Headache, nausea, vomiting, diarrhea, abdominal pain, heartburn, and dizziness may occur. Talk with your doctor if you have a severe headache when you first start taking this medication. Your doctor may change your dose for the first week to lessen headache (see also How to Use section). If any of these effects last or get worse, tell your doctor or pharmacist promptly.
To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including: easy bleeding/bruising, uncontrolled bleeding from gums or nose, fast/slow/irregular heartbeat, loss of appetite, dark urine, yellowing eyes/skin, unusual tiredness, unusual weakness, signs of kidney problems (such as change in the amount of urine).
This drug may rarely cause serious bleeding from the stomach or intestines. If you notice any of the following serious side effects, stop taking this medication and consult your doctor or pharmacist right away: stomach/abdominal pain that doesn't go away, black stools, vomit that looks like coffee grounds.
Get medical help right away if you have any very serious side effects, including: fainting, symptoms of a heart attack (such as chest/jaw/left arm pain, shortness of breath, unusual sweating), signs of bleeding in the brain or stroke (such as weakness on one side of the body, trouble speaking, sudden vision changes, confusion).
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: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.