INTRODUCTION: For more than 50 years the acetylcholinesterase inhibitor 
pyridostigmine bromide has been the drug of choice in the symptomatic therapy 
for myasthenia gravis. The sustained-release dosage form of pyridostigmine 
(SR-Pyr) is only available in a limited number of countries (e.g. in the United 
States and Germany). Astonishingly, the therapeutic usefulness of SR-Pyr has not 
yet been evaluated.
METHODS: In this non-interventional prospective open-label trial, 72 patients 
with stable myasthenia gravis were switched from instant-release dosage forms of 
pyridostigmine bromide to SR-Pyr. The results from the 37 patients younger than 
60 years were separately analyzed.
RESULTS: The initial daily dose of SR-Pyr was 288.1 ± 171.0mg. The drug switch 
was unproblematic in all patients. The number of daily doses was significantly 
reduced from 4.3 to 3.6 (p=0.011). The switch to SR-Pyr ameliorated the total 
quantified myasthenia gravis (QMG) score from 0.9 ± 0.5 to 0.6 ± 0.4 (p<0.001) 
in all patients and in the younger subgroup. This was accompanied by a 
significant improvement in the quality of life parameters. The health status 
valued by EuroQoL questionnaire improved from 0.626 ± 0.286 to 0.782 ± 0.186 
(p<0.001). After switching to SR-Pyr, 28 adverse reactions disappeared and 24 
adverse reactions occurred less frequent or weaker, however, 17 new adverse 
reactions were documented.
CONCLUSIONS: Our results support the usefulness of SR-Pyr in an individualized 
therapeutic regimen to improve quality of life regardless of the patient's age 
in myasthenia gravis.