How do you take Procaine Penicillin; Benzyl Penicillin Sodium?

This drug is given as an injection into the muscle (usually the buttocks) by a healthcare professional, so do not try to inject yourself at home. For adults, the usual dose is 1 to 2 mega units (MU) given once or twice daily, depending on the severity of your infection. Your doctor will decide the exact dose and how long you need it.

What are the side effects of Procaine Penicillin; Benzyl Penicillin Sodium?

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

Who should not take Procaine Penicillin; Benzyl Penicillin Sodium?

People who are allergic to penicillin or any type of penicillin-based antibiotic (if you have ever had a rash, swelling, or difficulty breathing after taking penicillin, tell your doctor immediately). People with a known allergy to procaine (a local anaesthetic). Those with a history of severe allergic reactions to cephalosporin antibiotics should use with caution.

Prescription

Antibiotic (Penicillin)

Procaine Penicillin; Benzyl Penicillin Sodium

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?

This is a combination antibiotic injection that contains two forms of penicillin: Procaine Penicillin (which releases slowly and works over a longer period) and Benzyl Penicillin Sodium (which works fast). Together, they kill bacteria causing infections by breaking down their protective walls.

How it works

Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins and preventing cross-linking of peptidoglycan strands, leading to cell wall degradation and bactericidal activity against susceptible gram-positive and gram-negative organisms.

What is it used for?

Serious bacterial infections, pneumonia, sore throat infections, skin infections, wound infections, sexually transmitted infections like syphilis and gonorrhoea, ear infections, tonsillitis

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Bacterial Infections Skin Infections Ear Infections Throat & Chest Infections STIs & Sexual Health

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What to watch out for

Always get this injection at a proper hospital, clinic, or pharmacy, never from roadside medicine sellers or unqualified persons, as incorrect injection technique can cause serious complications. Complete the full course of injections your doctor prescribed, even if you feel better, as stopping early can make the infection come back stronger. Do not share your prescription or leftover medication with anyone else, even if they have similar symptoms.

Common Side Effects

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

Serious Side Effects

Severe allergic reaction (difficulty breathing, swelling of face, lips, or throat, widespread rash): this is an emergency
go to hospital immediately. Seizures or convulsions
especially if too much is given. Severe watery or bloody diarrhoea that won't stop.

Drug Interactions

Methotrexate (used for arthritis or cancer): penicillin can increase its toxic effects. Probenecid (used for gout): increases penicillin levels in the blood, which your doctor may use intentionally. Blood-thinning drugs like warfarin: penicillin may increase bleeding risk, so inform your doctor if you take blood thinners.

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Pregnancy & Breastfeeding Warning

Penicillin is generally considered safe during pregnancy and breastfeeding, but always inform your doctor that you are pregnant or breastfeeding before receiving this injection.

Who Should NOT Take This

People who are allergic to penicillin or any type of penicillin-based antibiotic (if you have ever had a rash, swelling, or difficulty breathing after taking penicillin, tell your doctor immediately). People with a known allergy to procaine (a local anaesthetic). Those with a history of severe allergic reactions to cephalosporin antibiotics should use with caution.

How to Store

Store the powder in a cool, dry place below 25°C, avoiding direct sunlight and damp areas, which is important in Nigeria's hot and humid climate. Once mixed with water for injection, use it immediately or within a few 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.