DAPTOMYCIN
Clinical safety rating: safe
Animal studies have demonstrated safety
Calcium-dependent binding to bacterial membranes, causing depolarization and inhibition of protein, DNA, and RNA synthesis.
| Metabolism | Minimally metabolized; renally excreted primarily as unchanged drug. |
| Excretion | Renal excretion of unchanged drug: approximately 78% (range 76-80%). Minimal biliary/fecal elimination (<5%). |
| Half-life | Terminal half-life: approximately 8-9 hours in patients with normal renal function. Prolonged in renal impairment; requires dose adjustment for CrCl <30 mL/min. |
| Protein binding | 90-95% bound, primarily to albumin. Binding is reversible and concentration-dependent. |
| Volume of Distribution | Steady-state Vd: approximately 0.1 L/kg. Low Vd indicates limited extravascular distribution; primarily distributes into extracellular fluid. |
| Bioavailability | Not available orally; intravenous administration only (100% bioavailability via IV route). |
| Onset of Action | Intravenous: Bactericidal activity begins within 1-2 hours post-infusion, with time-dependent killing. |
| Duration of Action | Duration: 12-24 hours. Once-daily dosing achieves sustained bactericidal concentrations. Post-antibiotic effect: approximately 2-6 hours against susceptible gram-positive organisms. |
| Molecular Weight | 1620.67 |
4-6 mg/kg intravenously once daily.
| Dosage form | POWDER |
| Renal impairment | CrCl >= 30 mL/min: no adjustment; CrCl < 30 mL/min: 4-6 mg/kg every 48 hours. |
| Liver impairment | No dose adjustment required for Child-Pugh class A, B, or C. |
| Pediatric use | 1-6 years: 10 mg/kg IV once daily; 7-11 years: 9 mg/kg IV once daily; 12-17 years: 7 mg/kg IV once daily. |
| Geriatric use | No specific dose adjustment; monitor renal function and use same dosing as adults. |
| 1st trimester | Limited human data; animal studies show no evidence of fetal harm at doses up to 75 mg/kg/day. Use only if clearly needed. |
| 2nd trimester | Limited human data; crosses placenta in animal models. Use cautiously if benefit outweighs risk. |
| 3rd trimester | Limited human data; no specific third-trimester risks identified. Monitor for maternal adverse effects. |
Clinical note
HMG-CoA reductase inhibitors may increase risk of myopathy May cause myopathy and rhabdomyolysis monitor CPK levels.
| Placental transfer | Crosses placenta in animal studies (rats: 0.3-2% of maternal plasma concentration); limited human data suggest minimal transfer. |
| Breastfeeding | Daptomycin is excreted in human milk in small amounts; relative infant dose estimated <1%. Consider risk of infant gut flora alteration; monitor for diarrhea or rash. |
■ FDA Black Box Warning
None.
| Common Effects | Myopathy |
| Serious Effects |
Hypersensitivity to daptomycin
| Precautions | Myopathy and rhabdomyolysis (monitor CPK levels), Eosinophilic pneumonia, Peripheral neuropathy, Clostridioides difficile-associated diarrhea, Decreased efficacy in patients with moderate to severe renal impairment |
| Food/Dietary | No significant food interactions reported. |
Loading safety data…
| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | FDA Pregnancy Category B. Animal studies show no fetal harm, but no adequate human studies. Use only if clearly needed. |
| Fetal Monitoring | Monitor for maternal adverse effects: CPK levels weekly, renal function, signs of myopathy. No specific fetal monitoring required. |
| Fertility Effects | No known effects on fertility in animal studies. |
| Clinical Pearls |
| Monitor CPK weekly due to risk of myopathy; avoid statins during therapy. Daptomycin is inactivated by pulmonary surfactant, so it is ineffective for pneumonia. Dose adjustment required for CrCl <30 mL/min (including hemodialysis). Has rapid bactericidal activity against Gram-positive organisms, including VRE and MRSA. May cause eosinophilic pneumonia and peripheral neuropathy with prolonged use. |
| Patient Advice | Report any muscle pain, weakness, or tenderness immediately. · Inform your doctor if you develop new cough, fever, or difficulty breathing. · Complete the full course of therapy even if you feel better. · Do not take statin medications (cholesterol-lowering drugs) without consulting your doctor. · This medication is given intravenously; infusion reactions may occur. |