Patienter med hjertesygdomme, såsom angina, kongestivt hjertesvigt eller arytmier, bør nøje observeres for forværring af deres kliniske tilstand under behandling med AVONEX.
Patients with cardiac disease, such as angina, congestive heart failure or arrhythmia, should be closely monitored for worsening of their clinical condition during treatment with AVONEX.