Benzathine benzylpenicillin

Generic Medicine Info
Indications and Dosage
Erysipelas, Primary prophylaxis of rheumatic fever, Streptococcal pharyngitis, Streptococcal tonsillitis
Adult: 1,200,000 units as a single dose.
Child: ≤27 kg 300,000-600,000 units as a single dose; >27 kg 900,000-1,200,000 units as a single dose.

Adult: Primary or secondary: 2,400,000 units as a single dose. Latent seropositive: 2,400,000 units once weekly for 3 weeks.
Child: Primary or secondary: 50,000 units/kg as a single dose. Max: 2,400,000 units. Latent seropositive: 50,000 units/kg once weekly for 3 weeks. Max: 2,400,000 units/dose.

Bejel, Pinta, Yaws
Adult: 1,200,000 units as a single dose.
Child: <30 kg 600,000 units as a single dose; >30 kg Same as adult dose.

Congenital syphilis
Child: In patients with normal CSF: <2 years 50,000 units/kg as a single dose; 2-12 years Adjust based on adult dosage schedule.

Prophylaxis of erysipelas, Prophylaxis of poststreptococcal glomerulonephritis, Prophylaxis of recurrent rheumatic fever
Adult: 1,200,000 units every 3-4 weeks or 600,000 units every 2 weeks. Duration of treatment depends on the severity of condition and cardiac involvement (refer to detailed product guidelines).
Child: ≤27 kg 600,000 units; >27 kg 1,200,000 units. All doses are given once every 3-4 weeks. Duration of treatment depends on the severity of condition and cardiac involvement (refer to detailed product guidelines).
Reconstitution of powder for inj may vary between products (refer to individual product guidelines).
Hypersensitivity to benzathine benzylpenicillin and other penicillins, cephalosporins, carbapenem, or monobactam.
Special Precautions
Patient with allergic diathesis and bronchial asthma; history of seizure disorders. Renal and hepatic impairment. Children and elderly. Pregnancy and lactation. Avoid IV or intra-arterial administration, or inj near major peripheral nerves or blood vessels.
Adverse Reactions
Significant: Severe cutaneous adverse reactions (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, and acute generalised exanthematous pustulosis); Jarisch-Herxheimer reaction (during syphilis treatment).
Blood and lymphatic system disorders: Haemolytic anaemia, leucopenia, thrombocytopenia.
Cardiac disorders: Tachycardia, palpitations.
Ear and labyrinth disorders: Tinnitus.
Eye disorders: Blurred vision, blindness.
Gastrointestinal disorders: Nausea, vomiting, glossitis, dysgeusia, diarrhoea, blood in stool, stomatitis, intestinal necrosis.
General disorders and administration site conditions: Fever, fatigue, asthenia, pain, injection site reactions (e.g. pain, arthropathy, inflammation, lump, oedema, abscess, bleeding, ulceration, necrosis).
Immune system disorders: Urticaria.
Infections and infestations: Candidiasis.
Investigations: Elevated BUN, creatinine, SGOT.
Musculoskeletal and connective tissue disorders: Arthralgia, joint disorder, periostitis, exacerbation of arthritis, rhabdomyolysis.
Nervous system disorders: Headache, dizziness, nervousness, tremors, somnolence.
Renal and urinary disorders: Nephropathy, interstitial nephritis.
Reproductive system and breast disorders: Impotence, priapism.
Respiratory, thoracic, and mediastinal disorders: Hypoxia, apnoea, dyspnoea.
Skin and subcutaneous tissue disorders: Diaphoresis.
Vascular disorders: Hypotension.
Potentially Fatal: Serious hypersensitivity (anaphylactic) reactions; superinfections e.g. Clostridioides difficile-associated diarrhoea, pseudomembranous colitis.
Patient Counseling Information
This drug may cause allergic reactions, dizziness, or seizures, if affected, do not drive, or operate machinery.
Monitoring Parameters
Perform culture and susceptibility tests prior to treatment initiation; consult local institutional recommendations before treatment initiation due to antibiotic resistance risks. Monitor for signs and symptoms of anaphylaxis during 1st dose.
Symptoms: Neuromuscular hyperirritability or convulsive seizures. Management: Symptomatic treatment and clinical monitoring.
Drug Interactions
Antagonised bactericidal effect with bacteriostatic antibiotics e.g. tetracycline. Increased serum penicillin levels with probenecid, anti-inflammatories, antirheumatics, antipyretics (e.g. indomethacin, phenylbutazone, high doses of salicylates). Increased risk of bleeding with anticoagulants. May decrease the excretion of methotrexate. May occasionally reduce the efficacy of oral contraceptives.
Lab Interference
May cause positive direct Coombs' test; false-positive urinary and/or serum proteins; false-positive or negative urinary glucose using Clinitest®.
Mechanism of Action: Benzathine benzylpenicillin is a β-lactam antibiotic. It interferes with bacterial cell wall biosynthesis, rendering the cell wall osmotically unstable hence causing cell wall rupture leading to bacterial cell death.
Synonym(s): Benzathine penicillin G.
Duration: 1-4 weeks.
Absorption: Very slowly absorbed from the IM site into the bloodstream. Time to peak plasma concentration: 12-24 hours.
Distribution: Distributed throughout the body tissues: kidneys, liver, skin, intestines (highest level), and CSF (minimal amount). Crosses the placenta and enters breast milk. Plasma protein binding: Approx 60%.
Metabolism: Hydrolysed to benzylpenicillin.
Excretion: Mainly via urine (70-80%).
Chemical Structure

Chemical Structure Image
Benzathine benzylpenicillin

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 25137901, Bicillin L-A. Accessed Nov. 28, 2023.

Pre-filled syringe: Store between 2-8°C. Do not freeze. Intact Vial: Store below 30°C.
MIMS Class
ATC Classification
J01CE08 - benzathine benzylpenicillin ; Belongs to the class of beta-lactamase sensitive penicillins. Used in the systemic treatment of infections.
Anon. Benzylpenicillin (Penicillin G) Benzathine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. Accessed 04/08/2023.

Anon. Penicillin G Benzathine. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. Accessed 04/08/2023.

Benzapen 2.4 MIU Injection Sterile (Averroes Pharmaceuticals Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. Accessed 04/08/2023.

Benzylpenicillin Benzathine 2.4 Million I.U. Powder for Suspension for Injection (Brancaster Pharma Limited). MHRA. Accessed 04/08/2023.

Bicillin L-A Injection, Suspension (A-S Medication Solutions). DailyMed. Source: U.S. National Library of Medicine. Accessed 04/08/2023.

Buckingham R (ed). Benzathine Benzylpenicillin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. Accessed 04/08/2023.

Joint Formulary Committee. Benzathine Benzylpenicillin. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. Accessed 04/08/2023.

Pfizer New Zealand Limited. Bicillin L-A 1,200,000 Units/2.3 mL Suspension for Injection data sheet 14 January 2022. Medsafe. Accessed 04/08/2023.

Disclaimer: This information is independently developed by MIMS based on Benzathine benzylpenicillin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2024 MIMS. All rights reserved. Powered by
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