TOXICOLOGICAL PROFILE FOR BARIUM AND COMPOUNDS ...

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2. HEALTH EFFECTS
Other medically prescribed drugs interact with barium. Experiments with
mice indicated that atropine significantly antagonized antinociception and
death induced by intracerebroventricular injection of barium chloride (Segreti
et al. 1979; Welch et al. 1983). These same studies also found that naloxone,
a narcotic antagonist, inhibited the lethal toxicity of barium (Segreti et al.
1979; Welch et al. 1983). Propranolol had no effect 'on barium-induced
paralysis in rats (Schott and McArdle 1974). Verapamil rapidly abolished
cardiac dysrhythmias in rabbits injected with barium chloride (Mattila et
al. 1986). In the same study, pretreatment with the tricyclic antidepressant,
doxepin, was found to offer some protection against barium-induced
dysrhythmias (Mattila et al. 1986). Cuabain which is an inhibitor of Na + -K +
ATPase, while not widely prescribed, has been shown to rapidly reverse the
paralyzing effects of barium. it has been hypothesized that ouabain works by
reducing barium-induced hypokalemia thereby allowing some intracellular
potassium to escape. However, this hypothesis has not yet been proved or
disproved because of the complexity of the mechanism involved (Schott and
McArdle 1974).
Other substances can affect barium pharmacokinetics. One study showed
that sodium alginate could reduce retention of orally administered barium,
possibly by inhibiting reabsorption in the gut (Sutton et al. 1972). This
could be useful in treating cases of acute barium ingestion. Lysine and
lactose increase absorption of barium and could increase the toxic effects of
oral exposure (Lengemann 1959).
A human study involving one adult female was performed by applying
barium chloride, alone and in combination, with dimethyl sulfoxide to the
cervical epithelium. Dimethyl sulfoxide significantly enhanced the ability of
barium chloride to induce dysplasia with unusual cell formation in the
cervical epithelium (Ayre 1966). The significance of this is difficult to
determine since there was only one subject, there were no controls, and few
details of the experiment were provided.
2.7 POPULATIONS THAT ARE UNUSUALLY SUSCEPTIBLE
The limited data available suggest that certain subgroups of the
population may be more susceptible to barium exposure than the general
population. These include people with cardiovascular problems, those taking
certain prescription drugs, children, pregnant women, smokers, and people with
lung disease.
A consistent toxic effect of barium in humans and animals is increased
blood pressure. Therefore, humans with hypertension could be at increased
risk from either chronic, intermediate, or acute barium exposure. In
addition, the cardiotoxic effects of barium exposure could increase the risk
for those individuals suffering from other heart problems.