characterized by black or red-colored urine. This is due to hemolysis, which in turn
leads to sludging in the kidney tubules. From 25 percent to 50 percent of the victims of
black-water fever die.
(4) Quinine causes hemolysis in about 1 in every 2000 people. Quinine can
also cause other blood disorders.
(5) Massive hemolysis followed by kidney failure has occurred in pregnant
women after large doses of quinine. Pregnant women, nearing the time to give birth,
who have shown a sensitivity to quinine or who have ever had tinnitus (characterized by
false sounds in the ears), a hemolytic episode, atrial fibrillation, or optic neuritis should
be warned to stay out of areas where there are strains of P. falciparum treatable only
with quinine. No pregnant woman should ever take quinine.
(6)
The lethal dose of quinine is about 8 gm.
d. Supply. The drug is available as 324-mg quinine sulfate tablets and as 2-ml
ampules of quinine dihydrochloride injection (300-mg per ml).
6-24. PYRIMETHAMINE
a. Uses. Pyrimethamine (Daraprim), if administered for at least 10 weeks, can
produce a suppressive cure of an infection with one of the relapsing malarias.
However, it acts too slowly to be useful in relieving acute attacks. It can be used weekly
for suppressive prophylaxis against malaria and for its sporonticidal effects, which deter
the transmission of the infection from a person who already has malaria. Given
concurrently with quinine sulfate or dapsone or both, it can quickly terminate acute
attacks of chloroquine-resistant falciparum malaria in nonimmune clients and also make
a relapse less likely. Pyrimethamine is also sometimes used in combination with oral
sulfonamides to treat toxoplasmosis (infection with organisms of the genus Toxoplasma,
one of which causes enlargement of the spleen and progressive anemia).
b. Usual Dosage.
(1)
For malarial prophylaxis, one 25-mg tablet is given orally each week to
adults.
(2) For the treatment of resistant Plasmodium falciparum, the drug is
administered orally in a dosage of 25-mg twice daily for three days in combination with
quinine or dapsone.
(3) For the treatment of toxoplasmosis in the adult, the starting dose is 50 to
75-mg daily combined with 1 to 4-grams of a sulfonamide drug (that is, sulfadiazine).
This dosage is continued for 1 to 3 weeks. The dosage may then be reduced to about
one-half that previously given for each drug and continued for an additional 4 to 5
weeks.
MD0913
6-24