Penicillin G benzathine

Name: Penicillin G benzathine

Penicillin G benzathine Interactions

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 penicillin G benzathine and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Tell your doctor about all medicines you use, and those you start or stop using during your treatment with penicillin G benzathine, especially:

  • methotrexate;
  • probenecid;
  • birth control pills;
  • a blood thinner such as warfarin (Coumadin, Jantoven); or
  • a blood thinner such as warfarin, Coumadin; or
  • a tetracycline antibiotic--doxycycline, minocycline, tetracycline.

This list is not complete. Other drugs may interact with penicillin G benzathine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Penicillin G Benzathine Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • allopurinol (Aloprim, Zyloprim)
  • probenecid (Probalan, Benemid)
  • methotrexate (Rheumatrex, Trexall)
  • birth control pills

This is not a complete list of penicillin G benzathine drug interactions. Ask your doctor or pharmacist for more information.

Penicillin G Benzathine Precautions

Serious side effects have been reported with penicillin G benzathine including:

  • hypersensitivity (severe allergic reaction). This type of reaction may be serious and possibly fatal. These reactions are more likely to occur in those with a history of penicillin hypersensitivity and/or a history of sensitivity to multiple allergens. Tell your healthcare provider right away if you start to develop signs or symptoms of a hypersensitivity reaction, which include the following:
    • chest pain
    • swelling of the face, eyes, lips, tongue, arms, or legs
    • difficulty breathing or swallowing
    • fainting
    • rash
  • diarrhea. Diarrhea is a common problem caused by antibiotics, and it usually ends when the antibacterial is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as 2 or more months after having taken their last dose of the antibacterial. If diarrhea is severe or lasts more than 2 or 3 days, contact your doctor, as this may be a sign of an infection of the bowels.
  • superinfection. Penicillin G benzathine should not be used for extended periods. Prolonged use can lead to the growth of dangerous organisms that are resistant or unaffected by penicillin G benzathine. Take this medication for the duration prescribed by your doctor.

Do not take penicillin G benzathine if you:

  • are allergic to penicillin G benzathine or any of its ingredients

Other Requirements

  • Store in a refrigerator at 2° to 8°C (36° to 46°F).
  • Keep from freezing.
  • Keep this and all medicines out of the reach of children.

Uses of Penicillin G Benzathine

  • It is used to treat bacterial infections.

What do I need to tell my doctor BEFORE I take Penicillin G Benzathine?

  • If you have an allergy to penicillin, benzathine, or any other part of this medicine.
  • If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If you are taking tetracycline.

This is not a list of all drugs or health problems that interact with penicillin G benzathine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this medicine with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

Consumer Information Use and Disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this medicine, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take penicillin G benzathine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to penicillin G benzathine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Review Date: October 4, 2017


Store at 2°C to 8°C (36°F to 46°F); do not freeze. The following stability information has also been reported: May be stored at 25°C (77°F) for 7 days (Cohen, 2007).

ALERT U.S. Boxed Warning

Appropriate administration:

Not for intravenous (IV) use. Do not inject IV or admix with other IV solutions. There have been reports of inadvertent IV administration of penicillin G benzathine that has been associated with cardiorespiratory arrest and death. Prior to administration of this drug, carefully read the Administration and Dosage section.


Concerns related to adverse effects:

• Hypersensitivity reactions: Serious and occasionally severe or fatal hypersensitivity (anaphylactic) reactions have been reported in patients on penicillin therapy, especially with a history of beta-lactam hypersensitivity (including cephalosporins), history of sensitivity to multiple allergens, or previous IgE-mediated reactions (eg, anaphylaxis, angioedema, urticaria). Serious anaphylactic reactions require immediate emergency treatment with epinephrine, oxygen, intravenous steroids and airway management (including intubation) as indicated.

• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.

Disease-related concerns:

• Renal impairment: Use with caution in patients with renal impairment.

• Seizure disorders: Use with caution in patients with a history of seizure disorder; high levels, particularly in the presence of renal impairment, may increase risk of seizures.

• Syphilis/neurosyphilis use: CDC and AAP do not currently recommend the use of penicillin G benzathine for the initial treatment regimen for congenital syphilis or neurosyphilis due to reported treatment failures and lack of published clinical data on its efficacy (CDC [Workowski 2015]).

Other warnings/precautions:

• Appropriate administration: [US Boxed Warning]: Not for intravenous use; cardiopulmonary arrest and death have occurred from inadvertent IV administration. Administer by deep IM injection only. Quadriceps femoris fibrosis and atrophy have been reported after repeated IM injections of penicillin preparations into the anterolateral thigh. Injection into or near an artery or nerve could result in severe neurovascular damage or permanent neurological damage.

• Appropriate use: Use only for treatment of infections due to penicillin G sensitive gram positive organisms, few gram-negative organisms such as Neisseria gonorrhoeae, and some anaerobes and spirochetes. Use only for infections susceptible to the low and very prolonged serum concentrations of benzathine penicillin G.

• Prolonged use: Extended duration of therapy or use associated with high serum concentrations (eg, in renal insufficiency) may be associated with an increased risk for some adverse reactions (neutropenia, hemolytic anemia, serum sickness).

Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies. Penicillin G benzathine crosses the placenta (Nathan 1993; Weeks 1997). Maternal use of penicillins has generally not resulted in an increased risk of adverse fetal effects. Penicillin G is the drug of choice for treatment of syphilis during pregnancy (CDC [Workowski 2015]).

Usual Adult Dose for Pinta

1.2 million units IM as a single dose

Usual Pediatric Dose for Syphilis - Early

US CDC Recommendations:
1 month or older:
-Primary, secondary, and early latent syphilis: 50,000 units/kg IM as a single dose
Maximum dose: 2.4 million units/dose

-Late latent syphilis: 50,000 units/kg IM once a week for 3 weeks (total dose: 150,000 units/kg)
Maximum dose: 2.4 million units/dose (maximum total dose: 7.2 million units)

Comments: Current guidelines should be consulted for additional information.


-ADMINISTRATION: This drug is not for IV use; it must not be injected IV or admixed with other IV solutions. Inadvertent IV administration of this drug has been associated with cardiorespiratory arrest and death. The manufacturer product information should be consulted before administering this drug.

Consult WARNINGS section for additional precautions.