Respiratory failure in lambert-eaton myasthenic syndrome precipitated by calcium-channel blockers: report of a case and literature review.

There have been a few reports in the literature documenting the effects of calcium-channel blockers in Lambert-Eaton myasthenic syndrome (LEMS). We report a case of a patient with LEMS who developed respiratory failure after administration of diltiazem and verapamil. A patient with LEMS, associated with small-cell carcinoma in remission, developed multifocal atrial tachycardia, necessitating the use of diltiazem and verapamil, which led to respiratory failure and intubation 5 days after admission. The patient was taken off all calcium-channel blockers and weaned off the respirator after 6 days. Oral time-release diltiazem was restarted without further exacerbation of LEMS. Most likely the combined use of two different calcium-channel blockers, verapamil and diltiazem, was responsible for this patient's respiratory failure. To date, 5 cases (2 patients with LEMS and 3 with myasthenia gravis) in which cardiac calcium-channel blockers had a definite detrimental effect have been reported.