PENTIDS '250'
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PENTIDS '250' (PENTIDS '250').
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.
| 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 |
| Molecular Weight | 350.39 |
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. |
| 1st trimester | Penicillin V is generally considered safe in the first trimester. Limited data show no increased risk of major birth defects. Use if clearly needed. |
| 2nd trimester | Safe for use; no known risks to the fetus. |
| 3rd trimester | Safe for use; no known risks to the fetus. |
Clinical note
Comprehensive clinical and safety monograph for PENTIDS '250' (PENTIDS '250').
| Placental transfer | Penicillin V crosses the placenta and achieves fetal serum concentrations approximately 20-30% of maternal levels. |
| Breastfeeding | Penicillin V is excreted into breast milk in small, non-toxic amounts. It is unlikely to cause adverse effects in a nursing infant. Use with caution in infants with renal impairment or colitis. |
| Lactation Rating |
■ 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.
| Serious Effects |
Hypersensitivity to penicillins or beta-lactam antibioticsHistory of immediate hypersensitivity reaction (e.g., anaphylaxis) to penicillins
| 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. |
| Food/Dietary | No significant food interactions. May be taken with food to reduce gastrointestinal upset. |
Loading safety data…
| L1 (Safe) |
| 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. |
| Fetal Monitoring | No specific maternal or fetal monitoring required beyond routine prenatal care. Observe for allergic reactions in mother and monitor for signs of infection. |
| Fertility Effects | No known adverse effects on fertility. Penicillin G does not impair reproductive function in animal studies. |
| Clinical Pearls | PENTIDS '250' is a penicillin G potassium formulation; always confirm patient allergy history before administration. Use with caution in renal impairment due to risk of neurotoxicity. Administer intramuscularly only; intravenous administration is contraindicated due to potential for severe phlebitis. Monitor for Jarisch-Herxheimer reaction in syphilis treatment. |
| Patient Advice | Complete full course of therapy even if symptoms improve. · Report any signs of allergic reaction (rash, itching, swelling, difficulty breathing) immediately. · Do not use if you are allergic to penicillin or cephalosporins. · Keep out of reach of children. · Store in refrigerator between 2-8°C; do not freeze. |