Neurologic disease/impairment

Neurotoxicity and allergic reactions are rare. Piperazine compounds should not be given to women during pregnancy, to patients with impaired renal or hepatic function, or to those with a history of epilepsy or chronic neurologic disease. 

Free radical formation is an important contributor to cell death and brain injury in many neurological diseases. Shortly after brain damage by hypoxia-ischemia, hemorrhage, or trauma, excessive reactive oxygen species (ROS) production occurs, and at the same time, there is an impairment of antioxidant protective mechanisms, which leads to oxidative stress (Heo et al 2005). 

In many neurodegenerative diseases, neurodegeneration shortens the life expectancy of patients, but other neurodegenerative diseases are fatal per se. Only those diseases in which neurological structures impair ability to control or execute such vital functions as respiration, heart rate, or blood pressure are deadly (Przedborski et al., 2003). Thus, in ALS, loss of lower motor neurons innervating respiratory muscles leads the patient to succumb to respiratory failure. Alternatively,... 

Parenteral administration of iodinated contrast media to patients taking metformin may result in lactic acidosis. However, the problem is reported to occur only if the contrast media causes renal failure and metformin use is continued. This is because metformin is mainly excreted by the kidneys and in renal failure toxic levels may accumulate, which may result in lactic acidosis. A literature search identified 18 cases of lactic acidosis after the use of contrast media in patients taking metformin. Of these 18 cases, 14 or 15 were associated with pre-existing renal impairment and 2 cases with other contraindications to metformin (sepsis and cirrhosis). The remaining case was in an elderly woman with neurological disease. 

Another group of organisms that straddle the life - non-life border are the prions. These have come to public attention recently because of their controversial association with Creutzfeld-Jacob disease (CJD), a fatal infection of the brain in humans, so-called scrapie in sheep, and bovine spongiform encephalopathy (BSE), a related disease in cattle, as discussed by Heaphy (2004) and in Prusiner (2004). Several other neurological diseases in animals and humans are also linked with prions which are proteinaceous particles and thus earbon-based. Unlike other disease-causing organisms, prions do not contain nucleic acids and consist of modified forms of normal cellular protein. They ean be ineubated in brain tissue for long periods before they have an effeet whieh involves impairment of tissue function and ultimately impairment of human/animal funetion prior to death. How prions enter the body and infeet brain tissue has not yet been aseertained in detail. 

When the hydantoins are used with odier CNS depressants (eg, alcohol, narcotic analgesics, and antidepressants), an additive CNS depressant effect may occur. The hydantoins are used cautiously in patients widi liver or kidney disease and neurologic disorders. Phenytoin is used cautiously in patients widi hypotension, severe myocardial insufficiency, and hepatic impairment. 

---