Make sure your doctor knows if you are pregnant or breastfeeding, or if you have lung disease, heart rhythm problems (slow heartbeat), or low blood pressure.
Tell your doctor right away if you have bluish lips or skin; chest pain; difficulty with breathing; a fast, pounding, or irregular heartbeat or pulse; shortness of breath; or muscle stiffness after receiving this medicine.
Dizziness, lightheadedness, or fainting may occur with this medicine, especially when you get up from a lying or sitting position suddenly. Getting up slowly may help. If this continues or gets worse, check with your doctor.
This medicine may cause constipation. This is more common if you use it for a long time. Ask your doctor if you should also use a laxative to prevent and treat constipation.