Bronchoconstriction in response to suggestion: its prevention by an inhaled anticholinergic agent.

frequent development of tachyphylaxis apart from numerous other toxic reactions and the painfulness of the injections. The main advantage of dimercaprol is that the molecule is not charged, is soluble in lipids, and is able to cross the blood-brain barrier fairly easily compared with penicillamine, trientine dihydrochloride, and unithiol, which are highly charged. Treatment with unithiol was started in two other patients. The first developed a fever of 39"C four hours after the test dose and a 50°, fall in the leucocyte count. A further challenge dose caused a similar reaction and treatment was not pursued. This patient was subsequently managed with tetrathiomolybdate.3 The second patient took unithiol for 10 days before refusing it because of intense nausea and a change in taste. Other patients have received single test doses, and the resulting cupruresis has been comparable with that after penicillamine and trientine dihydrochloride in most cases. Unithiol may well prove to be yet one more fall back treatment for patients who develop intolerance to penicillamine.