Quinine sulphate is a type of
medicine called an antimalarial. Its
main use is in treating established
malarial infections, though it can
also be used for treating leg cramps.
Malaria is a potentially fatal disease
caused by various types of single-
celled (protozoan) parasites known
as Plasmodium. Plasmodium are
carried by mosquitoes and injected
into the bloodstream during a bite
from an infected mosquito. Once in
the blood, the parasites travel to the
liver, where they multiply. The
parasites are then released back into
the bloodstream where they invade
the red blood cells and multiply
again. An actual attack of malaria
develops when the red blood cells
burst, releasing a mass of parasites
into the bloodstream. The attacks do
not begin until a sufficient number
of blood cells have been infected
with parasites.
Quinine works by attacking the
parasites once they have entered the
red blood cells. It kills the parasites
and prevents them from multiplying
further. It is not fully understood
how it kills the parasites.
Quinine is used to treat falciparum
malaria (the most serious kind,
caused by a type of malaria parasite
called Plasmodium falciparum). It is
also used to treat malaria where the
type of infecting organism is
unknown or caused by mixed types
of Plasmodium. It is not suitable for
the prevention of malaria.
Quinine is also sometimes used to
treat recurrent night-time leg
cramps, for instance in people with
arthritis , diabetes or varicose veins .
It is thought to prevent muscle
cramps by reducing the sensitivity of
muscle cells to stimuli that cause
them to contract, as well as by
prolonging the time it takes for the
muscle to contract. It can take up to
four weeks of taking quinine before
an improvement in leg cramps is
seen. If it hasn't helped after four
weeks then it should be st