Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as agitation, hallucinations, confusion), difficulty urinating, vision changes, slow/fast heartbeat, severe stomach/abdominal pain, change in the amount of urine.
Get medical help right away if you have any very serious side effects, including: slow/shallow breathing, fainting, seizures.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.