Some of these side effects may occur when taking this medication; they are as follows; Constipation, nausea, headache, diarrhea, vomiting, stomach upset, gas, tremor, dizziness, drowsiness, or trouble sleeping may occur. However if any of these effects persist or worsen, contact your doctor right away.
Tell your doctor right away if you have any serious side effects, including: unusual tiredness, fast/irregular heartbeat, easy bleeding/bruising, swelling of the feet or ankles.
Get medical help right away if you have any very serious side effects, including: stomach/abdominal pain that doesn't go away, black stools, vomit that looks like coffee grounds, chest pain, shortness of breath/rapid breathing.
This medication may increase your risk of getting a rare but very serious (possibly fatal) brain infection (progressive multifocal leukoencephalopathy-PML). Get medical help right away if you have any of these side effects: clumsiness, loss of coordination/balance, weakness, sudden change in your thinking (such as confusion, difficulty concentrating, memory loss), difficulty talking/walking, seizure, vision changes.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.