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Penicillin G benzathine

Generic Name: penicillin G benzathine (PEN i SILL in G BEN za theen)
Brand Name: Bicillin L-A

Medically reviewed by on Sep 12, 2019 – Written by Cerner Multum

What is penicillin G benzathine?

Penicillin G benzathine is a slow-onset antibiotic that is used to treat many types of mild to moderate infections caused by bacteria, including strep infections or syphilis. Penicillin G benzathine is also used to prevent the symptoms of rheumatic fever.

Penicillin G benzathine may also be used for purposes not listed in this medication guide.

Important Information

You should not be treated with penicillin G benzathine if you are allergic to penicillin.

Before taking this medicine

You should not be treated with this medicine if you are allergic to penicillin.

Tell your doctor if you have ever had:

  • an allergic reaction to a cephalosporin antibiotic (Keflex, Omnicef, and others);

  • any type of allergy;

  • asthma or breathing problems;

  • heart disease; or

  • kidney disease.

Tell your doctor if you are pregnant or breastfeeding.

How is penicillin G benzathine given?

Penicillin G benzathine is injected into a muscle. A healthcare provider can teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Penicillin G benzathine must be injected slowly and deeply into a muscle of the buttock or hip.

Do not inject penicillin G benzathine near or into an artery, vein, or nerve. Dangerous or fatal side effects could occur.

Prepare an injection only when you are ready to give it. Do not use if the medicine has changed colors or has particles in it. Call your pharmacist for new medicine.

Penicillin G benzathine is sometimes given as a single injection. In some cases you may need an injection once every 2 to 4 weeks, or once a week for only 3 weeks. How often you receive an injection will depend on the type of infection you have.

Be sure to receive all doses your doctor has prescribed, even if your symptoms quickly improve. Skipping doses can increase your risk of infection that is resistant to medication. Penicillin G benzathine will not treat a viral infection such as the flu or a common cold.

After you have finished all doses, your doctor may want to do tests to make sure your infection has completely cleared up.

Store in the refrigerator, do not freeze.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your penicillin G benzathine injection.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose may cause a seizure.

What should I avoid while receiving penicillin G benzathine?

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.

Penicillin G benzathine side effects

Get emergency medical help if you have signs of an allergic reaction: hives; fever, chills, joint pain; difficult breathing; swelling of your face, lips, tongue, or throat.

Some side effects may occur if the medicine has been accidentally injected near a vein or nerve. Tell your doctor right away if you have:

  • pain, numbness, tingling, burning, or feeling cold;

  • pale or mottled skin, blue-colored lips, fingers, or toes;

  • severe pain, tingling, weakness, or swelling in your lower leg;

  • weakness in your arms or legs; or

  • blistering, peeling, discoloration, or painful skin changes where the medicine was injected.

Also call your doctor at once if you have:

  • severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);

  • a light-headed feeling, like you might pass out;

  • slow heart rate, weak pulse, fainting, slow breathing (breathing may stop);

  • pounding heartbeats or fluttering in your chest;

  • confusion, agitation, hallucinations (seeing or hearing things that aren't real), extreme fear;

  • a seizure;

  • warmth, redness, or bleeding where the medicine was injected;

  • easy bruising or bleeding;

  • pale or yellowed skin, dark colored urine;

  • urination problems; or

  • signs of a new infection--fever, chills, mouth sores, warmth or redness under your skin, vaginal itching or discharge.

Common side effects may include:

  • nausea, vomiting, diarrhea;

  • itching, sweating, allergic reaction;

  • flushing (sudden warmth, redness, or tingly feeling);

  • feeling anxious, nervous, weak, or tired;

  • headache, dizziness, drowsiness;

  • muscle or joint pain; or

  • pain, swelling, bruising, or a hard lump where an injection was given.

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.

What other drugs will affect penicillin G benzathine?

Other drugs may affect penicillin G benzathine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

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.