Penicillin G Potassium (pen-i-SIL-in G poe-TAS-ee-um)
There may be other brand names for this medicine.
Pfizerpen, Amerinet Choice Pfizerpen, Novaplus Pfizerpen
When This Medicine Should Not Be Used
You should not use this medicine if you have had an allergic reaction to any type of penicillin.
How to Use This Medicine
- Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot into a muscle or a vein, or directly into the infected area of your body.
- A nurse or other trained health professional will give you this medicine. It may also be given by a home health caregiver.
- You may be taught how to give your medicine at home. Make sure you understand all instructions before giving yourself an injection. Do not use more medicine or use it more often than your doctor tells you to.
- You will be shown the body areas where this shot can be given. Use a different body area each time you give yourself a shot. Keep track of where you give each shot to make sure you rotate body areas.
- Use a new needle and syringe each time you inject your medicine.
- Keep using this medicine for the full treatment time, even if you feel better after the first few doses. Your infection may not clear up if you stop using the medicine too soon.
If a dose is missed:
- If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.
- If you miss more than one dose, call your doctor for instructions.
How to Store and Dispose of This Medicine
- Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
- If you store this medicine at home, keep it in the refrigerator. Do not freeze. You may take the medicine out of the refrigerator 1 hour before using it to allow it to warm to room temperature.
- Throw away used needles in a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.
- Keep all medicine out of the reach of children and never share your medicine with anyone.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
- Make sure your doctor knows if you are also using probenecid (Benemid®), tetracycline, or erythromycin (Erythro-Tab®, E-Mycin®).
- Birth control pills, implants, or shots may not work while you are using penicillin. To keep from getting pregnant, use another form of birth control such as condoms, a diaphragm, or contraceptive foam or jelly.
Warnings While Using This Medicine
- Make sure your doctor knows if you are pregnant or breastfeeding, or if you have asthma or have ever had an allergic reaction to a cephalosporin antibiotic (such as cefaclor, cefadroxil, cephalexin, Ceftin®, Keflex®).
- If you have severe diarrhea, ask your doctor before taking any medicine to stop the diarrhea.
Possible Side Effects While Using This Medicine
Call your doctor right away if you notice any of these side effects:
- Allergic reaction: Itching or hives, swelling in face or hands, swelling or tingling in the mouth or throat, tightness in chest, trouble breathing
- Diarrhea (may be watery or contain blood)
- Fast, slow, or irregular heartbeat
If you notice these less serious side effects, talk with your doctor:
- Nausea or vomiting
- Pain or irritation where your shot is given
- Vaginal itching or discharge
If you notice other side effects that you think are caused by this medicine, tell your doctor
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
Review Date: 2011-02-04