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Pfizerpen is a fast-acting antibiotic that fights bacteria in your body.
Pfizerpen is used to treat many different types of severe infections, including strep and staph infections, diphtheria, meningitis, gonorrhea, and syphilis.
Pfizerpen is also used to prevent infections of the heart valves in people with certain heart conditions who need to have dental work or surgery.
Pfizerpen may also be used for purposes not listed in this medication guide.
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 Pfizerpen if you are allergic to penicillin. Tell your doctor if you have ever had an allergic reaction to a cephalosporin antibiotic such as Ceftin, Cefzil, Omnicef, Keflex, and others.
To make sure Pfizerpen is safe for you, tell your doctor if you have:
asthma or a history of allergies;
liver disease;
kidney disease;
heart disease;
if you take a diuretic or "water pill"; or
if you take any other antibiotics, including sulfa drugs.
Pfizerpen is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.
Penicillin G potassium can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
Pfizerpen is injected into a muscle or into a vein through an IV. You may be shown how to use an injection at home. Do not self-inject this medicine if you do not fully understand how to give the injection and properly dispose of used needles, IV tubing, and other items used to inject the medicine.
Pfizerpen may also be injected into the membrane surrounding the lungs, or into the fluid surrounding the spinal cord. A healthcare provider will give you this type of injection.
Pfizerpen is a powder medicine that must be mixed with a liquid (solvent) before using it. If you are using the injections at home, be sure you understand how to properly mix and store the medicine.
Store the powder at room temperature away from moisture and heat.
After mixing the powder with a liquid, store in the refrigerator and use it within 7 days. Do not freeze.
Pfizerpen that is supplied as a frozen solution should be stored in a deep freezer at a temperature of 4 degrees below 0 (F).
Thaw the solution either in a refrigerator or at room temperature. Do not heat the medicine to thaw it more quickly. Once the solution has been thawed, it should look clear.
Pfizerpen that is thawed in the refrigerator should be used within 14 days. If you have thawed the medicine at room temperature, you must use it within 24 hours. Do not refreeze.
Do not use Pfizerpen if it has changed colors or has particles in it. Call your pharmacist for new medication.
Use a disposable needle and syringe only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof "sharps" disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.
This medicine can cause false results with certain lab tests for glucose (sugar) in the urine. Tell any doctor who treats you that you are using Pfizerpen.
If you use this medicine long-term, your blood may need to be tested to make sure the medicine is not causing harmful effects. Your kidney or liver function may also need to be tested.
Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Pfizerpen will not treat a viral infection such as the flu or a common cold.
After you have finished your treatment with Pfizerpen, your doctor may want to do tests to make sure your infection has completely cleared up.
Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.
Seek emergency medical attention if you think you have used too much of Pfizerpen.
Overdose symptoms may include confusion, agitation, hallucinations, or seizure (convulsions).
Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, stop taking this medication and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
the first sign of any skin rash, no matter how mild;
red or scaly skin;
fever, chills, swollen glands, muscle or joint pain, fast heartbeats, general ill feeling;
a light-headed feeling, like you might pass out;
severe stomach pain, diarrhea that is watery or bloody;
little or no urinating;
bruising, severe tingling, numbness, pain, muscle weakness;
seizure (convulsions); or
unusual changes in mood or behavior.
Common side effects may include:
mild diarrhea;
headache;
black or hairy tongue; or
pain, swelling, bruising, or irritation around the IV needle.
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 penicillin G potassium, 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.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Medically reviewed by USARx EDITORIAL TEAM Last updated on 1/1/2020.
Source: Drugs.com Pfizerpen (www.drugs.com/mtm/pfizerpen.html).
Note: This document contains side effect information about penicillin g potassium. Some of the dosage forms listed on this page may not apply to the brand name Pfizerpen.
Applies to penicillin g potassium: injection solution reconstituted
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
For all uses of this drug:
Injection (if given in the muscle):
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.
Applies to penicillin g potassium: injectable powder for injection, intravenous solution
Allergic reactions have been reported with all penicillins and the incidence ranged from 0.7% to 10% in studies.
Hypersensitivity reactions with penicillin are more common and more serious with intravenous therapy, but have also been reported with oral therapy. An initial sensitizing exposure is required to stimulate the production of antigen-specific IgE before clinical manifestations of hypersensitivity are seen on the second exposure. There are numerous "hidden" environmental or occupational exposures to penicillin including in utero exposure, breast milk exposure, and occupational exposure.
Immediate anaphylactic reactions were very rare and generally occurred after parenteral therapy; however, a few cases of anaphylaxis have been reported after oral therapy.
Delayed reactions to penicillin have been reported within 1 to 2 weeks after therapy was started.
The Jarisch-Herxheimer reaction has started 1 to 2 hours after initiation of therapy and has stopped within 12 to 24 hours. The Herxheimer reaction may be due to the release of heat-stable pyrogen from spirochetes.
