Vancomycin vs Daptomycin

Two peptide antibiotics for MRSA — one works in the lung, one never can.

The distinction that mattersBoth treat MRSA, and both are peptides. Vancomycin works in the lung; daptomycin is inactivated by surfactant and must never be used for pneumonia.

	Vancomycin FDA Approved	Daptomycin FDA Approved
Evidence rating	5/5 Very strong Evidence rating 5 out of 5: Very strong	5/5 Very strong Evidence rating 5 out of 5: Very strong
Regulatory status	FDA-approved for serious Gram-positive infections including MRSA, and orally for Clostridioides difficile infection.	FDA-approved for complicated skin and skin structure infections and for Staphylococcus aureus bacteraemia, including right-sided endocarditis.
Category	Antimicrobial & Antibiotic	Antimicrobial & Antibiotic
Drug class	Glycopeptide antibiotic — a heavily modified, glycosylated seven-residue peptide	Cyclic lipopeptide antibiotic — 13 amino acids with a decanoyl fatty acid tail
Route	Intravenous; oral for C. difficile colitis (not absorbed)	Intravenous, once daily
Half-life	~4–6 hours with normal renal function	~8–9 hours
Studied in	Seven decades of clinical use, numerous randomized trials, and randomized comparisons against fidaxomicin and metronidazole for C. difficile.	Randomized non-inferiority trials in complicated skin infection and in S. aureus bacteraemia and endocarditis; a pneumonia trial that failed and defined a contraindication.
Who should avoid it	Known vancomycin hypersensitivity or prior DRESS Caution in pre-existing renal impairment Avoid combining with piperacillin-tazobactam where an alternative exists	Pneumonia — inactivated by surfactant Known daptomycin hypersensitivity Caution with concurrent statin therapy
Legal status	Prescription antibiotic.	Prescription antibiotic administered in hospital or outpatient parenteral settings.

Benefits — Vancomycin

Reliable anti-MRSA activity
Long-standing first-line therapy for serious methicillin-resistant staphylococcal infection.
Oral therapy for C. difficile
Because it is not absorbed, oral vancomycin reaches very high colonic concentrations. Superior to metronidazole in randomized comparison and a guideline-recommended first-line agent.
Broad Gram-positive coverage
Active against streptococci, enterococci and Gram-positive anaerobes.
Inexpensive and universally available
Off-patent and stocked essentially everywhere.

Benefits — Daptomycin

Effective against MRSA bacteraemia
Non-inferior to standard therapy in a randomized trial, and a mainstay option when vancomycin fails or cannot be used.
Rapid bactericidal activity
Concentration-dependent killing, generally faster than vancomycin in vitro.
Once-daily dosing
Practical for outpatient parenteral antibiotic therapy.
Non-lytic killing
Avoids the inflammatory burst associated with cell-wall-lysing agents.

Risks & cons — Vancomycin

Nephrotoxicity
Dose- and exposure-related acute kidney injury, markedly increased when combined with piperacillin-tazobactam — one of the most clinically important interactions in hospital medicine.
Requires therapeutic drug monitoring
The therapeutic window is narrow; AUC-guided dosing is now recommended over trough-only monitoring.
Vancomycin infusion reaction
Histamine-mediated flushing of the upper body from rapid infusion. It is a rate-related reaction, not an allergy, and is prevented by slowing the infusion.
Ototoxicity
Uncommon but potentially permanent, particularly with aminoglycoside co-administration.
Rising MICs and treatment failure
Creeping minimum inhibitory concentrations in S. aureus are associated with worse outcomes even within the susceptible range.

Risks & cons — Daptomycin

Inactivated by pulmonary surfactant — useless in pneumonia
Its pneumonia trial failed because surfactant neutralises the drug in the alveolus. It must never be used for pneumonia, and this is a mechanism-level absolute.
Rhabdomyolysis and myopathy
Creatine kinase must be monitored at least weekly; the drug is stopped if CK rises with muscle symptoms.
Eosinophilic pneumonia
A distinct, serious hypersensitivity reaction that paradoxically affects the lungs, typically after 2 or more weeks of therapy.
Peripheral neuropathy
Reported with prolonged therapy.
Statin interaction
Concurrent statins compound muscle toxicity risk; many clinicians hold the statin during therapy.

A comparison is not a recommendation. Neither column is being suggested for you. Which — if either — is appropriate depends on your diagnosis, history and medications, and that is a conversation for a qualified clinician.