PENTIDS '250'

Clinical safety rating: caution

Comprehensive clinical and safety monograph for PENTIDS '250' (PENTIDS '250').

How it works

Penicillin G binds to penicillin-binding proteins (PBPs) located on the bacterial cell wall, inhibiting transpeptidase activity and cell wall synthesis, leading to bacterial lysis.

What the body does with it

Metabolism	Primarily renal tubular secretion (90% unchanged). Minor hepatic metabolism to penicilloic acid (inactive).
Excretion	Primarily renal (60-90% as unchanged drug via glomerular filtration and tubular secretion); minor biliary/fecal (10-30%)
Half-life	0.5-1 hour (prolonged in renal impairment; requires dose adjustment when CrCl <30 mL/min)
Protein binding	Approximately 20% bound, primarily to serum albumin
Volume of Distribution	0.3-0.4 L/kg (limited tissue penetration; primarily extracellular fluid)
Bioavailability	Oral: 25-40% (decreased by food; acid-labile); Intramuscular: 70-85%
Onset of Action	Oral: 30-60 minutes; Intramuscular: 15-30 minutes; Intravenous: immediate
Duration of Action	4-6 hours for susceptible organisms; longer for high-dose regimens; clinically significant for dosing every 6 hours

Classification & Brands

Dosing & administration

250 mg orally every 8 hours.

Dosage form	TABLET
Renal impairment	For GFR 10-50 mL/min: 250 mg every 12 hours; GFR <10 mL/min: 250 mg every 24 hours.
Liver impairment	No adjustment required for mild to moderate impairment; severe impairment (Child-Pugh C): consider dose reduction to 250 mg every 12 hours due to risk of accumulation.
Pediatric use	For children >12 years: 250 mg orally every 8 hours; for children 2-12 years: 6.25-12.5 mg/kg orally every 8 hours (max 250 mg per dose); for infants and neonates: 25-50 mg/kg/day divided every 6-8 hours based on gestational and postnatal age.
Geriatric use	Elderly patients may require dose adjustment based on renal function; start at 250 mg every 12 hours and titrate to response, monitoring for adverse effects.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for PENTIDS '250' (PENTIDS '250').

Breastfeeding	Penicillin G is excreted into breast milk in low concentrations (M/P ratio approximately 0.1-0.2). It is considered compatible with breastfeeding due to minimal infant exposure; risk of diarrhea or allergic sensitization is low but possible.
Teratogenic Risk	Penicillin G (PENTIDS '250') is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, and there are no adequate well-controlled studies in pregnant women. First trimester: No evidence of teratogenicity in humans. Second and third trimesters: Considered safe; no documented fetal harm.

Warnings & precautions

■ FDA Black Box Warning

WARNING: ACCIDENTAL INJECTION INTO A NERVE OR BLOOD VESSEL MAY CAUSE NEUROVASCULAR DAMAGE. INTRA-ARTERIAL OR INTRAVENOUS ADMINISTRATION OF THE SUSPENSION IS CONTRAINDICATED.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to penicillins or any component of the formulation.","Hypersensitivity to procaine (for procaine-containing formulations).","Intra-arterial or intravenous administration of the aqueous suspension."]

Clinical Precautions

Precautions

["Hypersensitivity reactions (anaphylaxis) – prior to therapy, inquire about penicillin/cephalosporin allergies.","Serious and occasionally fatal hypersensitivity reactions (including anaphylaxis) more frequent with parenteral therapy.","Neurologic adverse events (e.g., convulsions) with high doses or renal impairment.","Clostridioides difficile-associated diarrhea (CDAD) may occur.","Prolonged use may result in bacterial or fungal superinfection.","Use caution in patients with renal impairment (adjust dose).","Penicillin G procaine may cause procaine-induced adverse reactions."]

Clinical Tips & Counseling

Drug interactions

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PENTIDS '250'

Clinical safety rating: caution

Comprehensive clinical and safety monograph for PENTIDS '250' (PENTIDS '250').

How it works

Penicillin G binds to penicillin-binding proteins (PBPs) located on the bacterial cell wall, inhibiting transpeptidase activity and cell wall synthesis, leading to bacterial lysis.

What the body does with it

Metabolism	Primarily renal tubular secretion (90% unchanged). Minor hepatic metabolism to penicilloic acid (inactive).
Excretion	Primarily renal (60-90% as unchanged drug via glomerular filtration and tubular secretion); minor biliary/fecal (10-30%)
Half-life	0.5-1 hour (prolonged in renal impairment; requires dose adjustment when CrCl <30 mL/min)
Protein binding	Approximately 20% bound, primarily to serum albumin
Volume of Distribution	0.3-0.4 L/kg (limited tissue penetration; primarily extracellular fluid)
Bioavailability	Oral: 25-40% (decreased by food; acid-labile); Intramuscular: 70-85%
Onset of Action	Oral: 30-60 minutes; Intramuscular: 15-30 minutes; Intravenous: immediate
Duration of Action	4-6 hours for susceptible organisms; longer for high-dose regimens; clinically significant for dosing every 6 hours

Classification & Brands

Dosing & administration

250 mg orally every 8 hours.

Dosage form	TABLET
Renal impairment	For GFR 10-50 mL/min: 250 mg every 12 hours; GFR <10 mL/min: 250 mg every 24 hours.
Liver impairment	No adjustment required for mild to moderate impairment; severe impairment (Child-Pugh C): consider dose reduction to 250 mg every 12 hours due to risk of accumulation.
Pediatric use	For children >12 years: 250 mg orally every 8 hours; for children 2-12 years: 6.25-12.5 mg/kg orally every 8 hours (max 250 mg per dose); for infants and neonates: 25-50 mg/kg/day divided every 6-8 hours based on gestational and postnatal age.
Geriatric use	Elderly patients may require dose adjustment based on renal function; start at 250 mg every 12 hours and titrate to response, monitoring for adverse effects.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for PENTIDS '250' (PENTIDS '250').

Breastfeeding	Penicillin G is excreted into breast milk in low concentrations (M/P ratio approximately 0.1-0.2). It is considered compatible with breastfeeding due to minimal infant exposure; risk of diarrhea or allergic sensitization is low but possible.
Teratogenic Risk	Penicillin G (PENTIDS '250') is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, and there are no adequate well-controlled studies in pregnant women. First trimester: No evidence of teratogenicity in humans. Second and third trimesters: Considered safe; no documented fetal harm.

Warnings & precautions

■ FDA Black Box Warning

WARNING: ACCIDENTAL INJECTION INTO A NERVE OR BLOOD VESSEL MAY CAUSE NEUROVASCULAR DAMAGE. INTRA-ARTERIAL OR INTRAVENOUS ADMINISTRATION OF THE SUSPENSION IS CONTRAINDICATED.