Hypersensitivity side effects have included immediate and delayed allergic reactions. Immediate reactions generally occurred within 20 minutes of use and the severity ranged from urticaria and pruritus to angioneurotic edema, laryngospasm, bronchospasm, hypotension, vascular collapse, and death. A different type of immediate reaction, an accelerated reaction, occurred 20 minutes to 48 hours after use and included urticaria, pruritus, fever, and, occasionally, laryngeal edema. Manifestations of delayed reactions to penicillin included serum sickness-like symptoms, i.e., fever, malaise, urticaria, myalgia, arthralgia, abdominal pain, and various skin rashes (ranging from maculopapular eruptions to exfoliative dermatitis). Hypersensitivity myocarditis, eosinophilia, allergic vasculitis, asthenia, pain, reactions resembling serum sickness (including chills, fever, edema, arthralgia, and prostration), and anaphylaxis (severe and occasionally fatal) have been reported. The Jarisch-Herxheimer reaction (characterized by fever, chills, myalgias, headache, exacerbation of cutaneous lesions, tachycardia, hyperventilation, vasodilation with flushing, and mild hypertension) has been reported during penicillin treatment of patients with syphilis or other spirochaetal infections.
Cardiovascular side effects have included cardiac arrhythmias and cardiac arrest.
Gastrointestinal side effects have included Clostridium difficile associated diarrhea and pseudomembranous colitis; onset has occurred during or after therapy. Nausea, vomiting, diarrhea, stomatitis, black or hairy tongue, and other symptoms of gastrointestinal irritation have been reported, especially during oral therapy.
Metabolic side effects have included serious and even fatal electrolyte disturbances (i.e., hyperkalemia) with large intravenous doses since 1 million units of penicillin G potassium contains 1.68 mEq of potassium ion. Severe or fatal potassium poisoning (signs included hyperreflexia, convulsions, and coma) has been reported in patients receiving continuous intravenous therapy in high doses (10 million to 100 million units/day), especially in the presence of renal insufficiency.
Severe neurologic reactions were most often seen with penicillin doses of 18 million to 80 million units daily. These reactions frequently abated after discontinuation of penicillin. In several cases, penicillin was restarted at a lower dose with no further sequelae. In one review, the authors found that cerebral spinal fluid (CSF) penicillin levels were higher in patients with seizures than in those without. CSF penicillin levels ranged from 12 to 61 units/mL in the seizure group with the highest CSF concentrations, compared to 7.8 units/mL in the group without seizures.
Nervous system side effects have rarely included neuropathy, which was usually associated with high intravenous dosage. Neurotoxic reactions (including hyperreflexia, myoclonic twitches, seizures, and coma) have been reported after massive intravenous doses were administered, and were more likely in patients with renal dysfunction. Severe reactions (including myoclonus, seizures, auditory and visual hallucinations, and decreased mentation) have been reported with high dose penicillin therapy or in patients with renal dysfunction. Neurologic reactions occurred frequently in patients with renal dysfunction. Neurovascular damage, headache, tremor, confusion, agitation, aseptic meningitis, and coma have been reported.
Renal tubular damage and interstitial nephritis resolved in most patients after penicillin G was discontinued.
Nephropathy has been reported rarely and was usually associated with high intravenous dosage.
Renal side effects associated with large intravenous doses of penicillin G have included renal tubular damage and interstitial nephritis. Symptoms of this reaction included fever, rash, eosinophilia, proteinuria, eosinophiluria, hematuria, and a rise in serum urea nitrogen. Increased BUN and creatinine, renal failure, and nephropathy have been reported.
Hematologic side effects have included hemolytic anemia, anemia, leukopenia, neutropenia, thrombocytopenia, Coombs-positive hemolytic anemia, and a bleeding diathesis secondary to platelet dysfunction.
Hemolytic anemia, leukopenia, and thrombocytopenia have been reported rarely and were usually associated with high intravenous dosage.
Neutropenia resolved after penicillin was discontinued.
Coombs-positive hemolytic anemia (an uncommon reaction) was reported in patients treated with greater than 10 million units/day of intravenous penicillin G and who previously received large doses of the drug.
A bleeding diathesis secondary to platelet dysfunction has been associated with large doses of penicillin.
Local side effects have included injection site pain with intravenous administration, phlebitis, thrombophlebitis, and neurovascular damage.
Genitourinary side effects have included hematuria, proteinuria, and eosinophiluria.
Dermatologic side effects have included rash and urticaria. Contact dermatitis has been reported in those who prepared penicillin solutions.
A 28-year-old female developed jaundice, fever, epidermolysis, abnormal liver function tests, and cholestasis several days after receiving a single dose of penicillin intramuscularly. Her liver dysfunction continued for up to 18 months. She had taken acetaminophen concurrently but denied alcohol use.
Hepatic side effects have included increased SGOT, reversible hepatotoxicity, jaundice, and prolonged cholestasis.
Medically reviewed by USARx EDITORIAL TEAM Last updated on 1/1/2020.
Source: Drugs.com Pfizerpen (www.drugs.com/mtm/pfizerpen.html).
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