PENBRITIN-S
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PENBRITIN-S (PENBRITIN-S).
Penicillinase-sensitive penicillin; inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidase activity, and activating autolytic enzymes.
| Metabolism | Primarily renal excretion; undergoes hepatic metabolism to a minor extent (penicilloic acid). |
| Excretion | Renal: 75-90% unchanged via glomerular filtration and tubular secretion; biliary/fecal: ~10%. |
| Half-life | 0.5-1 hour; prolonged in renal impairment (up to 7-10 hours in anuria). |
| Protein binding | 20-30% bound to serum albumin. |
| Volume of Distribution | 0.3-0.4 L/kg, approximates extracellular fluid volume. |
| Bioavailability | Oral: 30-60% (dose and food dependent); IM: ~85%. |
| Onset of Action | Oral: 30-60 min; IM: 15-30 min; IV: immediate. |
| Duration of Action | Oral: 4-6 hours; IM/IV: 4-6 hours (dose-dependent). |
250-500 mg orally every 6 hours or 500 mg-1 g intramuscularly/intravenously every 4-6 hours for moderate to severe infections.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl >50 mL/min: no adjustment; CrCl 10-50 mL/min: administer every 6-12 hours; CrCl <10 mL/min: administer every 12-24 hours. |
| Liver impairment | No specific Child-Pugh based adjustments; use normal dosing unless severe hepatic impairment with concomitant renal dysfunction; monitor for toxicity. |
| Pediatric use | Children >20 kg: 250-500 mg orally every 6 hours; <20 kg: 50-100 mg/kg/day divided every 6 hours; maximum 2-4 g/day orally or 100-200 mg/kg/day IV/IM divided every 4-6 hours. |
| Geriatric use | No specific adjustment based on age alone; evaluate renal function and adjust accordingly per renal guidelines; may require lower initial doses due to decreased renal clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PENBRITIN-S (PENBRITIN-S).
| Breastfeeding | Ampicillin and sulbactam are excreted into breast milk in low concentrations (M/P ratio for ampicillin ~0.02-0.04; sulbactam unknown). Generally considered compatible with breastfeeding. Monitor infant for diarrhea or rash. |
| Teratogenic Risk | PENBRITIN-S (ampicillin/sulbactam) is generally considered low risk in pregnancy. Animal studies have not shown teratogenicity, and no adequate well-controlled human studies exist. First trimester: No evidence of increased major malformations; second and third trimesters: Safe for use, risk of neonatal kernicterus theoretical but not reported. |
■ FDA Black Box Warning
Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported in patients on penicillin therapy.
| Serious Effects |
Known hypersensitivity to penicillins or beta-lactam antibiotics; use cautiously in patients with mononucleosis due to high incidence of rash.
| Precautions | Monitor for hypersensitivity reactions; use with caution in patients with renal impairment, history of allergies, or cystic fibrosis (increased rash risk). Prolonged use may lead to superinfection. |
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| Fetal Monitoring | Monitor maternal renal function (ampicillin/sulbactam cleared renally); assess for signs of maternal allergic reactions; fetal monitoring not routinely required unless maternal adverse effects occur. |
| Fertility Effects | No adverse effects on fertility reported in animal studies. No known human fertility impact. |