Brand Name(s):

• Pfizerpen®¶

WHY is this medicine prescribed?

Your doctor has ordered penicillin, an antibiotic, to help treat your infection. The drug will be either injected into a large muscle (such as your buttock or hip) or added to an intravenous fluid that will drip through a needle or catheter placed in your vein for 30 minutes or more, four to six times a day.

Penicillin eliminates bacteria that cause many kinds of infections, including pneumonia; meningitis; and skin, bone, joint, stomach, blood, and heart valve infections. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Your health care provider (doctor, nurse, or pharmacist) may measure the effectiveness and side effects of your treatment using laboratory tests and physical examinations. It is important to keep all appointments with your doctor and the laboratory. The length of treatment depends on how your infection and symptoms respond to the medication.

What SPECIAL PRECAUTIONS should I follow?

Before administering penicillin,

• tell your doctor and pharmacist if you are allergic to penicillin, cephalosporins [e.g., cefaclor (Ceclor), cefadroxil (Duricef), or cephalexin (Keflex)], or any other drugs.
• tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially other antibiotics, anticoagulants ('blood thinners') such as warfarin (Coumadin), aspirin or other nonsteroidal anti-inflammatory medications such as naproxen (Anaprox) or ibuprofen (Motrin), atenolol (Tenormin), diuretics ('water pills'), oral contraceptives, probenecid (Benemid), and vitamins.
• tell your doctor if you have or have ever had kidney or liver disease, allergies, asthma, blood disease, colitis, stomach problems, or hay fever.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking penicillin, call your doctor.
• if you have diabetes and regularly check your urine for sugar, use Clinistix or TesTape. Do not use Clinitest tablets because penicillin may cause false positive results.

HOW should this medicine be used?

Before you administer penicillin, look at the solution closely. It should be clear and free of floating material. Gently squeeze the bag or observe the solution container to make sure there are no leaks. Do not use the solution if it is discolored, if it contains particles, or if the bag or container leaks. Use a new solution, but show the damaged one to your health care provider.

It is important that you use your medication exactly as directed. Do not stop your therapy on your own for any reason because your infection could worsen and result in hospitalization. Do not change your dosing schedule without talking to your health care provider. Your health care provider may tell you to stop your infusion if you have a mechanical problem (such as a blockage in the tubing, needle, or catheter); if you have to stop an infusion, call your health care provider immediately so your therapy can continue.

What SIDE EFFECTS can this medicine cause?

What should I know about STORAGE and DISPOSAL of this medication?

• Your health care provider probably will give you a several-day supply of penicillin at a time. If you are receiving penicillin intravenously (in your vein), you probably will be told to store it in the refrigerator or freezer.
• Take your next dose from the refrigerator 1 hour before using it; place it in a clean, dry area to allow it to warm to room temperature.
• If you are told to store additional penicillin in the freezer, always move a 24-hour supply to the refrigerator for the next day's use.
• Do not refreeze medications.

If you are receiving penicillin intramuscularly (in your muscle), your health care provider will tell you how to store it properly.

Store your medication only as directed. Make sure you understand what you need to store your medication properly.

Keep your supplies in a clean, dry place when you are not using them, and keep all medications and supplies out of reach of children. Your health care provider will tell you how to throw away used needles, syringes, tubing, and containers to avoid accidental injury.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Last Reviewed: September 1, 2010.