How do you take Crystalline Penicillin?

This drug is given only as an injection into a vein (IV) or muscle (IM) by a doctor or nurse in a hospital or clinic. Adults usually receive 1 to 5 million units every 4 to 6 hours depending on how serious the infection is. Do not try to inject yourself at home; always let a trained health worker give it to you.

What are the side effects of Crystalline Penicillin?

Pain or swelling at the injection site, mild diarrhoea or stomach upset, mild skin rash or itching, nausea

Who should not take Crystalline Penicillin?

People who are allergic to penicillin or any penicillin-type antibiotics (like amoxicillin or ampicillin) should not take this drug. If you have ever had a serious allergic reaction to any antibiotic, tell your doctor before receiving this injection. People with severe kidney problems need a dose adjustment.

Prescription

Antibiotic (Penicillin)

Crystalline Penicillin

Q: What is Crystalline Penicillin used for?

Serious infections like pneumonia, meningitis (infection of the brain covering), blood infection (sepsis), throat infection, wound infection, heart valve infection, tetanus, and other severe bacterial infections

Last reviewed July 2026

Who is this for?

For adults (18+). Standard adult dosing applies: see the How to Take tab for full instructions.

What is this drug?

Crystalline Penicillin (also called Penicillin G or Benzylpenicillin) is an antibiotic injection that kills bacteria by breaking down their protective walls, stopping them from growing and spreading in your body.

How it works

Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins and preventing cross-linking of peptidoglycan, causing cell wall disruption and bactericidal killing of susceptible gram-positive and some gram-negative bacteria.

What is it used for?

Serious infections like pneumoniameningitis (infection of the brain covering)blood infection (sepsis)throat infectionwound infectionheart valve infectiontetanusand other severe bacterial infections

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Bacterial Infections Skin Infections Throat & Chest Infections Meningitis Sepsis & Severe Infections

Prescription Required

You need a doctor's prescription to buy this drug.

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What to watch out for

Always receive this injection in a proper hospital or clinic; never buy and inject at home or from unqualified people. Make sure you complete the full course of treatment even if you start feeling better, otherwise the infection can come back stronger. Tell your doctor immediately if you notice any rash, itching, or difficulty breathing after the injection, as penicillin allergy can be life-threatening.

Common Side Effects

Pain or swelling at the injection site
mild diarrhoea or stomach upset
mild skin rash or itching
nausea

Serious Side Effects

Severe allergic reaction (difficulty breathing, swelling of face or throat, widespread rash): this is a medical emergency. Severe watery or bloody diarrhoea that won't stop. Seizures or fits
especially at very high doses.

Drug Interactions

Probenecid (a gout medication) increases penicillin levels in the blood and may increase side effects. Blood thinners like warfarin may work differently when combined with Crystalline Penicillin, so your doctor should monitor you. Methotrexate (used for arthritis or cancer) can become more toxic when used together with this drug.

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Pregnancy & Breastfeeding Warning

Crystalline Penicillin is generally considered safe during pregnancy and breastfeeding, but always let your doctor know if you are pregnant or nursing before receiving it.

Who Should NOT Take This

People who are allergic to penicillin or any penicillin-type antibiotics (like amoxicillin or ampicillin) should not take this drug. If you have ever had a serious allergic reaction to any antibiotic
tell your doctor before receiving this injection. People with severe kidney problems need a dose adjustment.

How to Store

Store the unopened powder in a cool, dry place below 25°C, away from direct sunlight and heat, which is especially important in hot Nigerian weather. Once mixed with water, use it immediately or keep it in a refrigerator and use within 24 hours. Always keep out of reach of children.

For information only: not medical advice. Always talk to a doctor or pharmacist before changing your medication.