ZINPLAVA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZINPLAVA (ZINPLAVA).
Bezlotoxumab is a human monoclonal antibody that binds to Clostridioides difficile toxin B, neutralizing its activity and preventing damage to colonic epithelial cells.
| Metabolism | Bezlotoxumab is a monoclonal antibody; it is degraded via general protein catabolism into small peptides and amino acids. No specific metabolic enzymes are involved. |
| Excretion | Primarily eliminated via fecal excretion as unchanged drug (approximately 79% of dose), with minimal renal excretion (about 15% as unchanged drug). |
| Half-life | Mean terminal elimination half-life is approximately 19 days (range 14–22 days), supporting a 6-week dosing interval. |
| Protein binding | Approximately 79–86% bound, primarily to human serum albumin. |
| Volume of Distribution | Volume of distribution at steady state is approximately 0.21 L/kg, indicating limited extravascular distribution and primarily intravascular space. |
| Bioavailability | Intravenous administration only; bioavailability is 100% by the IV route. Not administered orally or by other routes. |
| Onset of Action | Onset of clinical effect (reduction in Clostridioides difficile infection recurrence) is observed within 2–3 days after a single IV infusion, correlating with attainment of therapeutic serum concentrations. |
| Duration of Action | Duration of action is approximately 12 weeks after a single 10 mg/kg IV infusion, providing protection against recurrence throughout the high-risk period. |
10 mg/kg intravenously over 60 minutes, single dose.
| Dosage form | INJECTABLE |
| Renal impairment | No adjustment necessary for any degree of renal impairment, including end-stage renal disease. |
| Liver impairment | No adjustment necessary for mild, moderate, or severe hepatic impairment (Child-Pugh A, B, or C). |
| Pediatric use | Safety and efficacy not established in pediatric patients. |
| Geriatric use | No specific dose adjustment required; clinical studies included patients ≥65 years with no overall differences in safety or efficacy. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ZINPLAVA (ZINPLAVA).
| Breastfeeding | No data on presence in human milk, effects on breastfed infant, or milk production. Monoclonal antibodies generally have low transfer to breast milk. M/P ratio not known. |
| Teratogenic Risk | No adequate and well-controlled studies in pregnant women. Animal reproduction studies have not been conducted. Based on mechanism of action (monoclonal antibody), negligible placental transfer expected; however, IgG antibodies cross placenta, especially in third trimester. Risk cannot be ruled out. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["None known."]
| Precautions | ["Heart failure: Use with caution in patients with a history of congestive heart failure; adverse reactions including death have been reported in clinical trials.","Infusion-related reactions: Monitor for signs of hypersensitivity, including anaphylaxis and serum sickness."] |
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| No specific monitoring required. As with any biologic, observe for hypersensitivity reactions. Monitor for signs of infection. |
| Fertility Effects | No data on fertility impairment. Animal studies not conducted. Based on mechanism, effects on fertility are unlikely. |