Ester-C

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

You should not use ascorbic acid if you have ever had an allergic reaction to a vitamin C supplement.

Ask a doctor or pharmacist about using ascorbic acid if you have:

• kidney disease or a history of kidney stones;

• hereditary iron overload disorder (hematochromatosis); or

• if you smoke (smoking can make ascorbic acid less effective).

Your dose needs may be different during pregnancy or while you are breast-feeding a baby. Do not use ascorbic acid without your doctor's advice in either case.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using ascorbic acid and call your doctor at once if you have:

• joint pain, weakness or tired feeling, weight loss, stomach pain;

• chills, fever, increased urge to urinate, painful or difficult urination; or

• severe pain in your side or lower back, blood in your urine.

Common side effects may include:

• heartburn, upset stomach; or

• nausea, diarrhea, stomach cramps.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Other drugs may interact with ascorbic acid, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Applies to ascorbic acid: compounding powder, injectable solution, oral capsule, oral gum, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating, oral tablet extended release

Renal

Renal side effects have included oxalate and urate kidney stones.[Ref]

Hyperoxaluria appears to be dose-related.[Ref]

Nervous system

Migraine headache has been reported with a daily dose of 6 grams.

The manufacturer reports temporary dizziness and faintness may be associated with too rapid of a rate during intravenous administration.[Ref]

Nervous system side effects have included dizziness, faintness, fatigue, and headache in less than 1% of patients. Migraine headache has also been reported.[Ref]

Other

Conditional scurvy is reported to occur following excessive doses of ascorbic acid (the active ingredient contained in Ester-C) over a prolonged period of time. The mechanism of action for this condition is thought to be that large doses of ascorbic acid condition the patient over time for rapid clearance of ascorbic acid resulting in scurvy. The plasma levels of ascorbic acid appear to remain within normal limits. The actual existence of conditional scurvy remains controversial.[Ref]

Other side effects have included flank pain in less than 1% of patients. Conditional scurvy has also been reported.[Ref]

Gastrointestinal

Gastrointestinal side effects have included nausea, diarrhea, abdominal cramps, and esophagitis.[Ref]

Nausea, diarrhea, and abdominal cramps appears to be associated with doses exceeding 2 g per day, although there have been some reports with as little as 1 g per day.

Esophagitis appears to be associated with prolonged or increased contact of ascorbic acid tablets with the esophageal mucosa.[Ref]

Hematologic

The majority of hemolysis reports have been associated with patients who have concurrent glucose-6-phosphate dehydrogenase deficiency.[Ref]

Hematologic side effects have included hemolysis.[Ref]

Local

Local side effects have included transient mild soreness at the site of injection.[Ref]

Some side effects of Ester-C may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.