The growing number of drugs used to treat various diseases and the growing number of invasive procedures used for diagnosis and
therapy have generated many
iatrogenic diseases. Elderly patients are more likely than the young to react adversely to drugs since the physiological functions of the organs, especially of the kidneys, decrease and pharmacokinetic characteristics altered. In addition, multiple disease states are common in the elderly, and multiple drugs are consequently prescribed. In the present study, adverse effects of so-called "cerebroactive drugs" and "cerebral
vasodilators" are discussed. More than 30 kinds of these drugs are on the market in Japan and are widely prescribed for "chronic
cerebrovascular diseases" and "
dementia syndromes" in the elderly. In contrast, they are rarely used in Western Europe and not on the market in the United States. Among them,
calcium hopantenate was the first of "cerebral activators" and was the most popular. In 1986, however, the first cases of
toxic encephalopathy induced by
calcium hopantenate were reported. It resembled
Reye syndrome, showing
coma, hepatic failure,
lactic acidosis and
hypoglycemia and was frequently fatal. More than 47 victims including 11 fatal cases have been reported since.
Flunarizine, a cerebral
vasodilator, produced high rates of
parkinsonism and depression. Multicenter studies have revealed that these side effects occurred in 10-30% of the elderly patients who had taken it. These symptoms usually appeared several months after
flunarizine was started. Some of the adverse effects of the drugs may be unpredictable and inevitable, but most of them can be prevented or reduced if physicians are more careful with their patients, and drugs and their adverse effects.2