Chemotherapy-induced peripheral neuropathy  Chemotherapy-induced peripheral neuropathy is a progressive, enduring, and often irreversible condition featuring pain, numbness, tingling and sensitivity to cold in the hands and feet (sometimes progressing to the arms and legs) that afflicts between 30% and 40% of patients undergoing chemotherapy. Though the symptoms are mainly sensory – pain, tingling, numbness and temperature sensitivity – in some cases motor nerves are affected, and occasionally, also, the autonomic nervous system. CIPN often follows the first chemotherapy dose and increases in severity as treatment continues, but this progression usually levels off at completion of treatment. The platinum-based drugs are the exception; with these drugs, sensation may continue to deteriorate for several months after the end of treatment. Some CIPN appears to be irreversible. CIPN disrupts leisure, work, and family relations, and the pain of CIPN is often accompanied by sleep and mood disturbance, fatigue and functional difficulties. A 2007 American Cancer Society study found that most patients did not recall being told to expect CIPN, and doctors monitoring the condition rarely asked how it affects daily living but focused on practical effects such as dexterity and gait. Chemotherapy drugs associated with CIPN include thalidomide, the epothilones such as ixabepilone, the vinca alkaloids vincristine and vinblastine, the taxanes paclitaxel and docetaxel, the proteasome inhibitors such as bortezomib, and the platinum-based drugs cisplatin, oxaliplatin and carboplatin. Whether CIPN arises, and to what degree, is determined by the choice of drug, duration of use, the total amount received and whether the patient already has peripheral neuropathy. It is not known what causes the condition, but microtubule and mitochondrial damage, and leaky blood vessels near nerve cells are some of the possibilities being explored. One of the more promising theories is that chemotherapeutic drugs act by disrupting microtubules of the mitotic spindle during cell division, causing the disruption of microtubule based axonal transport of neurons. Also, the nervous system has programmed cell death pathways that are particularly sensitive to DNA damage induced by many chemotherapeutic agents. Pain can often be helped with drug or other treatment but the numbness is usually resistant to treatment. The anticonvulsant valproate, an effective treatment for diabetic neuropathy, appeared to offer some protection against cisplatin-induced neuropathy in rats.