trans

FURTHER READING 461
The excitement engendered by these
advances must be tempered by the realities of
drug development and production. The first
hurdle is drug toxicity. At times predictable,
but often idiosyncratic, unexpected untoward
effects have prevented the use of many otherwise
effective anti-parasitic drugs. Particularly
troublesome are serious toxicities that occur
at low frequency. They may come to attention
only after a drug has been marketed.
To be successful, new drugs must also have
favorable pharmacodynamics. Oral administration
in a single dose or several doses on one
day is particularly important for mass treatment
programs in areas where the lack of education,
refrigeration and other logistic factors
may interfere with compliance.
The economic realities of new drug development
must also be considered. Many parasitic
diseases are endemic in impoverished
areas where the likelihood of profits is too
small to engender investment by major pharmaceutical
companies. Even if a highly effective
anti-parasitic drug is identified, the cost of
development may be prohibitive.
The cost of production is also critical as
illustrated by eflornithine. It seems tragic that
the manufacture of an effective anti-parasitic
drugs should cease for economic reasons at a
time when the drug is critically needed. The
story can be different for drugs that are used in
industrialized countries for other human indications
or veterinary infections. As illustrated
by ivermectin, which is marketed for the treatment
of the dog heartworm, Dirofilaria immitis,
veterinary use and profits have offset production
costs. Ivermectin has been donated
by the manufacturer for the treatment of
onchocerciasis.
There are no simple answers to the economic
constraints on basic research, drug development
and production. There is increasing realization
that health is an issue of international
security. The World Health Organization, World
Bank, National Institutes of Health, Gates
Foundation and other governmental and
non-governmental groups have increasingly
focused their resources on diseases of the nonindustrialized
world. Their continued support is
critical to the development, production and
distribution of new anti-parasitic drugs. The
future seems bright, but it will take a concerted
effort to bring the fruits of modern science to
the bedside of the poor who suffer from parasitic
diseases.
FURTHER READING
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MEDICAL APPLICATIONS