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). |
| Molecular Weight | 349.4 |
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 | Ampicillin crosses the placenta. No well-controlled studies in first trimester. Use only if clearly needed. Animal studies show no teratogenicity. |
| 2nd trimester | Use with caution. Considered safe with maternal benefit > risk. |
| 3rd trimester | Use with caution. Avoid near term due to risk of hypersensitivity reactions. |
Clinical note
Comprehensive clinical and safety monograph for PENBRITIN-S (PENBRITIN-S).
| Placental transfer | Ampicillin crosses the placenta; peak cord serum concentrations approximate 50% of maternal serum levels. |
| Breastfeeding | Ampicillin is excreted into breast milk in low concentrations. Use with caution in breastfeeding. Monitor infant for diarrhea, rash, or sensitization. |
| Lactation Rating |
■ FDA Black Box Warning
Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported in patients on penicillin therapy.
| Serious Effects |
Hypersensitivity to ampicillin or any penicillinAllergy to cephalosporins (possible cross-sensitivity)Previous ampicillin-associated hepatitis or cholestatic jaundiceInfectious mononucleosis (ampicillin use associated with 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. |
| Food/Dietary | No significant food interactions; however, taking with food may reduce gastrointestinal upset. Avoid high-oxalate foods (e.g., spinach, rhubarb) as ampicillin may increase oxalate excretion. No restriction on alcohol but may increase risk of disulfiram-like reaction with sulbactam. |
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| L1 (Compatible) |
| 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. |
| 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. |
| Clinical Pearls | PENBRITIN-S is a combination of ampicillin and sulbactam; administer within 1 hour of reconstitution due to instability. Monitor for penicillin allergy cross-reactivity; use with caution in patients with mononucleosis due to high risk of maculopapular rash. Dose adjustment required in renal impairment (CrCl <30 mL/min). May cause false-positive urine glucose tests with Clinitest but not with glucose oxidase methods. |
| Patient Advice | Take exactly as prescribed; complete the full course even if you feel better. · Notify your doctor immediately if you develop rash, itching, severe diarrhea, or difficulty breathing. · This medication may cause diarrhea; contact your doctor if it becomes severe or contains blood or mucus. · Avoid alcohol while on this medication to reduce risk of side effects. · Inform your doctor if you are pregnant, breastfeeding, or have kidney disease. |