Quetiapine and cardiac muscle disorders.

Several detailed case reports have described cardiac muscle disorders (cardiomyopathy and myocarditis) in patients treated with quetiapine, some of which have been fatal. The symptoms included shortness of breath and oedema. The disorders sometimes resolved on withdrawal of quetiapine. Quetiapine is chemically similar to clozapine and olanzapine, which are known to sometimes provoke this type of adverse effect. In practice, a patient who develops dyspnoea or other signs of heart failure during quetiapine therapy may benefit if the drug's role is recognised and quetiapine withdrawn.