Trivalent Antimony Compounds
Antimony potassium Tartrate
Odourless, colourless, transparent crystals or white powder.
The crystals effloresce on exposure to air and do not readily
rehydrate even when exposed to high humidity.
Soluble I in 12 of water. I in 3 of boiling water, and I in 15
of glycerol: practically insoluble in alcohol. Solutions in wa-
ter are acid to litmus.
Incompatible with acids and alkalis, salts of heavy metals.
albumin, soap, and tannins.
Antimony Sodium Tartrate
Odourless, colourless, transparent crystals or white powder.
The crystals effloresce on exposure to air.
Freely soluble in water: practically insoluble in alcohol. In-
compatible with acids and alkalis, salts of heavy metals, al-
bumin, soap, and tannins.
Adverse Effects and Treatment
Trivalent antimony compounds are more toxic than pentava-
lent antimonials such as sodium stibogluconate. possibly be-
cause they are excreted much more slowly. The most serious
adverse effects arc on the heart and liver. There arc invariably
ECG changes during treatment, but hypotension, bradycar-
dia. and cardiac arrhythmias are more serious. Sudden death
or cardiovascular collapse may occur at any time. Elevated
liver enzyme values are common; liver damage with hepatic
failure and death is most likely in patients with pre-existing
hepatic disease.
Adverse effects immediately after intravenous administration
of trivalent antimonials, in particular the tartrates. have in-
cluded coughing, chest pain, pain in the arms, vomiting, ab-
dominal pain, fainting, and collapse, especially after rapid
injection. Extravasation during injection is extremely painful
because of tissue damage. An anaphylactoid reaction charac-
terised by an urticarial rash, husky voice, and collapse has
been reported after the sixth or seventh intravenous injection
of a course of treatment.
Numerous less immediate adverse effects have occurred in-
cluding gastro-intestinal disturbances, muscular and joint
pains, arthritis, pneumonia, dyspnoea, headache, dizziness,
weakness, pruritus, skin rashes, facial oedema, fever, haemo-
lytic anaemia, and kidney damage.
Large doses of antimony compounds taken by mouth have an
emetic action. Continuous treatment with small doses of anti-
mony may give rise to symptoms of subacute poisoning sim-
ilar to those of chronic arsenical poisoning.
Treatment of severe poisoning with antimony compounds is
similar to that for arsenic poisoning ; dimercaprol
may be of benefit.
Precautions
Trivalent antimony therapy has generally been superseded by
less toxic treatment. It is contra-indicated in the presence of
lung. heart, liver, and kidney disease. Intravenous injections
should be administered very slowly and stopped if coughing,
vomiting, or substernal pain occurs; extravasation should be
avoided.
Some antimony compounds such as the tartrates cause severe
pain and tissue necrosis and should not be given by intramus-
cular or subcutaneous injection.
In the event of trivalent antimony compounds being used then
patients with glucose-6-phosphate dehydrogenase deficiency
should be excluded. WHO lists stibophen among the an-
thelmintics to be avoided in patients with this deficiency.
Pharmacokinetics
Antimony compounds are poorly absorbed from the gastro-
intestinal tract.
They are slowly excreted, mainly in the urine, following
parenteral administration. Antimony accumulates in the body
during treatment and persists for several months afterwards.
Trivalent antimony has a greater affinity for cell proteins than
for plasma proteins.
Uses and Administration
Trivalent antimony compounds were used in the treatment of
the protozoal infection leishmaniasis until the advent of the
less toxic pentavalent compounds. They continued to be used
in the treatment of schistosomiasis, but have now been super-
seded by less toxic and more easily administered drugs such
as praziquantel.
Antimony sodium tartrate was formerly used as an emetic and
expectorant.