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Penicillin G (benzylpenicillin procaine, antibiotic)

Penicillin G is an antibiotic under the class of penicillin. Unlike other many other antibiotics, penicillin G is only for intramuscular (IM) injection. Antibiotics can only be purchased with a physician’s prescription. Do not use antibiotics for treating allergies, viral infection, other other non-bacterial infection.

Other names for penicillin G include the following:

  • Procaine benzylpenicillin
  • Benzylpenicillin procaine
  • Pen G

Uses

What is penicillin G used for?

Penicillin G is used to treat many different types of infections caused by bacteria, including syphilis (a sexually transmitted disease).

How should I take penicillin G?

Read the directions on the packaging for complete information. Check the label and expiration date.

For parenteral dosage forms, only a licensed healthcare professional should administer it via IM injection.

How do I store penicillin G?

Dry powder

This drug is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store it in the bathroom or the freezer.

Solution

This drug is best stored in the refrigerator (between 2-8°C). To prevent drug damage, you should not store it in the bathroom or the freezer.

There may be different brands of this drug that may have different storage needs. So, it is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush this product down the toilet or pour them into a drain unless instructed to do so. Additionally, it is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & Warnings

What should I know before using penicillin G?

Before using this drug, tell your doctor if you are/have:

  • Pregnant or breastfeeding.
  • Taking any other medicines. This includes any prescription, OTC, and herbal remedies.
    • Oral contraceptives
    • Using spermicides
  • An allergy to any of the ingredients of this product.
  • Any other illnesses, disorders, or medical conditions.

Is it safe during pregnancy or breastfeeding?

Unfortunately, there isn’t enough information about the safety of using this drug during pregnancy and breastfeeding. However, it is likely safe to take. Please always consult with your doctor to weigh the potential benefits and risks before taking any medication.

This medication is pregnancy risk category B according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A= No risk
  • B= No risk in some studies
  • C= There may be some risk
  • D= Positive evidence of risk
  • X= Contraindicated
  • N= Unknown

Side Effects

What side effects can occur from penicillin G?

Like all drugs, this product may have side effects. If they occur, side effects are generally mild and resolve once treatment is finished or the dose is lowered. Some reported side effects include:

  • Injection site pain or swelling
  • Vaginal itching or discharge
  • White patches in your mouth or throat (thrush)
  • Nausea, vomiting
  • Blurred vision, ringing in your ears
  • Headache, dizziness
  • Mild skin rash
  • Diarrhea

Seek medical attention immediately if you experience any of the following:

  • Hives or rashes
  • Difficulty breathing
  • Swelling of your face, lips, tongue, or throat
  • Peeling skin, severe pain, or changes in skin color
  • Dizziness, joint or muscle pain
  • Fast or pounding heartbeat
  • Numbness, tingling, pain, swelling, or redness in your arms or legs
  • Confusion, agitation, depression, unusual thoughts or behavior
  • Chest pain, problems with vision or speech
  • Fever, chills, dizziness, muscle pain, rapid breathing or heart rate
  • Uncontrolled muscle movements, problems with balance or walking
  • Pale skin, easy bruising or bleeding, unusual weakness
  • Sore throat, flu symptoms
  • Urinating less than usual or not at all
  • Rash or itching with swollen glands, joint pain, or general ill feeling
  • Slow heart rate, weak pulse, fainting, slow breathing

However, not everyone experiences these side effects. In addition, some people may experience other side effects. So, if you have any concerns about a side effect, please consult your doctor or pharmacist.

Interactions

What drugs may interact with penicillin G?

This medication may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects.

To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist.

Drugs with known interactions:

  • Probenecid
  • A blood thinner (e.g. warfarin)
  • A diuretic or “water pill” (e.g. hydrochlorothiazide)
  • Methotrexate
  • Tetracycline antibiotics (e.g. minocycline, doxycycline)
  • NSAIDs
  • Cephalosporins (all generations)

If you experience an adverse drug interaction, inform your doctor immediately to reevaluate your treatment plan. Approaches include dose adjustment, drug substitution, or ending therapy.

Does food or alcohol interact with penicillin G?

This drug may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with penicillin G?

This drug may interact with underlying conditions. This interaction may worsen your health condition or alter the way the drug works. Therefore, it is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

  • Asthma
  • Known allergy to penicillin
  • Kidney impairment

Dosage

The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication.

What is the dose for an adult?

Syphilis

  • Early stage: Administer 600 mg once a day via deep IM injection for 10 days.
  • Late stage: Administer 600 mg once a day via deep IM injection for 17 days.
  • Neurosyphilis: Administer 1.8 to 2.4 g once a day via deep IM injection for 17 days, with probenecid.

Anthrax

  • Inhalational anthrax treatment and prophylaxis: Administer 1.2 g via deep IM injection every 12 hours for 60 days.
  • Cutaneous infection: Administer 0.6 to 1 g once a day via deep IM injection.

Fusospirochetosis, Invasive Group A beta-hemolytic streptococcal disease, Pneumococcal pneumonia, Staphylococcal infections

Administer 1.5 g once a day via deep IM injection for 2 to 5 days. Adjust the 4th and 5th dose depending on the severity of the infection.

Diphtheria

Administer 300 to 600 mg once a day via deep IM injection with antitoxin. For carriers, administer 300 mg once a day for 10 days.

Uncomplicated gonorrhea

Administer 1 g once a day via deep IM injection for 7 to 14 days – OR – up to 4.8 g as a single dose together with probenecid.

What is the dose for a child?

Congenital syphilis

Administer 50 mg per kg of body weight once a day via deep IM injection for 10 days.

Anthrax

Inhalational anthrax treatment and prophylaxis: Administer 25 mg per kg of body weight every 12 hours for 60 days via deep IM injection, up to 1.2 g per dose.

Pneumococcal pneumonia

Administer 50 mg per kg of body weight once a day via deep IM injection for 10 days.

Diphtheria

For carriers, administer 300 mg as a single dose via deep IM injection for 10 days.

How is penicillin G available?

Penicillin G is available in the following dosage forms and strengths:

  • Suspension for injection 600,000 units/1 mL, 1,200,00 units/2 mL

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to the nearest emergency room.

What should I do if I miss a dose?

If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose. Avoid missing doses to prevent antibiotic resistance and treatment failure.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Sources

Procaine Benzylpenicillin https://www.mims.com/philippines/drug/info/procaine%20benzylpenicillin?mtype=generic Accessed July 25, 2021

Procaine Penicillin https://www.ncbi.nlm.nih.gov/books/NBK482355/ Accessed July 25, 2021

Questions and Answers for Consumers on Penicillin G Procaine https://www.fda.gov/drugs/bioterrorism-and-drug-preparedness/questions-and-answers-consumers-penicillin-g-procaine Accessed July 25, 2021

PENICILLIN G PROCAINE https://www.pfizermedicalinformation.com/en-us/penicillin-g-procaine Accessed July 25, 2021

Benzylpenicillin [Penicillin G] Procaine. Lexi-Drugs. Lexicomp. Wolters Kluwer Health, Inc. Riverwoods, IL. Accessed July 25, 2021. http://online.lexi.com

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Written by Stephanie Nicole Nera, RPh, PharmD Updated just now
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