Influence of calcium antagonist drugs in myasthenia gravis in the elderly

A number of drugs have been reported to cause neuromuscular blockade and/or to increase weakness in myasthenia gravis. We report on two patients, treated with felodipine and nifedipine for arterial hypertension, who presented with an exacerbation of their myasthenia gravis and a myasthenic syndrome or exacerbation of myasthenia gravis, respectively. The mechanism of action of calcium antagonist drugs at the neuromuscular junction is not yet well established, but it could be located at both presynaptic and postsynaptic levels.