Pharmacokinetic studies of ambenonium chloride in patients with myasthenia gravis.

Serum levels of ambenonium chloride (AC) were monitored in 4 myasthenic patients. This determination revealed important intraindividual variations (up to 10-fold) over a period of 24 h. Levels varied considerably between different patients (maximum serum concentration of ambenonium chloride ranged from 0.129 to 0.812 micrograms/ml) and no correlation between the daily dose and the AUC was found. These characteristic properties of ambenonium chloride could explain the erratic pattern of bioavailability observed as well as the difficulty in controlling the disease in some patients.