Calan SR warnings and precautions include being aware of potential drug interactions, the safety of taking the medication when pregnant or breastfeeding, and the risk of taking the drug if you have congestive heart failure. People with liver disease or heart disease should talk to their doctor before taking the drug. You should not take Calan SR if you are allergic to any ingredients in the medication or if you have severe left ventricular dysfunction.
Any allergies, including allergies to food, dyes, or preservatives.
Also, let your healthcare provider know if you are:
Pregnant or thinking of becoming pregnant
Breastfeeding.
Make sure to tell your healthcare provider about any other medicines you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.