Side Effects of This Medicine

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, they may be more likely to occur if caffeine is taken in large doses or more often than recommended. If they do occur, they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

More common

Diarrhea; dizziness; fast heartbeat; hyperglycemia, including blurred vision, drowsiness, dry mouth, flushed dry skin, fruit-like breath odor, increased urination, ketones in urine, loss of appetite, nausea, stomachache, tiredness, troubled breathing, unusual thirst, or vomiting (in newborn babies); hypoglycemia, including anxious feeling, blurred vision, cold sweats, confusion, cool pale skin, drowsiness, excessive hunger, fast heartbeat, nausea, nervousness, restless sleep, shakiness, or unusual tiredness or weakness (in newborn babies); irritability, nervousness, or severe jitters (in newborn babies); nausea (severe); tremors; trouble in sleeping; vomiting

Rare

Abdominal or stomach bloating; dehydration; diarrhea (bloody); unusual tiredness or weakness

Symptoms of overdose

Abdominal or stomach pain; agitation, anxiety, excitement, or restlessness; confusion or delirium; convulsions (seizures)—in acute overdose; dehydration; faster breathing rate; fast or irregular heartbeat; fever; frequent urination; headache; increased sensitivity to touch or pain; irritability; muscle trembling or twitching; nausea and vomiting, sometimes with blood; overextending the body with head and heels bent backward and body bowed forward; painful, swollen abdomen or vomiting (in newborn babies); ringing or other sounds in ears; seeing flashes of “zig-zag” lights; trouble in sleeping; whole-body tremors (in newborn babies)

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Nausea (mild); nervousness or jitters (mild)

After you stop using this medicine, your body may need time to adjust. The length of time this takes depends on the amount of medicine you were using and how long you used it. During this time, check with your doctor if you notice any of the following side effects:

More common

Anxiety; dizziness; headache; irritability; muscle tension; nausea; nervousness; stuffy nose; unusual tiredness

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.