect the kidneys.
• Targeting the drug at the tumour where possible.
• Developing related platinum drugs, such as carboplatin, with fewer side effects.Weighing benefits against risks. Cisplatin is very effective against some cancers; for example, it has made most cases of testicular cancer curable. Doctors, patients and regulators must weigh this benefit against the risk and severity of the side effects. Where a drug can save a life, serious side effects may be accepted; the same side effects would be unacceptable in a drug for a minor illness. Society has to make this judgement for every drug, using evidence from clinical trials.Example. Explain why hair loss is a side effect but most muscle cells are unaffected. Hair follicle cells divide often, so they replicate their DNA frequently and are damaged when cisplatin blocks replication. Mature muscle cells rarely divide, so blocked replication has little effect on them.
• hair loss, because hair follicle cells divide rapidly
• nausea and vomiting
• damage to the kidneys, which excrete the platinum
• hearing loss and nerve damage
• a weakened immune system, because blood cells are made by rapidly dividing cells in the bone marrowReducing the harm
• Giving the drug in small doses, in cycles with breaks so that healthy cells can recover.
• Giving plenty of fluid to protect the kidneys.
• Targeting the drug at the tumour where possible.
• Developing related platinum drugs, such as carboplatin, with fewer side effects.Weighing benefits against risks. Cisplatin is very effective against some cancers; for example, it has made most cases of testicular cancer curable. Doctors, patients and regulators must weigh this benefit against the risk and severity of the side effects. Where a drug can save a life, serious side effects may be accepted; the same side effects would be unacceptable in a drug for a minor illness. Society has to make this judgement for every drug, using evidence from clinical trials.Example. Explain why hair loss is a side effect but most muscle cells are unaffected. Hair follicle cells divide often, so they replicate their DNA frequently and are damaged when cisplatin blocks replication. Mature muscle cells rarely divide, so blocked replication has little effect on them.