BRISTAMYCIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BRISTAMYCIN (BRISTAMYCIN).
BRISTAMYCIN is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidase activity, and activating autolytic enzymes.
| Metabolism | Primarily renal excretion; minor hepatic metabolism via hydrolysis to penicilloic acid. |
| Excretion | Renal: 80–90% unchanged via glomerular filtration and tubular secretion; biliary/fecal: <5% as unchanged drug and metabolites. |
| Half-life | Terminal elimination half-life: 6–8 hours (prolonged to 20–40 hours in severe renal impairment; dose adjustment required for CrCl <30 mL/min). |
| Protein binding | 80–85% primarily to albumin; minor binding to α1-acid glycoprotein. |
| Volume of Distribution | 0.3–0.5 L/kg, indicating limited extravascular distribution; higher in neonates and patients with edema. |
| Bioavailability | Oral: 60–80% (variable, reduced by food); IM: near 100%. |
| Onset of Action | IV: immediate; IM: 30–60 minutes; oral: 1–2 hours (dependent on gastric emptying). |
| Duration of Action | 12–24 hours depending on site and pathogen susceptibility; for UTIs, duration of bactericidal concentration in urine typically 24 hours after a single dose. |
500 mg intravenously every 6 hours. Infuse over 60 minutes.
| Dosage form | TABLET |
| Renal impairment | CrCl >60 mL/min: no adjustment; CrCl 30-60 mL/min: 500 mg every 8 hours; CrCl 15-29 mL/min: 500 mg every 12 hours; CrCl <15 mL/min: 500 mg every 24 hours; on hemodialysis: 500 mg every 24 hours, give after dialysis. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 250 mg every 6 hours; Child-Pugh C: 250 mg every 12 hours. |
| Pediatric use | Age <1 month: 30 mg/kg/day intravenously divided every 12 hours; Age 1 month to 12 years: 15-20 mg/kg intravenously every 6 hours; Max 1.5 g/day. |
| Geriatric use | No specific dosage adjustment beyond renal function; monitor renal function and adjust per CrCl as in renal_adjustment; consider increased risk of nephrotoxicity and neurotoxicity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BRISTAMYCIN (BRISTAMYCIN).
| Breastfeeding | BRISTAMYCIN is excreted into human breast milk with an M/P ratio of 1.5. Significant infant exposure may occur. Breastfeeding is contraindicated due to risks of neonatal toxicity, including hypotension, renal dysfunction, and potential neurodevelopmental effects. Use of expressed breast milk is not recommended during therapy and for 2 weeks after last dose. |
| Teratogenic Risk | BRISTAMYCIN is contraindicated in all trimesters due to dose-dependent teratogenicity. First trimester: high risk of major congenital malformations, including neural tube defects, cleft palate, and cardiac anomalies. Second trimester: increased risk of fetal growth restriction and neurodevelopmental toxicity. Third trimester: risk of preterm birth, low birth weight, and neonatal toxicity (hypotension, renal impairment, pulmonary hypertension). |
■ FDA Black Box Warning
Patients with a history of immediate hypersensitivity reactions to penicillins or cephalosporins may experience severe anaphylaxis. Resuscitative equipment should be available during administration.
| Serious Effects |
Hypersensitivity to penicillins or cephalosporins; history of immediate-type hypersensitivity reactions to beta-lactam antibiotics.
| Precautions | Monitor renal function in patients with renal impairment; risk of superinfection with prolonged use; use caution in patients with history of allergies. |
| Food/Dietary | No specific food interactions. Alcohol should be avoided due to risk of disulfiram-like reaction (headache, nausea, flushing). |
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| Fetal Monitoring | Maternal: Baseline and serial renal function (serum creatinine, BUN, urinalysis), hepatic panel (ALT, AST, bilirubin), complete blood count with differential, and blood pressure monitoring. Fetal: Serial ultrasound for growth, amniotic fluid index, and anatomy; fetal echocardiogram at 20-24 weeks gestation; third-trimester biophysical profile. Monitor for signs of preeclampsia and fetal distress. |
| Fertility Effects | Animal studies and limited human data suggest reversible impairment of spermatogenesis in males (oligospermia, decreased motility) and menstrual irregularities in females, possibly due to hormonal disruption. Fertility may be reduced during therapy; effects typically resolve 3-6 months after discontinuation. Long-term reproductive outcomes are not well studied. |
| Clinical Pearls |
| BRISTAMYCIN is a cephalosporin antibiotic with activity against Gram-positive and some Gram-negative bacteria. Administer IV over 30 minutes to reduce infusion-related phlebitis. Monitor renal function in elderly or nephrotoxic co-administration. Cross-allergenicity with penicillins occurs in ~5% of patients. |
| Patient Advice | Complete the full course of therapy even if you feel better. · Report any signs of allergic reaction (rash, itching, difficulty breathing) immediately. · Avoid alcohol during treatment and for 48 hours after to prevent disulfiram-like reactions. · Inform your doctor if you have kidney disease or are taking anticoagulants. |