Daptomycin

Class: Lipopeptide antibiotic

Mechanism of Action: Binds to bacterial cell membranes of Gram-positive bacteria in a calcium-dependent manner, causing rapid depolarization, inhibition of protein, DNA, and RNA synthesis, leading to cell death.

Indications

• Complicated skin and skin structure infections caused by Gram-positive bacteria
• Bacteremia caused by Staphylococcus aureus, including MRSA
• Right-sided infective endocarditis due to Staphylococcus aureus
• Bone and joint infections (off-label, sometimes used)

Dosage

• Adults: 4 mg/kg IV once daily for skin infections; 6 mg/kg IV once daily for bacteremia and endocarditis
• Children: Safety and efficacy not fully established; dosing should be individualized

Maximum Dose

Not specifically defined; usually based on weight (mg/kg/day)

Major Side Effects

• Myopathy (muscle pain or weakness)
• Elevated creatine phosphokinase (CPK)
• GI disturbances: nausea, diarrhea, constipation
• Headache
• Insomnia

Contraindications

• Hypersensitivity to daptomycin
• Concurrent statin therapy (increased risk of myopathy; monitor CPK closely)

Compatible Fluids

• 0.9% Sodium Chloride
• 5% Dextrose

Route of Administration

• Intravenous (IV) infusion only

Type of Administration

• IV: Infuse over 30 minutes; do not administer via pulmonary route

Special Precautions

• Monitor CPK levels weekly; more frequently if patient is on statins or has renal impairment
• Adjust dose in severe renal impairment (CrCl <30 mL/min)
• Discontinue if myopathy develops
• Do not use for pneumonia (inactivated by pulmonary surfactant)
• Use cautiously in elderly and critically ill patients