Mercurochrome
Incompatible with acids, most alkaloidal salts, many local
anaesthetics, metals, and sulphides. Activity may be reduced
in the presence of organic material.
Adverse Effects, Treatment, and Precautions
Adverse Effects
Liquid mercury if ingested is poorly absorbed and, unless
there is aspiration or pre-existing gastro-intestinal disorders,
is not considered to be a severe toxicological hazard.
The greatest dangers from liquid mercury arise from the inha-
lation of mercury vapour. On acute exposure, it can cause var-
ious gastro-intestinal effects including nausea, vomiting, and
diarrhoea: more importantly it is toxic to the respiratory sys-
tem and this effect can be fatal. Some CNS involvement has
also been reported. Liquid mercury is not without its dangers
when injected and there have been a number of reports of ac-
cidental or intentional parenteral administration. Inorganic
salts such as mercuric chloride are corrosive when ingested
causing severe nausea, vomiting, pain, bloody diarrhoea, and
necrosis. The kidney is also involved and tubular necrosis
may develop. Mercurous salts are considered to be less haz-
ardous, but the mercurous form can be convened to the mer-
curic.
Chronic mercury poisoning may result-from inhalation of
mercury vapour, skin contact with mercury or mercury com-
pounds, or ingestion of mercury salts over prolonged periods.
It is characterised by many symptoms including tremor, mo-
tor and sensory disturbances, mental deterioration, gastro-in-
testinal symptoms, dermatitis, kidney damage, salivation, and
loosening of teeth. A blue line may be present on the gums.
Poisoning with mercury or inorganic mercury salts has arisen
from a variety of sources such as batteries, cosmetics, dental
materials, medical equipment, and jewellery manufacture.
Barometers, sphygmomanometers. and thermometers are still
sources of liquid mercury. Trace amounts of organic and in-
organic mercury may also be ingested in the diet.
The syndrome of acrodynia (pink disease), with symptoms of
sweat, rash, oedema of the extremities photophobia, wasting,-
weakness, tachycardia, and diminished reflexes, occurred in
children given mercury in teething powders or in ointments or
dusting powders. Such preparations have long since been
withdrawn from use. However, the syndrome is still a feature
of mercury poisoning from other sources.
Organic mercurial compounds produce similar toxic effects
to inorganic compounds, but they have a more selective action
on the CNS that has proved difficult to treat. The degree of
toxicity varies with the different groups of organic mercuri-
als: those used as preservatives or disinfectants being less
toxic than the ethyl or methyl compounds that are not used
pharmaceutically or clinically. Methylmercury is notorious
for its toxicity; there have been cases of fetal neurotoxicity
during outbreaks of methylmercury poisoning. There is little
difference between acute and chronic poisoning with organic
mercurials.
Hypersensitivity to mercury and mercurial compounds has
been reported
Mercurial rash has been reported in patients treated with eye
drops; containing an organomercurial preservative.
Acute occupational exposure to mercury vapour in 53 men
resulted in an initial phase described as metal fume fever, an
imennediate phase of severe symptoms with CNS, gastro-in-
testinal, respiratory, and urological involvement, and a late
phase with persistent CNS symptoms. dysuria. and pain on
ejaculation. Although persistent hyperchloremia was not-
ed in the 11 patients with the highest mercury levels, renal
impairment tended to be temporary. Long-term follow-up of
a patient who had an intravenous injection of mercury 12
years previously also revealed no persistent renal impair-
ment,3 despite the presence of mercury micro emboli in lungs,
kidneys, liver, and subcutaneous tissues and high concentra-
tions in the urine. At this time. the patient had residual
reduc-
tions in respiratory function, polyneuropathy, and marked
asthenozoospermia. Spermatozoal abnormalities may also
have contributed to his wife's miscarriage. Fetal neurotoxicity
following maternal exposure to methylmercury is well recog-
nised, and has been shown to cause delays in neurological de-
velopment in affected children up to the age of 7 years'
There has been considerable concern over the systemic ab-
sorption of mercury from dental amalgam, which typically
contains between 40 and 70% of mercury. However, the quan-
tities absorbed from amalgam fillings is reported to be rela-
tively small and current evidence suggests that the use of
dental amalgam for tooth restoration is both safe and effec-
tive.7Β·8 The main risks appear to be occupational exposure of
dental staff and environmental concerns. Some patients with
hypersensitivity to mercury may benefit from removal of
amalgam fillings
The symptoms of acrodynia have been mistaken for those of
pheochromocytoma.
Treatment of Adverse Effects
Ingestion of liquid mercury seldom requires active treatment.
Acute poisoning due to other inorganic mercury sources
should be treated if appropriate by immediate emesis or gas-
tric lavage; a 5% solution of sodium formaldehyde sulphoxy-
late may be used with the aim of converting the mercuric form
to the mercurous. Large quantities of milk or charcoal may
also be given. Dimercaprol therapy should be
started immediately. Other chelating agents that may be used
include penicillamine , succimer , or unithiol .
Some centres institute haemodialysis at the beginning of
treatment; others wait until renal failure develops when either
haemodialysis or peritoneal dialysis is used.
Symptomatic measures should be used to alleviate the poten-
tially wide range of toxic effects.
Mercurials on the skin should be removed by copious wash-
ing with soap and water.
Poisoning due to organic mercury is difficult to treat. The
same measures as above should be adopted, except that it is
recommended by some that dimercaprol should not be used
since animal evidence indicates that it may increase the
brain concentrations of mercury. An additional measure that has
been tried is the administration of a resin complex to prevent
the reabsorption of mercury from the bile.
Reports of mercurochrome toxicity have included contact
dermatitis' and epidermal cell toxicity. A fatality has oc-
curred following transcutaneous absorption of mercuro-
chrome during treatment of infected omphalocele (umbilical
hernia) and death due to shock, with aplastic anaemia, has
followed application to surgical wounds and decubitus ulcer.
Extensive absorption following ingestion has also been re-
ported.
Uses and Administration
Mercurochrome is a mercurial antiseptic that has been used
for disinfection of skin and wounds.