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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 on January 22, 2018

What is penicillin G benzathine?

Penicillin G benzathine is a slow-onset antibiotic that fights bacteria in your body.

Penicillin G benzathine is used to treat many different types of severe infections, including strep infections, rheumatic fever, and syphilis.

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

Important Information

You should not receive this medication 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.

Before you receive penicillin G benzathine, tell your doctor if you have asthma or a history of allergies, liver disease, kidney disease, or heart disease.

Be sure to receive all doses your doctor has prescribed. Your symptoms may get better before the infection is completely cleared.

After you have finished your treatment with penicillin G benzathine, your doctor may want to do tests to make sure your infection has completely cleared up.

Before taking this medicine

You should not receive this medication if you are allergic to penicillin. Tell your doctor if you have ever had an allergic reaction to a cephalosporin antibiotic such as cefdinir (Omnicef), cefprozil (Cefzil), cefuroxime (Ceftin), cephalexin (Keflex), and others.

To make sure penicillin G benzathine is safe for you, tell your doctor if you have:

  • asthma or a history of allergies;

  • liver disease;

  • kidney disease; or

  • heart disease.

FDA pregnancy category B. This medication 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 benzathine can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

How is penicillin G benzathine given?

Penicillin G benzathine is injected into a muscle. A healthcare provider will give you this injection.

Penicillin G benzathine must be injected slowly into a muscle of the buttock.

Penicillin G benzathine is sometimes given only once or only for a few days until your symptoms clear up. Be sure to receive all doses your doctor has prescribed. Your symptoms may get better before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics.

After you have finished your treatment with penicillin G benzathine, your doctor may want to do tests to make sure your infection has completely cleared up.

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.

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

Penicillin G benzathine side effects

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

Call your doctor at once if you have:

  • diarrhea that is watery or bloody;

  • fever, swollen glands, rash or itching, muscle or joint pain, night sweats, general ill feeling;

  • a feeling like you might pass out;

  • skin rash with bruising, severe tingling, numbness, pain, muscle weakness;

  • pale or yellowed skin, dark colored urine, weakness;

  • easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;

  • little or no urinating;

  • fast or pounding heartbeats;

  • slow heart rate, weak pulse, fainting, slow breathing;

  • confusion, agitation, hallucinations, ringing in your ears, unusual thoughts or behavior;

  • seizure (convulsions);

  • pain, swelling, bruising, irritation, or skin changes where the injection was given; or

  • hardening of your skin in the thigh where the injection was given, trouble bending your knee.

Common side effects may include:

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.

See also: Side effects (in more detail)

What other drugs will affect penicillin G benzathine?

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

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.

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.

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