This medication is used to treat a wide variety of bacterial infections. It is also used to prevent infection of the heart (bacterial endocarditis) in patients with certain heart diseases who are having surgery. This medication is known as a natural penicillin antibiotic. It works by stopping the growth of bacteria.

This antibiotic treats only bacterial infections. It will not work for viral infections (e.g., common cold, flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.

This medication is given by injection by a health care professional. Follow all instructions for preparation and use of this product. Before using this product, check it visually for particles or discoloration. If either is present, do not use the liquid. If you have questions about the use of this medication, consult the pharmacist.

The dosage is based on your medical condition and response to therapy. For children, the dosage is also based on weight.

Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, use this drug at evenly spaced intervals.

Continue to use this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Inform your doctor if your condition persists or worsens.

If this medication is injected into a muscle, pain at the injection site may occur. If this effect persists or worsens, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she 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 immediately if any of these unlikely but serious side effects occur: pain/swelling at injection site (if this drug is injected into a vein), joint/muscle pain, muscle weakness, swelling of ankles/feet.

Tell your doctor immediately if any of these rare but very serious side effects occur: dark/cloudy urine, extreme tiredness, fast/slow/irregular heartbeat, new signs of infection (e.g., fever, persistent sore throat), easy bruising/bleeding, change in the amount of urine, numbness/tingling of arms/legs, seizures, uncontrolled movements, confusion.

If used to treat syphilis or other spirochetal infections (e.g., Lyme disease), this medication may cause a condition known as Jarisch-Herxheimer reaction. This condition may occur 1 to 2 hours after you receive the medication and can last up to 24 hours. Notify your doctor immediately if you experience any of these symptoms: fever/chills, muscle pain, worsening of skin sores, fast heartbeat, fast breathing, dizziness, flushing.

This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur weeks to months after treatment has stopped. Tell your doctor immediately if you develop persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool. Do not use anti-diarrhea products or narcotic pain medications if you have any of these symptoms because these products may make them worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

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.

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.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using this medication, tell your doctor or pharmacist if you are allergic to it; or to penicillin or cephalosporin antibiotics; or to corn (for products containing dextrose); or if you have any other allergies.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: asthma, kidney disease.

Certain products of this medication contain sodium. Consult your doctor or pharmacist if you are on a salt-restricted diet or if you have a condition that could be worsened by an increase in salt intake (e.g., congestive heart failure).

Certain products of this medication contain potassium. Consult your doctor or pharmacist if you are taking potassium supplements, salt substitutes containing potassium, or medications that can increase potassium (e.g., ACE inhibitors such as lisinopril), or if you have a high potassium level (hyperkalemia).

Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, elderly people may be at greater risk for side effects while using this drug.

Kidney function is not fully developed in newborns and infants. This medication is removed by the kidneys. Therefore, newborns and infants may be at greater risk for side effects while using this drug.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breast-feeding.

Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: "blood thinners" (e.g., warfarin), live bacterial vaccines, methotrexate, NSAIDS (e.g., aspirin, indomethacin), probenecid, tetracyclines, "water pills"/diuretics (e.g., furosemide, thiazide diuretics such as hydrochlorothiazide).

Give aminoglycosides (e.g., gentamicin) separately from penicillin. Do not mix together in the same IV fluid.

Low-dose aspirin should be continued if prescribed by your doctor for specific medical reasons such as heart attack or stroke prevention (usually at dosages of 81-325 milligrams per day). Ask your doctor or pharmacist for more details.

This medication may decrease the effectiveness of combination-type hormonal birth control (e.g., pills, patch). This can result in pregnancy. Ask your doctor or pharmacist for details. Discuss whether you should use additional reliable birth control methods while you are using hormonal birth control along with penicillin.

This medication may interfere with certain laboratory tests (including certain urine glucose tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US National Poison Hotline at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: seizures, confusion, mental/mood changes (e.g., agitation).

This medication has been prescribed for your current condition only. Do not use it later for another infection unless told to do so by your doctor. A different medication may be necessary in that case.

Laboratory and/or medical tests (e.g., kidney function, complete blood count, potassium/sodium levels) may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

This medication must be stored properly. Review storage instructions with the pharmacist. Check the expiration date before using. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

Information last revised October 2008 Copyright(c) 2008 First DataBank, Inc.