PENTIDS '400'
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PENTIDS '400' (PENTIDS '400').
Penicillin G binds to penicillin-binding proteins (PBPs) located on the bacterial cell wall, inhibiting transpeptidase activity and disrupting peptidoglycan cross-linking, leading to cell lysis.
| Metabolism | Primarily excreted unchanged by the kidneys via tubular secretion. Minor hepatic metabolism (about 20%) to inactive penicilloic acid. Half-life: 30-60 minutes (normal renal function). |
| Excretion | Primarily renal (tubular secretion and glomerular filtration); 60-90% of dose excreted unchanged in urine within 24 hours. Minor biliary excretion (<10%) and fecal elimination. |
| Half-life | 0.5-1 hour in patients with normal renal function. Prolonged to 2-5 hours in renal impairment, requiring dose adjustment. |
| Protein binding | 65-75% bound to plasma proteins, primarily albumin. Binding is saturable at high concentrations. |
| Volume of Distribution | 0.3-0.4 L/kg (approximately 20-25 L in adults). Indicates distribution into extracellular fluid and well-perfused tissues; limited CNS penetration unless meninges inflamed. |
| Bioavailability | Oral: 60-80% (decreased by food, especially acidic foods). Intramuscular: ≈100% (complete bioavailability). Intravenous: 100%. |
| Onset of Action | Oral: 30-60 minutes (peak serum levels at 1-2 hours). Intramuscular: 15-30 minutes (peak at 30-60 minutes). Intravenous: immediate (peak at completion of infusion). |
| Duration of Action | 4-6 hours (dosing interval usually 6 hours). Reduced duration in severe infections or immunocompromised patients. Extended dosing intervals possible with probenecid co-administration. |
| Action Class | Cell wall active agent - Narrow spectrum Penicillin |
| Brand Substitutes | Pentas 400 Tablet, Pencip 400000IU Tablet |
400 mg orally every 6 hours.
| Dosage form | TABLET |
| Renal impairment | For GFR 10-50 mL/min: 400 mg every 8 hours. GFR <10 mL/min: 400 mg every 12 hours. |
| Liver impairment | Child-Pugh class A: no adjustment. Class B or C: 400 mg every 8 hours. |
| Pediatric use | For children >1 month: 6.25-12.5 mg/kg orally every 6 hours; maximum 400 mg/day. |
| Geriatric use | Start at lower end of dosing range (400 mg every 6-8 hours) due to potential renal impairment; monitor renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PENTIDS '400' (PENTIDS '400').
| Breastfeeding | Penicillin V is excreted into breast milk in low concentrations (M/P ratio approximately 0.2). It is generally considered compatible with breastfeeding. Potential for alteration of infant gut flora and hypersensitivity reactions, but adverse effects are rare. Use with caution in neonates with jaundice or prematurity. |
| Teratogenic Risk | FDA Pregnancy Category B: Animal studies have not demonstrated fetal risk, but no adequate human studies in pregnant women. Penicillin V (PENTIDS '400') crosses the placenta. No known teratogenic effects in first trimester; second and third trimester use is considered safe with no documented fetal harm. |
■ FDA Black Box Warning
WARNING: Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported in patients on penicillin therapy. These reactions are more likely to occur in individuals with a history of penicillin hypersensitivity and/or sensitivity to multiple allergens. There have been reports of individuals with a history of penicillin hypersensitivity who have experienced severe reactions when treated with cephalosporins. Before initiating therapy with penicillin, careful inquiry should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins, or other allergens. If an allergic reaction occurs, penicillin should be discontinued and appropriate therapy instituted. SERIOUS ANAPHYLACTIC REACTIONS REQUIRE IMMEDIATE EMERGENCY TREATMENT WITH EPINEPHRINE. OXYGEN, INTRAVENOUS STEROIDS, AND AIRWAY MANAGEMENT, INCLUDING INTUBATION, SHOULD ALSO BE ADMINISTERED AS INDICATED.
| Serious Effects |
["Hypersensitivity to penicillins or cephalosporins (absolute)","History of immediate-type hypersensitivity reaction (e.g., anaphylaxis, angioedema) to any beta-lactam antibiotic (absolute)","Patients with infectious mononucleosis (markedly increased risk of maculopapular rash) (relative; avoid use if alternative available)"]
| Precautions | ["Hypersensitivity reactions: Rash, fever, eosinophilia, angioedema, anaphylaxis. Cross-sensitivity with cephalosporins occurs in 5-10% of patients.","Neurotoxicity (high doses, renal impairment): seizures, confusion, myoclonus, coma.","Electrolyte disturbances: High doses of sodium salt may cause hypernatremia; potassium salt may cause hyperkalemia in renal failure.","Clostridium difficile-associated diarrhea (CDAD): Consider in patients presenting with diarrhea during or after therapy.","Jarisch-Herxheimer reaction: Fever, chills, myalgia, headache, exacerbation of skin lesions in syphilis treatment (due to endotoxin release).","Superinfection: Prolonged use may lead to overgrowth of nonsusceptible organisms (e.g., Candida).","Renal impairment: Dose adjustment required (creatinine clearance <10 mL/min: administer full loading dose then 50% of dose every 8-12 hours).","Hepatic impairment: No specific dosing recommendations but monitor liver function tests (rare hepatotoxicity)."] |
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| Fetal Monitoring | Monitor maternal renal function, signs of hypersensitivity or anaphylaxis. For prolonged therapy, monitor for superinfection. Fetal monitoring is not routinely required, but observe for any adverse reactions in the neonate if administered near term. |
| Fertility Effects | No known adverse effects on fertility. Penicillin V does not impair spermatogenesis or ovulation. No evidence of reduced reproductive capacity in animal studies. |