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URL of this page: https://medlineplus.gov/druginfo/meds/a615051.html

Penicillin G Benzathine Injection

pronounced as (pen" i sil' in g ben' za theen)

IMPORTANT WARNING:

Penicillin G benzathine injection should never be given intravenously (into a vein) because this may cause serious or life-threatening side effects or death.

Why is this medication prescribed?

Penicillin G benzathine injection is used to treat and prevent certain infections caused by bacteria. Penicillin G benzathine injection is in a class of antibiotics called penicillins. It works by killing bacteria that cause infections.

Antibiotics such as penicillin G benzathine injection will not work for colds, flu, or other viral infections. Taking antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

How should this medicine be used?

Penicillin G benzathine injection comes as a suspension (liquid) in a prefilled syringe to be given intramuscularly (into a muscle) by a doctor or nurse in a medical facility. Penicillin G benzathine injection is usually given a single dose but may be repeated in 7 days for certain infections. Ask your doctor if you have any questions about how many doses you will need or when you will receive them.

You should begin to feel better during the first few days of treatment with penicillin G benzathine injection. If your symptoms do not improve or get worse, call your doctor.

If your doctor has told you that you will need additional doses of penicillin G benzathine injection, make sure to keep all appointments to receive your doses on schedule even if you are feeling better. If you stop using penicillin G benzathine injection too soon or skip doses, your infection may not be completely treated and the bacteria may become resistant to antibiotics.

Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before receiving penicillin G benzathine injection,

  • tell your doctor or pharmacist if you are allergic to this medication, any part of this medication, or any other medications, foods or substances. Tell your doctor or pharmacist about the allergy and what symptoms you had.
  • some medications should not be taken with penicillin G benzathine injection. Other medications may cause dosing changes or extra monitoring when taken with penicillin G benzathine injection. Make sure you have discussed any medications you are currently taking or plan to take before starting penicillin G benzathine injection with your doctor and pharmacist. Before starting, stopping, or changing any medications while taking penicillin G benzathine injection, please get the advice of your doctor or pharmacist.
  • tell your doctor if you have or have ever had asthma, allergies, hay fever, hives, or kidney disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while receiving penicillin G benzathine injection, call your doctor.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do if I forget a dose?

If you miss an appointment to receive penicillin G benzathine injection, call your doctor as soon as possible.

What side effects can this medication cause?

Penicillin G benzathine injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • nausea, vomiting
  • pain, swelling, lump, bleeding, or bruising in the area where the medication was injected

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

  • rash, hives, itching
  • difficulty breathing or swallowing; swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs; hoarseness
  • sore throat, chills, fever
  • headache
  • muscle or joint pain
  • weakness
  • fast heartbeat
  • severe diarrhea (watery or bloody stools) with or without fever and stomach cramps that may occur up to 2 months or more after your treatment
  • sudden onset of lower back pain, muscle weakness, numbness, and tingling
  • blue or black skin discoloration in the area where the medication was injected
  • skin blistering, peeling, or shedding in the area where the medication was injected
  • numbness of the arm or leg in which the medication was injected

Penicillin G benzathine injection may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

In case of emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

  • twitching
  • seizures

What other information should I know?

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to penicillin G benzathine injection.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

Brand names

  • Bicillin L-A®

Other names

  • Benzathine Benzylpenicillin
  • Benzathine Penicillin G
  • Benzylpenicillin Benzathine
  • Dibenzylethylenediamine Benzylpenicillin
Last Revised - 04/15/2026