Clinical medicine profile
Benzathine Penicillin
Beta-lactam antibiotic — penicillin
- Route
- ORAL / PARENTERAL (agent-dependent)
- Schedule
- POM
- ATC
- Not assigned
- PPB status
- registered
This profile needs source confirmation
A traceable source link is not attached to this profile. Confirm prescribing decisions against the current SmPC and Kenya STG/EML.
Safety essentials
The information most likely to change a prescribing or dispensing decision.
Contraindications
- History of serious immediate hypersensitivity (e.g. anaphylaxis, angioedema, urticaria) to any penicillin.
- Caution with prior severe cephalosporin reaction (cross-reactivity risk).
- Avoid in infectious mononucleosis if using aminopenicillins (rash risk).
Precautions
- For deep IM administration only
- do not administer IV, SC, or IT.
- Inadvertent IV administration associated with cardiorespiratory arrest and death.
- Do not inject near nerve or artery.
Dosing matrix
Population and organ-function guidance, shown together for faster comparison.
Streptococcal [Group A] upper respiratory infections [e.g, pharyngitis]: Adults: a single injec- tion of 1,200,000 units; older children: a single injection of 900,000 units; infants and children: 300,000 to 600,000 units. Syphilis [less than 1 yr]: 2.4 m.u weekly for 2 weeks. Syphilis [more than 1 yr]: 4 m.u weekly for 4-5 weeks. Yaws, bejel, and pinta: 1,200,000 units [1 injection]. Prophylaxis for rheumatic fever and glomerulonephritis following an acute attack: Penicillin G Benzathine [parenteral] may be given in doses of 1,200,000 units once a month or 600,000 units every 2 weeks.
See label paediatric section if present; otherwise use paediatric formulary — do not extrapolate adult doses.
Renal excretion dominant — reduce dose or extend interval in significant renal impairment; risk of accumulation and seizures at high levels.
- CrCl 0–120: Confirm renal dosing in product SmPC / primary label.
Low intrinsic hepatotoxicity; cholestatic hepatitis rare (notably flucloxacillin/co-amoxiclav patterns for related agents).
Use, effects & interactions
Indications
- Therapeutic use is agent- and indication-specific within the class (Beta-lactam antibiotic — penicillin).
- Use according to culture results, national guidelines (Kenya STG/EML where applicable) and the current product SmPC.
- See under the dosage
Adverse effects
- Common: gastrointestinal upset, diarrhoea, mild rash.
- Serious: anaphylaxis, Stevens–Johnson syndrome / TEN (rare), antibiotic-associated colitis (including C. difficile), interstitial nephritis, haematological reactions with prolonged high dose.
Drug interactions
Open multi-drug checker ↗- For professionals: select agent by suspected pathogen and local resistance.
- Natural penicillins remain first-line for many streptococcal infections when susceptibility expected.
- Do not use penicillin alone for beta-lactamase-producing staphylococci.
- Document allergy phenotype (immediate vs delayed).
- De-escalate once cultures allow.
Mechanism & disposition
terferes with the synthesis of peptidoglycans, which are part of bacterial cell wall [bactericidal].
Read complete mechanism
terferes with the synthesis of peptidoglycans, which are part of bacterial cell wall [bactericidal]. It is the most appropriate drug when prolonged low levels of benzylpenicillin are needed. It has a prolonged antibiotic action (2 - 4 wks after a STAT IM dose).
Within 1 hour (oral); faster IV
4–8 hours typical (agent/formulation dependent)
ORAL / PARENTERAL (agent-dependent)
is predominantly renal (glomerular filtration and tubular secretion). Dose adjustment is often required in severe renal impairment. Probenecid reduces tubular secretion and prolongs levels.
differ by agent and salt/ester. Most penicillins distribute widely into extracellular fluid; CSF penetration is poor unless meninges are inflamed.
Pregnancy, lactation & diet
Penicillins are generally considered compatible in pregnancy when clearly indicated (decades of clinical use). Prefer agents with the best safety record for the indication; confirm current SmPC.
Usually compatible with breastfeeding; small amounts excreted in milk. Monitor infant for diarrhoea, thrush or rash.
Brands & loaded prices
| Brand | Manufacturer | Pack | Observed price |
|---|---|---|---|
| CAREBENZAR | Not recorded | 2.4MEGA VIAL 10*S | KES 321.43Daima Chemist price-list reference ↗ Source date not recorded · verify current price |
Sources & review state
Decision support only. Confirm patient-specific decisions against the current product SmPC, Kenya STG/EML, and professional judgement.